TTS reading speed calculator
How long will your script be once it is read aloud? Whether you are filling a podcast slot, a video voiceover, or an audiobook chapter, audio duration comes down to word count, speaking rate, and pauses. This calculator converts your words into an estimated duration at slow (≈120 wpm), normal (≈150 wpm), or fast (≈190 wpm) rates, with a pause adjustment.
How it works
The base estimate is simple, then pauses are layered on:
base_minutes = words / words_per_minute
pause_minutes = sentences × pause_seconds / 60
duration = base_minutes + pause_minutes
A “normal” TTS read sits around 150 words per minute, matching a typical human narrator. Bumping a TTS engine’s speed parameter to 1.2 is roughly the same as choosing the fast rate here, while 0.8 maps to slow.
Tips for hitting your target length
- Plan backwards from the slot. A 60-second ad at normal pace is about 150 words — write to that, then trim.
- Pauses add up fast. A one-second beat after every sentence in a 30-sentence script adds half a minute on its own.
- Slow down for instructions. Step-by-step content reads clearer at 120–130 wpm; rushing it hurts comprehension.
- Verify the final render. Numbers, acronyms, and SSML breaks shift real duration — confirm against an actual generation for tight broadcast windows.