Syllable counter
Type something and the most frequent words show up here.
Syllables are estimated by counting vowel groups and discarding a silent trailing "e". That is right for the large majority of ordinary English words and wrong for a stubborn minority — which is a limit of English spelling, not of the tool.
How to count syllables
No algorithm gets this exactly right, because English spelling does not determine syllable count. The vowel-group rule handles "com-pu-ter" and "ta-ble" correctly and then fails on the standard counterexamples: "business" is two syllables but scans as three, "poem" is two but looks like one, and "fire" divides differently depending on the accent saying it. Dictionaries disagree with each other on a surprising number of words for the same reason. Treat the number as a fast approximation for readability work and as a starting point for anything metrical, where your ear is the authority.
Questions
Good on the large majority of ordinary words and wrong on a stubborn minority. Words like "business", "poem" and "fire" defeat every spelling-based rule.