Email subject line tester for cold email.
Type a subject line and get a score as you type: length, spam words, punctuation, tone and personalization, plus a preview of how it shows in a phone and a desktop inbox.
Scores as you type. Nothing you write leaves your browser.
Cold subjects play by different rules.
Most subject line testers are built for newsletters, where the reader asked for the email and a hook or an emoji helps it stand out. A cold email goes to one person who has never heard of you. The subjects that get opened there look like they came from a colleague: short, lowercase or sentence case, specific, and calm.
So this tester rewards the opposite of a headline. {{first_name}}, quick idea scores near the top. FREE Demo: Boost Your Sales 300%!! scores near the bottom, for six separate reasons it lists.
What we score.
- Length. Two to five words is the target. Past about 38 characters a phone inbox cuts the line off, and long subjects read like marketing.
- Spam and sales words. The same lexicon as our email spam checker: urgency, money, hype, pushy calls to action and scam language.
- Fake threads. Re: or Fwd: on a first email can win an open and lose the reply, and misleading subject lines are against US law (CAN-SPAM).
- Shouting and symbols. Words in capitals, exclamation marks, stacked question marks, prices and percentages.
- Tone. Emoji and Title Case Every Word mark an email as a campaign, not a note.
- Personalization. A merge tag such as
{{company}}is the cheapest proof the email was not a blast.
Examples, good and bad.
| Subject | Why |
|---|---|
{{first_name}}, quick idea | Short, personal, low pressure. |
{{company}} hiring | Specific to them and reads like an internal note. |
question about the Austin office | Specific, and lowercase looks typed by a person. |
Unlock Your Team's Full Potential Today | Title Case, hype, says nothing about the reader. |
Re: our conversation | There was no conversation. Readers notice. |
FREE trial, limited time!! | Spam words, capitals and exclamation marks. |
More free tools.
SPF, DKIM & DMARC Checker
Enter a domain and see whether its MX, SPF, DKIM and DMARC records are ready for cold email, with the exact record to publish for anything missing.
Email Spam Checker
Paste a cold email and see the spam words, formatting and sentences that push it toward the spam folder, with a predicted inbox placement.
Questions,
answered.
Two to five words, and under about 40 characters so a phone inbox shows it in full. Short subjects look like a note from a colleague, which is what gets a cold email opened.
A first name or company name is a cheap signal that the email was written for them and not blasted to a list. Use it in some variants, not every email in the sequence, and make sure the merge field is filled for every lead.
No. It pretends a conversation already exists. It can lift opens, but readers notice and reply less, filters treat it as a spam pattern, and misleading subject lines are against CAN-SPAM in the US.
Not in cold email. Emoji and Title Case Every Word are newsletter conventions, so they mark the message as marketing. Capitalized words read as shouting and are a classic spam tell.
Yes, as part of the whole email. Spam words, symbols and capitals in the subject add to the signals filters weigh. Run the full email through the email spam checker and your domain through the SPF, DKIM and DMARC checker to cover the rest.
No. The score is calculated in your browser as you type. Nothing is sent to a server or stored.
Pick the winner
with real replies.
FoxReach splits a campaign step into subject variants and tracks opens and replies for each, so the next send uses the line that worked.