The most useful way to estimate narration length is words per minute. If your voice averages 140 words per minute, a 1,400-word script is roughly ten minutes before extra pauses and edits.
Delivery style changes timing
Fast short-form narration may fit more words into a minute. Documentary narration, storytelling, tutorials, and emotional delivery may use more pauses and therefore fewer words.
Why page count is unreliable
Font size, spacing, margins, dialogue formatting, and headings all change the number of words on a page. Word count is much more consistent.
Plan for editing
Visual beats, reaction moments, music transitions, and intentional silence can make the finished video longer than the raw spoken-word estimate.
Use the estimator
Open the Voiceover Duration Calculator and test several speaking speeds.