EmailSubjectScore Pro vs Sendcheckit

Free Chrome extension that scores Gmail subject lines live as you type — vs Sendcheckit, the free web-based tool. Side-by-side comparison.

If you write more than a few emails a week and want scoring inside Gmail without switching tabs, EmailSubjectScore Pro is the better fit. Sendcheckit is fine for occasional one-off checks — but honestly, copying your subject line to another tab every single time gets old fast.

Side-by-side

	EmailSubjectScore Pro	Sendcheckit
Where it lives	Inside your Gmail compose window	Separate web page (sendcheckit.com)
Real-time scoring	✅ Scores as you type	❌ Paste and click
AI rewrite suggestions	✅ One-click rewrites	❌ Score only
Dimensions scored	Spam risk, Clarity, Urgency	Overall “score” only
Free tier	50 scores/month	Unlimited (browser-only)
Requires signup	❌ No signup needed	❌ No signup needed
Works with dark mode	✅	N/A
Cost	Free (Pro tier planned)	Free
Installation	Chrome Web Store	None (web tool)

So which one fits your workflow?

Pick Sendcheckit if you write emails elsewhere (Outlook, Superhuman, mobile) and just need a quick browser tab to paste into once in a while. One subject, one check, done.

Pick EmailSubjectScore Pro if Gmail is where you actually compose. You send a bunch of emails per day — cold outreach, sales, whatever — and switching tabs to score each one is just… not something you’re going to keep doing. You also get AI rewrites, which Sendcheckit doesn’t do at all.

The scoring difference

Both tools look at spam-trigger words, punctuation, length. Standard stuff. But Sendcheckit gives you one number. Score only. No context. Just a number.

EmailSubjectScore Pro breaks it into three dimensions — spam risk, clarity, urgency — so you actually know what to fix. And if you don’t feel like fixing it yourself, hit “Suggest rewrite” and it’ll give you a version that scores higher. Lazy? Maybe. But it works.

Try it free

Install EmailSubjectScore Pro from the Chrome Web Store →

No signup. Free forever tier includes 50 scores/month + rewrites.

Full disclosure: this comparison is written by the team behind EmailSubjectScore Pro. Sendcheckit is an independent tool by its own creator — we recommend both for different use cases.