A YouTube video length calculator is a tool that estimates how long a video will run — before you record it — based purely on your script’s word count and a chosen narration speed.
Instead of guessing, or timing yourself reading the script out loud, you paste the text in, pick a speaking pace, and get an instant estimate in minutes and seconds.
Why creators use one
Planning a video’s runtime matters more than most new creators expect:
- Ad placement — YouTube fits mid-roll ads more naturally into videos between 8 and 15 minutes long.
- Retention planning — a script that looks short on the page can turn into a 12-minute video once it’s read aloud.
- Voiceover and AI narration — AI voice tools read at a fairly consistent words-per-minute rate, so word count reliably predicts runtime.
- Multi-platform repurposing — creators cutting a script down into a Short need to know exactly how much to trim.
How the calculation works
Video length (seconds) = (word count ÷ words per minute) × 60
Slow pace is around 130 words per minute, normal pace around 150, and fast pace around 170. A 1,500-word script at normal pace comes out to roughly 10 minutes — right in the ad-friendly zone.
What it doesn’t account for
A calculator estimates spoken time only. Your final video is usually a little longer once you add intro/outro music, pauses for emphasis, B-roll with no narration, and transitions. Add a 5–10% buffer for editing.
Try it
Use the free YouTube video length calculator — paste your script, pick a pace, and get your runtime instantly.