Email Subject Line Generator
Compelling subject lines for fundraising/program emails
The Prompt
The Prompt
Generate 7 high-performing email subject lines for [ORGANIZATION NAME]’s [CAMPAIGN TYPE] campaign.
REQUIRED INPUTS
- Organization name: [ORGANIZATION NAME]
- Campaign type: [CAMPAIGN TYPE]
Examples: year-end appeal, Giving Tuesday, event invitation, volunteer recruitment, advocacy alert, monthly newsletter
- Primary goal/CTA: [GOAL/CTA]
Examples: donate $50, sign petition, register for gala, volunteer sign-up
- Tone: [TONE: WARM/FORMAL/CASUAL]
- WARM: friendly, mission-centered (most donors/volunteers)
- FORMAL: clear, respectful (funders/institutions)
- CASUAL: upbeat, conversational (peers/younger audiences)
OPTIONAL INPUTS (use any; defaults apply if blank)
- Audience segment: [AUDIENCE SEGMENT] (default: general supporters)
- Key benefit/impact: [BENEFIT/IMPACT] (example: “$50 provides 100 meals”)
- Deadline: [DEADLINE DATE] (if time-sensitive)
- Location: [CITY/REGION] (for local relevance)
- Email platform: [EMAIL PLATFORM] (Mailchimp, Constant Contact, Campaign Monitor, HubSpot)
- Emoji policy: [EMOJI POLICY: NONE/LIMITED/OK] (default: LIMITED)
- Personalization: [YES/NO] (default: YES)
- First name tag: [FIRST NAME TAG] (examples: Mailchimp {{FirstName}}, Constant Contact [First Name], Campaign Monitor [firstname], HubSpot {{contact.firstname}})
- City tag (optional): [CITY TAG] (examples: {{City}}, [City])
- Fallback term if name/city missing: [FALLBACK: friend/supporter/neighbor] (default: friend)
- From-name preference: [FROM NAME PREFERENCE: ORG/STAFF/CEO] (default: STAFF for appeals; ORG for updates)
OUTPUT FORMAT
SECTION 1: TOP 2 SUBJECT LINES (Ready to A/B test)
For each option provide:
- Subject line (40–60 characters ideal; up to 70 if needed). Include character count.
- Brief rationale (one sentence on benefit or curiosity hook)
- Complementary preheader (50–90 characters; adds context; does not repeat the subject). Include character count.
- Two versions: with emoji and without emoji (only if allowed by Emoji policy). Recommend specific emoji only if policy is LIMITED/OK.
SECTION 2: 5 ADDITIONAL OPTIONS
- Provide 5 more subject lines with character counts and one-sentence rationales.
- Label each with its type: curiosity-led, benefit-led, action-led, or personalized.
- Mix across all 7 total: 2 curiosity-led, 2 benefit-led, 2 action-led, 1 personalized (uses [FIRST NAME TAG] or [CITY TAG] with fallback).
SECTION 3: PREHEADERS FOR THE 5 ADDITIONAL OPTIONS
- Provide a matching preheader for each (50–90 characters; add context; no repetition of the subject). Include character counts.
SECTION 4: SPAM & DELIVERABILITY CHECK
- Flag any potential triggers (FREE, URGENT, ACT NOW, $$$, ALL CAPS, excessive punctuation like !!! or ???).
- If any appear, provide a clean rewrite immediately below.
- Note any risky phrasing and how you mitigated it.
SECTION 5: A/B TEST RECOMMENDATION
- Choose two subject lines to test.
- Select ONE variable: emoji vs none, benefit vs curiosity, personalized vs generic, or short vs long.
- Hypothesis: “We predict [VERSION A] will perform better because [REASON].”
- Success metric: open rate (nonprofit benchmark ~20–25%). Note any list-specific considerations.
SECTION 6: FROM NAME RECOMMENDATION
- Recommend 1–2 “From name” options aligned to [FROM NAME PREFERENCE] and campaign type.
Examples:
- Personal appeals/stories: “[STAFF/CEO NAME] at [ORG NAME]”
- Organizational updates: “[ORG NAME]”
- Peer-to-peer/grassroots: “[Staff First Name], [ORG NAME]”
- Include a brief note on why this format fits the audience and goal.
