How To Reduce The File Size Of An Ebook Manuscript

How To Reduce The File Size Of An Ebook

Why should you check the file size of an ebook? Because it can cost you money.

The bigger your ebook file size is, the more Amazon KDP charges you to deliver your Kindle ebook.

It hardly seems fair because most other self-publishing services don’t charge you for the delivery of an ebook.

But if you publish on Amazon, the charges can mount up quickly.

How much does Amazon charge for ebook delivery?

If you choose the 35% royalty option with KDP, there is no delivery charge.

But very few authors choose this option. Logically, most will choose the 70% royalty option.

However, you are then subject to Amazon’s delivery charge of $0.15 per megabyte.

It might not sound like a lot of money, but an ebook selling at $2.99 will give you a net royalty of $2.09.

Even if your ebook is only one megabyte, your net royalty reduces to $1.94.

But if the file size of an ebook is five megabytes, the net royalty reduces to $1.19.

You can see why it is well worth checking the size of your publishing files before you upload your ebook.

But if you have already published, it’s not too late. Go to your book on Amazon, and the file size of your book is listed under Product Details. It’s in kilobytes, so 1,000 KB equals one megabyte.

You can always modify or compress your original files and upload and republish the new version on KDP.

Now you know why size is critical, let’s look at ways to reduce the size and make a better return on your ebook sales.


Check your word processor file

The best place to start is at the beginning. A word processor file of your manuscript is easy to check.

Locate your file and check the Properties on a PC, or Get Info on a Mac.

Depending on your computer, you might also see the file size in a preview pane.

Either way, check the file size to see if your problems are within your original manuscript file.

Here are two examples.

Ebook file size 2

That’s about right for a clean Word file of around 40,000 words.

But it’s not always the case.

Ebook file size

This file can potentially lose about $0.45 per sale for delivery changes, so it needs some work.

The first step is to check if your word processor has an option to reduce the size of a file.

Reduce file size option

If so, give it a try. In most cases, it will help a little.

However, if your file size is still two or three megabytes, you’ll need to take a closer look to find what is bloating the file.


Images are notorious for eating your royalty

If your ebook is only text, you can almost always keep the size to around or under one megabyte.

But always check your book cover file.

Amazon KDP recommends a maximum size of 2560 x 1600 pixels and a resolution of 72 dpi. Although Amazon will compress the file, it’s best to optimize your file before uploading.

But if you include images in your ebook, watch out. Without taking care to resize and optimize images, you could be losing a lot of money.

Here are a few ideas to help you reduce your image sizes.

1. Use JPEG for photos and images and PNG for graphics. Never use BMP files because they are uncompressed and huge.

2. Resize your images to a maximum of 700 px wide, and less if possible.

3. The resolution should be 72 dpi for all ebook images.

4. Use an online image compressor. You can check our tutorial on how to compress images.

Here’s an example of how much you can save.

A book cover from my designer was 4800 x 2800px, 300 dpi, and over 5MB. It was perfect for a print book but way too big for an ebook.

But by resizing it to 1400  ×  2100px and reducing the resolution to 72 dpi, the file is only 311KB.

That’s how much you can save by paying close attention to your image sizes and resolution.


Use Calibre to help you with epub files

Calibre is a free tool every ebook author should have.

But one helpful feature is compressing images in epub files.

All you need to do is right-click on your book and select edit.

Calibre Edit Book

When it opens, go to the Tools menu and select Compress images losslessly.

Calibre Compress

You will then see a list of all the images in your ebook. Select the percentage option on the right to compress all of your images.

Caibre Compress options

If you want to experiment with the percentage options, make a copy of your ebook. Then, you can compare the results.


Other causes of large ebook files

Code bloat is often an issue in word processors, and perhaps Word in particular.

Because it takes a long time to write a book, all the changes, opening and closing, copying and pasting, revisions, and track changes can all add background code.

The best practice is to copy all the text, and then paste it into a plain text editor, and save it as plain text.

Then, copy the plain text and paste it into a new word processor file.

Yes, you will lose all your formatting, so you will have to apply it all again. But it’s worth the effort because your file size should be much smaller.

The other benefit is that it will also clean any background code that may cause errors when you come to publish your manuscript.

One other tip is to stick with standard fonts like Arial or Times New Roman because they are smaller and universally supported.



Every byte and every penny counts on Amazon KDP.

Check your manuscript size, and if you have images, make sure they are as small as possible.

Better still, if some images are unnecessary or purely decorative, consider deleting them from your ebook.

Remember, you will lose $0.15 per megabyte on every ebook you sell on the Kindle Store.

If you sell 1,000 ebooks with a file size of 4 megabytes, you will lose around $600.00 in delivery charges.

But when you reduce the file size to just under one megabyte, you will only pay $150.00 in charges.

That adds up to 450 excellent reasons to check and reduce the file size of an ebook.


Related Reading: How To Download Your Kindle Ebook From Amazon KDP

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