In a crowded inbox, your subject line is your one chance to capture attention. This free tool analyzes your subject line against proven marketing data, giving you an instant score and AI-powered advice to turn a good subject line into a great one.
Type or paste the subject line you want to analyze into the tool above.
Select the purpose of your email (e.g., B2B outreach, B2C promotion). Our AI adjusts its advice based on your goal.
Instantly receive a score out of 100, a detailed analysis, and AI-powered suggestions to improve it on the spot.
We check character and word counts to ensure your message is concise and avoids being cut off on mobile devices, where over half of all emails are read.
Ideal: 20-60 characters & 3-9 words.
The words you choose create an emotional response. Our tool checks for:
In a busy inbox, your subject line needs to be easy to read. We check for capitalization style, and strategic use of numbers and emojis to make it stand out.
A subject line for a cold B2B email should be different from a B2C promotional blast. Our tool adjusts its recommendations based on the context you provide.
Don’t give everything away. Instead of “Our new guide to email marketing,” try “The one thing you’re missing in your emails.”
Phrases like “last chance” or “24 hours left” are powerful, but should only be used when they are authentic to avoid audience fatigue.
Go beyond just {FirstName}. A subject line like “A question about Warmup Inbox” for a B2B lead is far more effective than a generic one.
The only way to truly know what works for your audience is to test. Pit two subject lines against each other and let the data choose the winner.