QUALITY STANDARDS
- Character length: 40–60 characters ideal for mobile; 60–70 acceptable for desktop-heavy audiences.
Mobile inboxes often truncate around 30–40 characters—front-load key words.
- Reading level: 6th–8th grade; short, clear sentences; nonprofit voice.
- Lead with benefit or thoughtful curiosity; avoid clever-but-unclear wording.
- Action-oriented verbs; highlight real impact (e.g., “your gift provides [IMPACT/UNIT]”).
- Avoid guilt trips, bait-and-switch, ALL CAPS, excessive punctuation, spammy language.
- Personalization: include merge tags only when they add value; always include a fallback term.
- Accessibility: do not rely on emoji alone; ensure meaning stands without emoji.
- Paste-ready for small teams using [EMAIL PLATFORM]; keep formatting simple.
- Test one variable at a time; document outcomes for learning.
NOTES ON CHARACTER COUNTS AND PREVIEWS
- 40–60 characters generally shows well on mobile and most inboxes.
- 60–70 characters can work for desktop-heavy audiences or when clarity needs a few extra words.
- Always put the most important words first to survive truncation.
EXAMPLE INPUT (for reference)
- Organization name: City Food Bank
- Campaign type: Year-end giving appeal
- Primary goal/CTA: Donate $50 to provide holiday meals
- Tone: WARM
- Audience segment: Lapsed donors (gave 12–24 months ago)
- Key benefit/impact: $50 provides 100 meals
- Deadline: December 31
- Email platform: Mailchimp
- Emoji policy: LIMITED
- Personalization: YES (First name tag {{FirstName}}, fallback: friend)
- From-name preference: STAFF
EXAMPLE OUTPUT (abbreviated)
SECTION 1: TOP 2
Option A
- Subject: {{FirstName}}, 100 meals start with you (39)
- Rationale: Personalization plus concrete impact builds ownership and clarity.
- Preheader: Your $50 puts holiday meals on neighbors’ tables before Dec 31. (78)
- With emoji: {{FirstName}}, 100 meals start with you 🍽️ (41)
- Without emoji: {{FirstName}}, 100 meals start with you (39)
Option B
- Subject: The holiday gift that feeds 100 neighbors (45)
- Rationale: Benefit-forward with community connection and seasonal relevance.
- Preheader: Make your year-end gift to City Food Bank by December 31. (73)
- With emoji: The holiday gift that feeds 100 neighbors ❤️ (47)
- Without emoji: The holiday gift that feeds 100 neighbors (45)
[Sections 2–6 would continue in the same format.]
NEXT STEPS AFTER GENERATION
1) Review the top 2 with your team and confirm tone/fit.
2) Load both into [EMAIL PLATFORM] as A/B variants; split audience 50/50 or use automatic winner.
3) If your list is large, send to 10–20% first; wait 2–4 hours.
4) Declare winner by open rate; send the winner to the remainder.
5) Log results (winning variant, variable tested, open rate) to inform future campaigns.
If unsure about any input, start with only the 4 required fields. Reasonable defaults will be applied for optional items based on nonprofit best practices.
How to Customize
- Replace all [BRACKETED] fields with your specific information
- Adjust tone and length as needed for your audience
- Review and personalize before using
Pro Tips
- Test this prompt with your preferred AI tool before using in production
- Always review AI output for accuracy and appropriateness
- Customize outputs to match your organization’s voice and brand
Related Prompts
(See other prompts in the communications category)
Example Outputs
Compare scenarios: We tested this prompt with 3 different nonprofit contexts. Each scenario shows outputs from GPT-5, Claude, and Gemini. Select a model above each scenario to compare.
Small Community Org
Rural animal rescue recruiting winter foster volunteers before cold weather; local audience, casual tone.
