I built a free character counter that handles X's weighted length and SMS segments

I kept hitting the same problem: a draft that looked short enough would get
rejected by X, Instagram or an SMS gateway. Each platform counts characters
differently, and most counters only give you one number.

So I built CharCountLab, a small static site with four focused tools:

• Character Counter: characters with and without spaces, words, sentences, paragraphs, reading and speaking time
• Twitter Character Limit: X's weighted length (URLs cost 23, emoji and CJK cost 2) against the 280 limit
• Instagram Caption Character Limit: 2,200 characters plus hashtag and mention counts
• SMS Character Limit: GSM-7 vs Unicode, 160 / 153 / 70 / 67, and how many segments you'll be billed for

Everything runs in the browser. No signup, no upload, no tracking — your text
never leaves the device. The pages are plain HTML with the content in the
source, so they are readable without JS and need no build step.

A few things I learned while building it:

• One emoji flips an entire SMS from GSM-7 (160 chars) to Unicode (70), doubling the cost
• Instagram collapses captions after about two lines, so the first 125 characters matter more than the 2,200 limit
• A URL in an X post always costs 23 characters, however long the link is

Try it: https://charcountlab.pages.dev/

If you've run into a counting rule I've missed, I'd love to hear about it.