Free Calculator for Image Sizes

How To Calculate Image Size

Image sizing is crucial for authors to ensure their books are printed with a professional finish. By tailoring images to fit the specific dimensions of your book, you’ll avoid having your images stretched, distorted, or pixelated.

Considering factors like trim, bleed, and margins helps to create a seamless layout where images and text complement one another. Properly adjusted trim ensures images don’t get cut off, while accounting for bleed guarantees that images extend to the very edge of the page. Mindful margins prevent important visual elements from being lost or obscured in the binding.

Overall, precise image sizing creates a polished, visually pleasing book that you will be proud of and your readers will rave about.

If you print with KDP, Amazon requires all full bleed PDFs to extend 0.125” beyond the chosen trim size of a book on the top, bottom and outer edge.

To calculate the bleed required for your chosen trim size, use this formula:

• Single Page Width in Inches: Trim Size Width + 0.125″
• Height in Inches: Trim Size Height + 0.25″
• Pixels = inches x ppi

What is PPI?

PPI is pixels per inch. You may also see this referred to as DPI, or dots per inch. For a high resolution image, use 300 ppi

Here is a handy calculator to help.

Calculate Bleed for a Full Page Image

To use the calculator, enter the trim size you will print your book and press Calculate.

Individual Chapter Images

If you are adding an image within a chapter, it will not extend to the very edges of the page, but will rather fit within the margins, similar to your text. To size this properly, you will need to know the trim size of your book and the margins you’ll be using.

To calculate the image size required fit within the margins of your chosen trim size, use this formula:

• Single Page Width in Inches: Trim Size Width – (Inside Margin + Outside Margin)
• Pixels = inches x ppi

NOTE: The length of your image will depend on the layout of the image you’re creating, but you should always create it to suit the maximum width calculated to fit within the margins.

Calculate Image to Fit Within Margins

To use this calculator, enter the width of the trim size of your book, and the inside and outside margins. The default margins as suggested by Atticus are set, but you can adjust if your book uses custom margins.