View scenario details
SECTION 1: TOP 2 SUBJECT LINES (Ready to A/B test)
Option A (Benefit-led) - Subject: One winter foster = 3 lives saved in Red Willow (47) - Rationale: Concrete impact plus local tie-in makes the value clear fast. - Preheader: Foster 6–8 weeks, make room for 3 emergency intakes by Nov 30, 2025. (68) - With emoji: One winter foster = 3 lives saved in Red Willow ❄️ (49) - Without emoji: One winter foster = 3 lives saved in Red Willow (47)
Option B (Action-led) - Subject: Open your home this winter for a Red Willow rescue pet (54) - Rationale: Direct, seasonal call to action that centers a specific next step. - Preheader: Short-term fosters in Red Willow County keep kennels open for emergencies. (74) - With emoji: Open your home this winter for a Red Willow rescue pet 🐾 (56) - Without emoji: Open your home this winter for a Red Willow rescue pet (54)
SECTION 2: 5 ADDITIONAL OPTIONS
1) Curiosity-led - Subject: What happens when one home opens up in winter? (46) - Rationale: Sparks curiosity that leads to the “3 emergency intakes” benefit.
2) Curiosity-led - Subject: Your winter roommate might have four paws… (42) - Rationale: Playful intrigue invites opens without giving away the ask.
3) Benefit-led - Subject: Foster by Nov 30 and make room for 3 emergency intakes (54) - Rationale: Deadline + clear outcome motivates timely action.
4) Action-led - Subject: Say yes to a 6–8 week winter foster in [ City ] (47) - Rationale: Plain-language next step with local relevance.
5) Personalized - Subject: [ First Name ], could you be a winter foster in [ City ]? (57) - Rationale: Name + city personalize the ask and increase relevance for locals. - Note: Use fallback “neighbor” if name/city missing.
SECTION 3: PREHEADERS FOR THE 5 ADDITIONAL OPTIONS
1) What happens when one home opens up in winter? - Preheader: One foster in Red Willow County creates space for 3 emergency rescues. (70)
2) Your winter roommate might have four paws… - Preheader: Try a 6–8 week foster and help us keep kennels open this winter. (64)
3) Foster by Nov 30 and make room for 3 emergency intakes - Preheader: Sign up by Nov 30 to free space for emergency intakes at Red Willow. (68)
4) Say yes to a 6–8 week winter foster in [ City ] - Preheader: Quick form, training provided, and supplies covered for winter fosters. (71)
5) [ First Name ], could you be a winter foster in [ City ]? - Preheader: We’ll match you with the right pet and support you every step. (62)
SECTION 4: SPAM & DELIVERABILITY CHECK
- Potential triggers: None of the subjects use FREE, URGENT, ACT NOW, $$$, ALL CAPS, or excessive punctuation. - Risk notes: - We used a single tasteful emoji in “with emoji” variants only (LIMITED policy). - We included a clear date (Nov 30, 2025) without shouting or gimmicks. - No exclamation marks, and language stays straightforward and nonprofit-appropriate. - Clean rewrites: Not needed; no flagged triggers present.
SECTION 5: A/B TEST RECOMMENDATION
- Test pair: Option A with emoji vs Option A without emoji. - Variable: Emoji vs none (single variable control). - Hypothesis: We predict the emoji version will lift opens because local, younger volunteers notice tasteful, relevant emoji; limited use can improve visibility without hurting deliverability. - Success metric: Open rate (target benchmark 20–25%+). Consider segmenting past adoption event attendees in Red Willow County for a likely higher baseline. - Tip: In Constant Contact, send to 10–20% sample first; declare winner after 2–4 hours; send the winner to the remainder.
SECTION 6: FROM NAME RECOMMENDATION
- Recommended options (STAFF-aligned): 1) Maya, Red Willow Animal Rescue 2) Foster Team at Red Willow Animal Rescue
- Why this fits: Casual, human sender names boost opens for volunteer asks; pairing a real staff name or small team name with the org builds trust while keeping it personal and mission-centered for a local audience.
AI Evaluation Details (Score: 9.2/10)
This output excellently matches the casual, local tone requested for a rural animal rescue. It delivers highly actionable, paste-ready content with strong nonprofit best practices. Minor weaknesses include a small formatting inconsistency in Section 2 and slightly generic phrasing in one curiosity line, but overall this is professional-grade work a small nonprofit could deploy immediately.
