Use word count when you are estimating reading length or meeting an essay target. Use character count when a form, title, bio, or message has a hard character limit. The destination's own counter is authoritative for that field.
Check whether spaces, punctuation, line breaks, emoji, and combined Unicode characters count the way you expect. Some platforms limit bytes or code units rather than what a person sees as one character. A word counter or character counter is useful for drafting, but paste the final text into the target field to verify it fits.
Leave a little room for later edits rather than writing exactly to the edge.
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