Audiobook Speed Calculator

1. Enter the audiobook length in hours and minutes. Use the time remaining for a book you have already started.
2. Type your playback speed. Any value works, including 1.1, 1.35 or 2.75.
3. Add your daily listening minutes to see the days to finish and the date you reach the end.

Audiobook playback speed is the multiplier a player applies to the normal rate of the recording. A speed of 1 is the rate the narrator recorded. A speed of 2 plays twice as fast, so the book lasts half as long.

The web standard for media players describes it the same way. The normal playback rate is multiplied by the speed value, and 1.0 means normal speed. Players also correct the pitch by default, so a faster voice does not sound higher.

Speed control is not new. The free talking-book players that the US National Library Service lends to eligible readers include variable speed controls as a standard feature.

This calculator covers the arithmetic only. It tells you how long a book takes at a speed. It cannot tell you which speed you will follow comfortably.

Listening time equals the book length divided by the playback speed. Everything else on the page follows from that one division.

1. Turn the length into minutes: 10 h 30 min is 630 minutes.
2. Divide by the speed: 630 / 1.5 = 420 minutes, which is 7 hours.
3. Subtract from the original to get the saving: 630 - 420 = 210 minutes, or 3 h 30 min.
4. Divide the listening time by your daily minutes and round up: 420 / 60 = 7 days.

The saving is not the same as the speed increase. A 50 percent faster speed removes one third of the time, not one half.

A 12 hour 45 minute novel at 1.25x. The length is 765 minutes. Divide by 1.25 to get 612 minutes, or 10 h 12 min.

The saving is 765 - 612 = 153 minutes, which is 2 h 33 min, or 20 percent of the book.

At 45 minutes of listening a day, 612 / 45 = 13.6, so the book takes 14 days. With a 150 wpm narrator, 1.25x plays at about 188 words per minute.

To turn a finish date into a calendar plan, the date calculator adds or subtracts days from any date.

The Length You Start From

Store listings give the full length. Your app usually shows time remaining. Enter the remaining time for a book in progress, or the result will overstate what is left.

Whether Your App Already Adjusts the Display

Some apps show time remaining at your current speed and others show it at 1x. Check which one you are reading before you divide again.

Speed Changes During the Book

The calculation assumes one speed from start to finish. If you slow down for dense chapters, run those parts separately.

Skipped Material

Credits, forewords and appendices count toward the stated length. Skipping them shortens the real listening time. The time calculator subtracts those minutes from the total.

The Narrator

Narrators read at different rates. The same 1.5x setting gives a different number of words per minute for each of them.

This table compares common speeds for a 10 hour book. The last column uses a 150 words per minute narrator, the general speech rate quoted by Murphy, Hoover and Castel (2023).

The saving grows more slowly as speed rises. Going from 1x to 1.5x saves 3 h 20 min. Going from 2.5x to 3x saves only 40 minutes more.

Fitting a Book into a Deadline

A book club meets in two weeks. Enter the length and your daily minutes, then raise the speed until the days to finish drop to 14 or fewer.

Planning a Drive or a Flight

A 6 hour trip and an 8 h 20 min book do not match at 1x. At 1.4x the book runs 5 h 57 min and fits.

Slowing Down on Purpose

Language learners often listen below 1x. The calculator shows the extra time, so a 6 hour book at 0.75x becomes 8 hours.

Comparing Reading with Listening

Pair the result with the reading speed calculator to see whether the print edition would be faster for you.

1. Treating 1.5x as Half the Time

Half the time needs 2x. At 1.5x you save one third, because 1 - 1 / 1.5 = 0.333.

2. Subtracting Instead of Dividing

Taking 25 percent off the length for 1.25x gives the wrong answer. The correct saving at 1.25x is 20 percent.

3. Entering Minutes as a Decimal of an Hour

10 h 30 min is 10.5 hours, not 10.30 hours. Use the two separate fields to avoid the slip, or check a figure with the hours to minutes converter.

4. Dividing an Already Adjusted Time

If your app shows time left at your current speed, dividing it again counts the speed twice.

5. Assuming Faster Always Costs Nothing

Research on lecture videos found the effect depends on the listener. The next section gives the details.

The time arithmetic is exact for one constant speed. The comprehension note is a quoted research figure, not a personal limit.

Murphy, Hoover and Castel (2023) tested lecture videos, not audiobooks. Younger adults watched at faster speeds without significant memory deficits. Older adults generally scored lower at faster speeds. The paper cites a general speech rate of 150 words per minute and older work in which comprehension began to decline at around 275 words per minute. It also notes that people can be trained to follow faster speech.

A 10 hour audiobook at 1.5x takes 6 hours 40 minutes. You divide 600 minutes by 1.5 to get 400 minutes.

A speed of 1.25x saves 20 percent of the listening time. A 10 hour book drops to 8 hours.

At 2x a 10 hour audiobook takes exactly 5 hours, because doubling the speed halves the time.

No. A speed of 1.5x cuts listening time by one third. You need 2x to cut it in half.

Divide the length in minutes by the speed. For 8 h 20 min at 1.6x, 500 / 1.6 = 312.5 minutes, or about 5 h 13 min.

Divide the book length by the listening time you have. A 12 hour book with 8 hours available needs 12 / 8 = 1.5x.

Usually not. Browsers and most apps preserve pitch by default when the playback rate changes, so the voice sounds faster but not higher.

It depends on the narrator. A 150 words per minute reading becomes 300 words per minute at 2x.

It depends on the listener. A 2023 lecture-video study found no significant memory deficit for younger adults at faster speeds, but lower scores for older adults.

No. The calculator runs in your browser and nothing goes to our servers. Saved results stay in this browser only.

• Playback rate: the normal rate is multiplied by the value, and 1.0 is normal speed (MDN Web Docs).
• Pitch is preserved by default when the playback rate changes (MDN Web Docs).
• Digital talking-book players with variable speed controls (National Library Service for the Blind and Print Disabled, Library of Congress).
• The effect of video playback speed on learning and mind-wandering in younger and older adults (Murphy, Hoover and Castel, Memory, 2023; author manuscript on PubMed Central).