- • Perfect tone calibration: casual, warm, and community-focused without being unprofessional (e.g., 'Your winter roommate might have four paws…')
- • Strong local relevance throughout: 'Red Willow' appears in multiple subject lines, reinforcing geographic connection
- • Concrete, mission-aligned impact statements: '1 foster = 3 lives saved' is clear, memorable, and motivating
- • Excellent preheader strategy: each adds context without repeating the subject line, maximizing preview-pane real estate
- • Thoughtful personalization: Section 2 #5 correctly uses merge tags with fallback logic documented
- • Clean deliverability: no spam triggers, appropriate emoji use per LIMITED policy, professional language throughout
- • Actionable A/B test design: single-variable test (emoji vs none) with clear hypothesis tied to audience demographics
- • Practical From Name recommendations: 'Maya, Red Willow Animal Rescue' balances personal touch with organizational credibility
- • Character counts are accurate and well-optimized for mobile (most 42-57 characters)
- • Section 4 spam check is thorough and correctly identifies zero issues
- • Minor formatting inconsistency in Section 2 #4 and #5: uses '[ City ]' and '[ First Name ]' with spaces inside brackets, while the scenario specifies '[City]' and '[First Name]' without spaces—could cause merge-tag failures in Constant Contact
- • Section 2 #1 ('What happens when one home opens up in winter?') is slightly generic and could apply to many causes; more animal-specific language would strengthen authenticity
- • Section 6 could have included one additional tactical note about testing 'Maya' vs 'Foster Team' as a secondary variable for future campaigns
Mid-size Professional Org
Urban arts education nonprofit running a Giving Tuesday appeal to lapsed donors; warm, impact-forward.
View scenario details
SECTION 1: TOP 2 SUBJECT LINES (Ready to A/B test)
Option A - Subject: {{FirstName}}, $50 = a week of after-school art (47) - Rationale: Personalization plus a clear $50 impact creates ownership and clarity for lapsed donors. - Preheader: Sponsor one Baltimore student’s week of after‑school art by Dec 2. (66) - With emoji: {{FirstName}}, $50 = a week of after-school art 🎨 (49) - Without emoji: {{FirstName}}, $50 = a week of after-school art (47)
Option B - Subject: Giving Tuesday: what $50 does for one student (45) - Rationale: Curiosity hook leads into the concrete impact of a $50 gift. - Preheader: Hint: your gift today sponsors a week of after‑school art in Baltimore by Dec 2. (80) - With emoji: Giving Tuesday: what $50 does for one student 🎁 (47) - Without emoji: Giving Tuesday: what $50 does for one student (45)
SECTION 2: 5 ADDITIONAL OPTIONS
1) Your $50 sponsors a week of after‑school art (44) - Type: benefit-led - Rationale: Highlights the direct, tangible outcome of a $50 gift.
2) In Baltimore, $50 opens a week of art classes (45) - Type: benefit-led - Rationale: Adds local relevance while keeping the $50 impact front and center.
3) Give $50 today to sponsor a week of after‑school art (52) - Type: action-led - Rationale: Clear call to action with the exact gift amount and outcome.
4) Beat the Dec 2 Giving Tuesday deadline—give $50 (47) - Type: action-led - Rationale: Time-bound nudge tied to Giving Tuesday and a simple action.
5) See what your last gift sparked—and how $50 builds on it (56) - Type: curiosity-led - Rationale: Re-engages lapsed donors by connecting past impact to a specific next step.
SECTION 3: PREHEADERS FOR THE 5 ADDITIONAL OPTIONS
1) Your $50 sponsors a week of after‑school art - Preheader: On Giving Tuesday, your gift funds one student’s week of art in Baltimore by Dec 2. (83)
2) In Baltimore, $50 opens a week of art classes - Preheader: Help a Harbor Youth Arts student create after school—one week, one gift, by Dec 2. (82)
3) Give $50 today to sponsor a week of after‑school art - Preheader: Your Giving Tuesday gift brings paint, supplies, and guidance to one Baltimore student. (87)
4) Beat the Dec 2 Giving Tuesday deadline—give $50 - Preheader: Quick, meaningful gift: $50 sponsors one student’s after‑school art for a full week. (84)
5) See what your last gift sparked—and how $50 builds on it - Preheader: You helped us light a creative spark. This Giving Tuesday, $50 keeps it shining. (80)
SECTION 4: SPAM & DELIVERABILITY CHECK
- Potential triggers flagged: None. We avoided ALL CAPS, FREE, URGENT, ACT NOW, multiple punctuation (!!!/???), and excessive emojis. - Currency symbol ($) and an em dash (—) are generally safe; we used one emoji only in A/B variants per LIMITED policy. - Personalization note: Ensure {{FirstName}} has a fallback of “friend” to prevent empty tags. - No rewrites needed.
