Measure Character Limits for Forms and SMS-Style Messages

When this applies

Reach for this flow when UX copy must fit a VARCHAR or when carriers charge by segment. Characters-with-spaces and without often differ enough to break validators that engineers configured years ago without telling marketing.

Tool to use

Count characters with and without spaces.

Open Character Counter →

Steps

  1. 1Paste the exact string users will submit, including emoji if you allow them.
  2. 2Compare both character modes against backend documentation.
  3. 3Spot multi-codepoint emoji that look like one glyph on phones.
  4. 4If encoding matters, validate UTF-8 byte length in engineering staging too.

Examples

  • OTP SMS templates must stay in one GSM-7 segment when possible.
  • Bio fields on a government portal reject overlong Unicode names.

What to avoid

  • Trusting Twitter/X preview without counting edited.alt text separately.
  • Ignoring trailing newlines accountants paste from Excel.
  • Testing only ASCII while real users paste smart quotes.

Related tools

On the blog

More in Text Tools

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FAQ

SMS length rules?

Encoding and concatenation vary by carrier toolkit—count here, then verify in the SMS provider sandbox.

Tabs?

Tabs count as characters; normalize if your form forbids them.

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