# How long will this audiobook take?

Computes how long an audiobook takes to hear at a playback speed, the time saved, and how many days it takes at a daily listening time, from its length or from a word count.

- Page: https://www.acalculator.org/everyday-life/audiobook-length-calculator
- JSON spec: https://www.acalculator.org/everyday-life/audiobook-length-calculator.json
- Version: 87abc839efcf

## Default answer

Example with the default inputs (I know Its length, Hours 11, Minutes 30, Playback speed 1.5, Minutes a day 45): At 1.5× the audiobook takes 7 hours, 40 minutes.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| know | I know | The length of the audiobook, or the number of words in the book. |
| h | Hours | The hours part of the audiobook’s length at normal speed. |
| m | Minutes | The minutes part of the audiobook’s length at normal speed. |
| words | Words | The number of words in the book. |
| speed | Playback speed | The speed you listen at, such as 1.5 for 1.5×. |
| daily | Minutes a day | How many minutes you listen each day. Leave empty to skip the days. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| listening | Listening time | The length at normal speed ÷ the playback speed. |
| saved | Time saved | The length at normal speed minus the listening time, when you listen faster than 1×. |
| added | Time added | The listening time minus the length at normal speed, when you listen slower than 1×. |
| length | Length at 1× | The length at normal speed, given or worked out from the words at 9,300 words an hour. |
| days | Days to finish | The listening time in minutes ÷ the minutes a day, rounded up to whole days. |

## Method

listening time = length ÷ speed; length from words = words ÷ 9,300 an hour; days = ⌈listening minutes ÷ minutes a day⌉

## Assumptions

- A word count becomes a length at 9,300 words per finished hour, the average ACX gives for narrators. Narrators differ.
- Times are shown to the nearest second (a half second rounds up). Time saved or added is the difference of the two rounded times.
- Days to finish round up, so the last day may be short.

## Worked examples

1. know = length, h = 11, m = 30, speed = 1.5, daily = 45 gives listening = {"hours":7,"minutes":40,"seconds":0}, saved = {"hours":3,"minutes":50,"seconds":0}, days = 11. Source: hand calculation in content.mdx: 11.5 h ÷ 1.5 = 7 h 40 min; 11 h 30 min − 7 h 40 min = 3 h 50 min; 460 ÷ 45 = 10.2, so 11 days.
2. know = words, words = 93,000, speed = 1 gives length = {"hours":10,"minutes":0,"seconds":0}, listening = {"hours":10,"minutes":0,"seconds":0}. Source: ACX: about 9,300 words per finished hour; hand calculation in content.mdx: 93,000 ÷ 9,300 = 10 h.
3. know = length, h = 9, m = 5, speed = 1.75, daily = 30 gives listening = {"hours":5,"minutes":11,"seconds":26}, days = 11. Source: hand calculation in content.mdx: 545 min ÷ 1.75 = 311.43 min = 5 h 11 min 26 s; 311.43 ÷ 30 = 10.4, so 11 days.
4. know = length, h = 2, m = 0, speed = 0.8 gives listening = {"hours":2,"minutes":30,"seconds":0}, added = {"hours":0,"minutes":30,"seconds":0}. Source: hand calculation in content.mdx: 2 h ÷ 0.8 = 2.5 h, 30 minutes more.

## FAQ

### How long is an audiobook at 1.5× speed?

Divide the length by 1.5. An 11 h 30 min audiobook takes 11.5 ÷ 1.5 = 7.67 hours, or 7 h 40 min, which saves 3 h 50 min.

### How many words are in an hour of audiobook?

ACX, Audible’s audiobook production marketplace, says narrators average about 9,300 words per finished hour. A 93,000-word novel is about 10 hours at 1×.

### How do I estimate an audiobook’s length from a book?

Choose Word count and enter the words. The length at 1× is words ÷ 9,300 hours. Page counts are less reliable, because words per page vary with the font and layout.

### How many days will it take me to finish?

Enter how many minutes a day you listen. The calculator divides the listening time in minutes by that and rounds up. 460 minutes at 45 minutes a day is 10.2, so 11 days.

### Does slower playback add time?

Yes. At 0.8× a 2 hour audiobook takes 2 ÷ 0.8 = 2.5 hours, 30 minutes more. The calculator shows this as time added.

### Is the length on the store page at 1×?

Yes. Stores list the length of the recording at normal speed. The listening time here is that length divided by your speed.

## Sources

- ACX (Audible), Narrate an audiobook: narrators average about 9,300 words per finished hour. https://help.acx.com/s/article/producing-and-recording-your-audiobook