SECTION 5: A/B TEST RECOMMENDATION
- Test these two: - Variant 1 (personalized/benefit): {{FirstName}}, $50 = a week of after-school art - Variant 2 (generic/curiosity): Giving Tuesday: what $50 does for one student - Variable: personalized vs generic - Hypothesis: We predict personalized will perform better because lapsed donors are more likely to re-engage when they see their name and a clear, concrete impact. - Success metric: Open rate (aim for 20–25% benchmark; lapsed segment may run lower—consider a resend to non-openers with the winning line).
SECTION 6: FROM NAME RECOMMENDATION
- Primary: Maya Thompson at Harbor Youth Arts - Alternate: Marcus Lee, Harbor Youth Arts
Why this fits: A real staff name plus the organization builds trust and warmth for an appeal, especially with lapsed donors, while keeping Harbor Youth Arts recognizable in the inbox.
AI Evaluation Details (Score: 8.4/10)
This output is highly professional and actionable, delivering subject lines that appropriately balance warmth, clarity, and impact messaging for a lapsed donor audience. The structure is complete and follows the template precisely, though there are minor inconsistencies in the from-name section. The content would be immediately usable by a nonprofit communications team.
- • Excellent character count discipline—all subject lines fall within the 40-60 character sweet spot, with accurate counts provided throughout
- • Strong personalization strategy that appropriately targets lapsed donors with concrete impact messaging ($50 = 1 week) rather than guilt-based appeals
- • Well-constructed A/B test recommendation with a clear hypothesis grounded in audience psychology and a realistic acknowledgment that lapsed segments may underperform benchmarks
- • Preheaders consistently add context without repeating subject lines, and effectively incorporate location (Baltimore) and deadline (Dec 2) where relevant
- • Spam/deliverability check is thorough and correctly identifies no major triggers; appropriate use of LIMITED emoji policy
- • Good mix of subject line types across the seven options (benefit-led, action-led, curiosity-led, personalized) as specified
- • Section 6 from-name recommendation introduces two new staff names (Maya Thompson, Marcus Lee) that don't match the scenario input which specified 'Alicia Bennett' as the staff/CEO name—this creates confusion and would require the user to substitute the correct name
- • Option B's preheader in Section 1 uses 'Hint:' which, while not spam-triggering, feels slightly gimmicky for a warm tone and lapsed donor audience—a more straightforward approach might be stronger
- • The curiosity-led option in Section 2 (#5: 'See what your last gift sparked') assumes the lapsed donor will remember their previous gift, which may not resonate if they gave 24-36 months ago; this could have been flagged as a potential risk
Large Established Org
National environmental NGO mobilizing a formal advocacy alert around federal water protections; policy-engaged audience.
View scenario details
SECTION 1: TOP 2 SUBJECT LINES (Ready to A/B test)
Option A - Subject (42): Please sign to defend the Clean Water Rule - Rationale: Action-led and explicit about the policy at stake to drive immediate signatures. - Preheader (71): Add your name by Dec 15 to keep the Clean Water Rule strong nationwide. - Emoji version: Not provided (Emoji policy: NONE)
Option B - Subject (40): Every 50 signatures alerts key lawmakers - Rationale: Benefit-led; quantifies impact to show how each signature moves Congress. - Preheader (89): Your signature helps trigger targeted alerts to lawmakers; every 50 counts by Dec 15. - Emoji version: Not provided (Emoji policy: NONE)
SECTION 2: 5 ADDITIONAL OPTIONS
1) Type: curiosity-led - Subject (49): What happens if we miss the December 15 deadline? - Rationale: Opens a question to spur timely action before the cutoff.
2) Type: curiosity-led - Subject (51): Your signature could be the 50th to notify Congress - Rationale: Creates tension around being the next milestone that triggers outreach.
3) Type: action-led - Subject (46): Add your name by Dec 15 to protect clean water - Rationale: Direct call with deadline and clear purpose.
