How long will the browser take to read that aloud?
Browsers can read text aloud through the Web Speech API — no audio file, no upload, the voice comes from your own operating system. Before you use it to proof-read a paragraph or check how a script will sound, it helps to know how long that playback will actually take, and that's one division, not a guess.
The method
- Count the words in the text (a word counter, or just count them).
- Pick a speaking rate in words per minute. Conversational narration is commonly estimated at 130–170 words per minute; 150 is a reasonable middle rate for clear, measured speech.
- Divide the word count by the rate to get minutes. Multiply by 60 for seconds.
A worked example
Take a paragraph of 150 words — about the length of a short product description.
- At 130 wpm (slower, deliberate pace): 150 ÷ 130 = 1.154 minutes = 69 seconds.
- At 150 wpm (middle pace): 150 ÷ 150 = 1.000 minute = 60 seconds.
- At 170 wpm (brisker pace): 150 ÷ 170 = 0.882 minutes = 53 seconds.
So the same 150-word paragraph takes anywhere from 53 to 69 seconds depending on the voice and the rate it's set to speak at — roughly a 16-second spread, which matters if you're timing a video voiceover or a kiosk announcement against a fixed slot.
Why the range, not a single number
A browser's text-to-speech rate isn't fixed: most expose a speed control, and different system voices read at different default paces even at "normal" speed. That's why one honest estimate is really three numbers — a floor, a middle and a ceiling — rather than a single confident guess. If you need to hit a precise duration, test the actual voice and rate you'll ship with rather than trusting any average.
Why this is worth knowing
Text-to-speech is also an accessibility feature, not just a convenience — it's how some readers access written content at all. Estimating playback time before you publish means captions, slide timing and kiosk scripts can be written to actually fit the audio instead of being guessed at and fixed after the fact.