Character Counter Calculator
Count user-perceived characters and compare them with reference limits. SMS segments account for GSM-7 or Unicode capacity; platform limits and URL weighting can differ from these estimates.
Last updated · View algorithm, constants and default inputs (JSON)
About this calculator
Count user-perceived characters and compare them with reference limits. SMS segments account for GSM-7 or Unicode capacity; platform limits and URL weighting can differ from these estimates.
Worked example
calculated with the default values below
Character limit to check against 280 chars · Platform X / Twitter post (280) · Words 50 words Characters with spaces 255 chars · Characters without spaces 205 chars · Words 50 words · Reference limit / SMS units 280 chars · Characters remaining 25 chars · Status Fits, but close to the limit · SMS segments 2
General background references
Disclaimer
These calculators give general date results. Public holidays, working-day conventions and time-zone rules are set locally and change, so confirm against the official calendar for anything legally or contractually binding.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
N_SMS = GSM7 units/160 or 153; Unicode UTF-16 units/70 or 67
- n
- Characters (trimmed)
- L
- Platform character limit
- R
- Characters remaining
- N_SMS
- SMS segments
Grapheme clusters count visible characters. SMS uses GSM-7 (160/153 units) or Unicode UTF-16 (70/67 units); platform presets are reference values.
Frequently asked questions
How are SMS segments estimated?
GSM-7 basic characters use one unit, extension characters two (160 units for one segment, 153 concatenated). Unicode SMS uses 70 UTF-16 units, or 67 concatenated. Carrier behavior can vary.