4) Type: benefit-led - Subject (53): Each 50 signatures triggers a targeted lawmaker alert - Rationale: Highlights the concrete advocacy mechanism supporters enable.
5) Type: personalized - Subject (57): [firstname], your signature protects the Clean Water Rule - Rationale: Formal, respectful personalization that ties the action to the specific rule. Note: Uses Campaign Monitor tag [firstname] with fallback “supporter”
SECTION 3: PREHEADERS FOR THE 5 ADDITIONAL OPTIONS
1) What happens if we miss the December 15 deadline? - Preheader (75): Add your name today so Congress hears from you before the rule is weakened.
2) Your signature could be the 50th to notify Congress - Preheader (70): Your name may be the tipping point that triggers outreach to Congress.
3) Add your name by Dec 15 to protect clean water - Preheader (73): Sign the Global Water Trust petition; every 50 names alert key lawmakers.
4) Each 50 signatures triggers a targeted lawmaker alert - Preheader (73): Help us reach the next 50 by December 15 to protect the Clean Water Rule.
5) [firstname], your signature protects the Clean Water Rule - Preheader (80): Add your name today; policy staff in Washington will deliver alerts to Congress.
SECTION 4: SPAM & DELIVERABILITY CHECK
- Potential triggers found: None. No ALL CAPS, “FREE,” “URGENT,” “ACT NOW,” or excessive punctuation. - Clean rewrites: Not needed. - Mitigations used: Kept tone formal, avoided hype language, limited punctuation, front-loaded key terms (Clean Water Rule, signatures, deadline).
SECTION 5: A/B TEST RECOMMENDATION
- Test these two: • Option A (action-led): Please sign to defend the Clean Water Rule • Option B (benefit-led): Every 50 signatures alerts key lawmakers - Variable: Benefit-led vs action-led - Hypothesis: Benefit-led will outperform because policy-engaged supporters respond to quantified impact (every 50 signatures triggers a lawmaker alert). - Success metric: Open rate (target ≥20–25% benchmark). Consider that a national, policy-engaged list may skew higher; send to a 10–20% test segment first, declare winner after 2–4 hours, then send the winner to the remainder.
SECTION 6: FROM NAME RECOMMENDATION
- Primary: CEO, Global Water Trust - Alternate: Office of the CEO, Global Water Trust Note: A CEO-anchored from name lends authority and aligns with a formal advocacy alert to policy-engaged partners, signaling institutional credibility without over-personalization.
AI Evaluation Details (Score: 8.8/10)
This output demonstrates excellent understanding of formal advocacy communications and delivers highly usable, professional subject lines. The tone is appropriately formal without being stiff, and the benefit-led framing (50 signatures = lawmaker alert) is strategically sound for policy-engaged audiences. Minor deductions for a few character-count inconsistencies and one slightly long personalized subject line.
- • Perfect tone calibration: formal, clear, respectful language appropriate for policy-engaged national audience without jargon or emotional manipulation
- • Strong strategic framing: the '50 signatures = lawmaker alert' mechanism is concrete, credible, and motivating for advocacy-savvy supporters
- • Excellent spam avoidance: completely clean of triggers while maintaining urgency through deadline and specific policy reference
- • Smart A/B test design: benefit vs. action is a meaningful variable with a well-reasoned hypothesis grounded in audience characteristics
- • Appropriate CEO from-name recommendation with clear institutional rationale for formal advocacy context
- • All 7 subject lines are genuinely distinct and usable, not just minor variations
- • Preheaders consistently add context without repetition and stay within character limits
- • Minor character count discrepancy: Section 1 shows '(42)' and '(40)' but actual counts are 43 and 40 respectively when measured precisely
- • Personalized subject line in Section 2 (#5) is 57 characters—pushes upper limit and may truncate on mobile; could be tightened
- • The alternate from-name 'Office of the CEO' feels slightly bureaucratic; 'Dr. Lena Cho, Global Water Trust' would be warmer while maintaining formality
- • Curiosity-led option #1 ('What happens if we miss...') borders on fear-based framing, which may feel slightly off-tone for this formal context, though still acceptable
Test Summary: Generated Nov 2, 2025 • 3 scenarios • 9 total outputs • Average quality score: 8.42/10 • Total validation cost: $0.4697