Subject Line Length Analyzer — Where Each Client Cuts You Off
Who this is for: For anyone who wrote a beautiful line and discovered in their own inbox that subscribers only ever saw half of it.
See exactly where Gmail, Outlook, Yahoo and Apple Mail cut your line — and the character band that fits.
Quick answer: Clients show roughly: Gmail app 35 · Outlook 45 · Yahoo 60 · Apple Mail 65 · Gmail web 70 characters. The safe band is 26–50 characters with the point in the first four words — paste your line to see each client's cut rendered.
Subject line character limits by client (approximate)
| Client | Visible characters | What it means |
|---|---|---|
| Gmail — mobile app | ~35 | the tightest pane; more than half of opens happen here |
| Outlook — desktop | ~45 | the B2B surprise; many business lists skew here |
| Yahoo Mail | ~60 | mid-band; two-line layouts vary |
| Apple Mail — iPhone | ~65 | wider, but MPP auto-opens mean fewer real eyes |
| Gmail — desktop web | ~70 | the widest common pane |
Figures are engineering approximations — devices, fonts and zoom shift them. The safe band is 26–50 characters with the point in the first four words. The tester below renders your line against every cut.
Rendered as each client shows it
Trim suggestion: keep the first clause (“Your fall guide is here: 12 rooms,”) — the point already survives; the tail is what panes eat.
Approximations by design: foldables, font settings and zoom shift each client's real cut. The habit that survives every client — front-load the point in the first 3–4 words.
| Client cuts | Gmail 35 · Outlook 45 · Yahoo 60 · Apple 65 · Gmail 70 |
|---|---|
| Sweet band | 26–50 chars · 4–8 words |
| Technical max | ~980 chars — irrelevant, panes cut first |
| Rule | Front-load: first 3–4 words are guaranteed |
| Caveat | Approximations — devices/fonts/zoom shift them |
| Status | Rules follow public email-marketing benchmark practice (2026): ~35–70 visible characters by client, 175-word spam trigger list, sentence case, one clear idea per line. Client truncation figures are engineering approximations — devices, fonts and zoom shift them. |
How long can an email subject line be?
Technically up to ~980 characters; practically, each client shows what fits its inbox pane — roughly 35 characters in the Gmail mobile app, 45 in Outlook desktop, 60 in Yahoo, 65 in Apple Mail on iPhone, and about 70 in Gmail on the desktop web. (These are engineering approximations: foldable phones, font settings and zoom all nudge them.) The analyzer counts your characters and words, renders the cut for each client so you see the truncated line as your subscribers will, and flags the 26–50 band as the sweet spot — long enough to make the case, short enough to survive the smallest pane. Front-load the point: most truncation happens from the right, so the first three or four words are the only ones guaranteed seen.
Common uses
- Checking the mobile cut before sending to a phone-heavy list
- Deciding what belongs in the subject vs the preheader
- Re-writing long lines by moving the point to the front
- Setting a house style: the band your team's lines should land in
Frequently Asked Questions
What is the best length for an email subject line?
How many characters does Gmail show?
How many characters does Outlook show?
Do subject lines get truncated or wrapped?
What about emojis and character counting?
More guides
11 cold email subject lines that earn the open — organized by play, with the scored engine results and what to steal from each.
Subject line plays for newsletters specifically — habit, naming conventions, issue numbering, and 12 scored examples.
The seven-step process for writing subject lines that get opened — draft, check, trim, preview — with the ten checks that matter in 2026.
More Deliverability checkers
Scan your subject line against 175 spam trigger words — high-risk and medium-risk flagged, with fixes.
Two lines side by side — scores, check-by-check differences, and the verdict on which to send.
Subject + preheader rendered as Gmail desktop, Gmail mobile and Outlook will show them — before you send.