Image Crop Size Calculator

Image Crop Size Calculator helps you calculate largest crop dimensions for image crop from the values you already have. Enter Source Width, Source Height, and Target Aspect Ratio, and the calculator uses those values to show largest crop dimensions. It helps with image crop when digital values use different units or need to be translated into a more practical figure. Real devices, networks and software can add limits or overhead that are not represented by a simple numerical input. Before acting on an important result, review the inputs once more so the largest crop dimensions reflects the situation you actually want to plan. Read the worked example on the Image Crop Size Calculator page if you want to check how the entered values lead to largest crop dimensions before using your own figures.

How to use Image Crop Size Calculator

To use Image Crop Size Calculator, start with the values that apply to your image crop case. Enter the whole-number value for Source Width, then enter the whole-number value for Source Height and Type the required text into Target Aspect Ratio. Run the calculation to see largest crop dimensions, then compare the answer with the values you entered before using it. Keep proportional resizing enabled when you want to preserve the original aspect ratio rather than stretch the result. Before relying on an important answer, review the entered values once more so largest crop dimensions reflects the situation you actually want to calculate. The worked example on the Image Crop Size Calculator page can help you confirm how the inputs should be entered before you calculate your own case. Use the actual source values where possible rather than rounded guesses, especially when a small input change could noticeably affect largest crop dimensions.

Why use this tool?

Use Image Crop Size Calculator when image crop requires a small digital calculation that would otherwise mean converting several units by hand. It gives you a consistent result for comparing files, screens, images, text or transfer settings. Because the calculation is based on Source Width, Source Height, and Target Aspect Ratio, you can see which values need to change when you want to test another case. Because Image Crop Size Calculator focuses only on image crop, you can change one input at a time and see how that affects largest crop dimensions without changing the basis of the comparison. This also makes Image Crop Size Calculator practical for checking more than one image crop option, because each run uses the same calculation and the same input definitions.

How the calculation works

Image Crop Size Calculator calculates the largest centred rectangle with the target aspect ratio that fits inside the source image. The result is worked out from Source Width, Source Height, and Target Aspect Ratio, with each field applied according to the rule above. When proportional resizing is used, the original aspect ratio is preserved so the image or shape is not stretched; cropping is a separate choice. The result is reported as largest crop dimensions from the text supplied, so editing the source text and running the tool again updates the output. When comparing two text versions, use the complete text in both cases and keep the same formatting and counting rules.

Example

For example, enter Source Width = 10, Source Height = 5, and Target Aspect Ratio = 3:4. The calculated result is 3 × 5 px. This works by calculating the largest centred rectangle with the target aspect ratio that fits inside the source image, which gives the displayed largest crop dimensions.

Practical tip

For Image Crop Size Calculator, use the complete, final content for Source Width, Source Height, and Target Aspect Ratio rather than a shortened sample when the exact text affects the answer. Keep the same units and assumptions whenever you compare two results from this tool. If largest crop dimensions is being used for export or upload planning, test the final file or settings as well as relying on the estimate. For a second image crop case, keep the same units and conventions and change only the values that genuinely differ.