How sentences are detected
A sentence ends at a period, question mark, or exclamation point followed by a space, or at a line break. Abbreviations such as “e.g.” can occasionally be counted as a sentence end, so treat the count as a close estimate.
Reading and speaking time
Reading time assumes 238 words per minute, the average silent reading speed measured for adults reading non-fiction in English. Speaking time assumes 130 words per minute, a comfortable pace for a presentation.
Sentence length
Average sentence length is a quick readability check. Plain-language guides commonly suggest averaging 20 words or fewer per sentence for web and business writing.
Character limits worth knowing
Many places count characters rather than words. Posts on X allow 280 characters for most accounts. A standard SMS holds 160 characters, but only 70 if it contains an emoji or other characters outside the basic set, after which the message is split. Search engines usually show around 150 to 160 characters of a meta description before cutting it off. The character counts above include spaces; use “Characters without spaces” when a form asks for that instead.
Using sentence length to edit
An average of 15 to 20 words per sentence is easy to follow for most readers. If your average is higher, look at your longest sentence first: it is usually two ideas joined with “and” or “which”, and splitting it is the quickest readability win. Variety matters too, so a short sentence after a long one helps a point land.