Audiobook length calculator
This audiobook length calculator turns your word count into finished hours, shows the studio hours behind them and, if you want it, what narration costs and how many sales pay it back. An 80,000-word book at 155 words a minute runs about 8.6 finished hours (8 hours 36 minutes), which is why ACX's rule of thumb is 9,300 words an hour. Listening instead? The playback figures below answer "how long at 1.5x."
Want the real number for your book? Get a fixed audiobook quote from the studio.
How to use the audiobook length calculator
Heavy dialogue and technical text both run longer.
For a per-hour deal, type the rate you were quoted.
How the audiobook length calculator works
Finished hours are words, divided by pace, divided by 60, times a material factor. At 155 words a minute that's 9,300 words an hour, the figure ACX gives: "most performers narrate about 9,300 words per hour," per ACX's guide to producing and recording an audiobook. So 80,000 / 155 / 60 = 8.60 hours. Heavy dialogue multiplies by 1.06 and technical material by 1.12, our own assumptions, not ACX numbers.
Studio hours are finished hours times 6.2, ACX's estimate of about 2 hours recording, 3 editing and 1.2 review for each finished hour. The default book comes to 53 hours 20 minutes.
Cost for a per-hour deal is finished hours times your rate, plus about $60 an hour if proofing and mastering are billed separately. Per sale is the retail price times your royalty percentage, an estimate only, since ACX's own payout rules decide the real figure. Break even is cost divided by per sale, rounded up. Royalty share and narrating it yourself carry no cash cost, so break even reads "None to make back."
Cost for a per-hour deal is finished hours times your rate, plus about $60 an hour if proofing and mastering are billed separately.
Worked examples
Every figure below comes from running the tool's own formulas: $260 an hour, $19.99 retail, 50 percent exclusive royalty, 155 words a minute unless stated.
| Book | Finished | Studio | Cost | Break even |
|---|---|---|---|---|
| 80,000-word book, straight narrative (the default) | 8h 36m | 53h 20m | $2,236.56 | 224 sales |
| 60,000-word memoir | 6h 27m | 40h 00m | $1,677.42 | 168 sales |
| 45,000-word business book | 4h 50m | 30h 00m | $1,258.06 | 126 sales |
| Same book marked technical (x1.12) | 5h 25m | 33h 36m | $1,409.03 | 141 sales |
| 120,000-word fantasy, many voices (x1.06) | 13h 41m | 84h 48m | $3,556.13 | 356 sales |
Pace alone moves the bill: the default book at 140 words a minute costs $2,476.19, and at 170 it costs $2,039.22, a $437 gap. Proofing and mastering billed at $60 an hour adds $516.13 ($2,752.69), so ask whether a quote includes it.
Royalty choices change the payback. At the default 50 percent a sale is $9.99 (50 percent of $19.99 is $9.995). Non-exclusive 30 percent gives $6.00 and a break even of 373 sales. A royalty share costs nothing up front but, on our 50/50 assumption, pays you $5.00 a sale.
What the numbers mean
Narrators and studios quote on finished hours, so the runtime is the number to compare quotes against. Narrating it yourself means about 53 studio hours, roughly 6.7 full eight-hour working days.
For listeners, divide the runtime by the playback speed. The default 8h 36m book plays in 6h 53m at 1.25x, 5h 44m at 1.5x, 4h 55m at 1.75x and 4h 18m at 2x. Reading is faster: at the 238 words a minute our word count tool uses, 80,000 words takes 5h 36m.
ACX takes MP3 at 192 kbps or higher, about 86.4 MB an hour (192,000 / 8 x 3,600), so roughly 743 MB for 8.6 hours. Each file can run 120 minutes at most. See the full ACX audio submission requirements. Break even counts money only.
ACX takes MP3 at 192 kbps or higher, about 86.4 MB an hour (192,000 / 8 x 3,600), so roughly 743 MB for 8.6 hours.
Common mistakes with audiobook estimates
Mixing finished and studio hours
Listings show finished hours. The studio time is the work behind them.
Counting pages
Pages vary with trim size, so work from words.
Estimating before the text is final
Corrections after recording mean paid pickups.
Treating a rate as the price
Ask whether mastering and proofing are in it.
Using old royalty terms
The rates changed in 2026. See the FAQ.
Tips by situation
Nonfiction and business books
Expect the technical factor. Give your narrator a pronunciation list before recording.
Fiction with many characters
Dialogue lengthens the book. Audition narrators on a dialogue passage, not just the opening paragraph.
A backlist book with sales history
A royalty share can make sense when the book already sells. A debut rarely earns enough to split with a narrator.
Related guides from the Author Resources hub
Publishing costs
Royalties
ISBNs
From an estimate to a fixed quote
This page estimates. A quote comes from reading your book. Our audiobook production starts from $260 per finished hour and covers narrator casting, direction, mastering to retailer specification and delivery to ACX (see our published rate). We read a sample first, then give you a fixed quote.
Questions we get asked
How long is an audiobook for a 350 page book?
About 9h 25m to 11h 17m. At 250 to 300 words a page, 350 pages is 87,500 to 105,000 words, which is 9.4 to 11.3 hours at 155 words a minute. Trim size changes words per page, so use your real word count when you have it.
How many words make an hour of audiobook?
About 9,300. ACX says most performers narrate that many words an hour, which is 155 a minute. Divide your word count by 9,300 for finished hours: 80,000 words is 8.6.
How long is a 6 hour audiobook at 1.5x?
Four hours. Divide the length by the speed.
Is it quicker to read or listen?
Reading, usually: 80,000 words takes 5h 36m at 238 words a minute, against 8h 36m to hear.
How do I work out the audio file size?
Multiply bitrate by time. At 192 kbps, 192,000 / 8 x 3,600 gives 86.4 MB an hour, so 8.6 hours is about 743 MB.
How long does it take to record an audiobook?
ACX estimates about 6.2 hours of work per finished hour: roughly 2 recording, 3 editing and 1.2 review. An 8.6-hour book is therefore around 53 hours of studio work.
How much does it cost to produce an audiobook?
It depends on finished hours and the rate. Ours starts from $260 per finished hour (see pricing), so 8.6 hours starts around $2,240. Ask what any quote includes. For a quote on your book, see our audiobook production services.
What royalty do authors earn on ACX?
As of October 2026, ACX lists 50 percent for exclusive and 30 percent for non-exclusive under its new terms, which cover books claimed from May 26, 2026. The legacy rates are 40 and 25 percent. Check ACX before relying on any figure.
Keep going with the next tool
Try the royalty calculator, the budget and break-even calculator or browse all author tools.
Tools will only take you so far
Send what you have. Even a half-written manuscript is enough for a reader to tell you what it needs.