How to get the most out of the email subject line generator
This tool works best when you give it context and use the outputs as a starting point, not a final draft.
Start with body text when you already have a draft
If you've written your email, paste the body text instead of summarizing it in the topic field. The tool pulls key points and benefit statements directly from your copy, which produces subject lines that match what's inside the email.
This is especially useful for newsletters and product announcements where the body is set and you need a subject line that accurately teases the content. You'll get options that reflect the actual message, not a vague approximation.
Use tone to match the campaign type
Professional and formal tones work for B2B outreach, internal comms, and anything that needs to sound authoritative. Casual and playful tones fit consumer brands, lifestyle products, and audiences that expect personality. Bold works for launches and time-sensitive offers.
Run the tool twice with different tones if you're unsure. Compare the outputs and you'll quickly see which style fits your brand and the specific campaign.
Turn off emoji for deliverability-sensitive sends
Emoji can lift open rates in consumer emails but they can also trigger spam filters or look unprofessional in B2B contexts. If you're sending to a corporate audience or a cold list, leave emoji off.
For warm audiences and consumer brands, test emoji-on versions in your A/B tests. The tool generates emoji that match the subject line content, so they feel intentional rather than random decoration.
Add the tool to a Letaido workspace for unlimited runs and brand voice
The free version gives you three runs per day. A Letaido workspace removes that limit and lets you set a custom brand voice so every subject line matches your style without extra prompting. You can also chain the tool with others: generate email body copy, then pass it to the subject line tool in one workflow.
If you're writing multiple emails a week, a workspace saves time and keeps your tone consistent across campaigns.