Image Size Calculator
Estimate a real JPG/PNG/WebP file size, or the raw uncompressed size, from dimensions.
Calculated locally in your browser.
- Free — no signup, no account, no watermark
- Runs entirely in your browser — nothing is uploaded to a server
- Works on mobile, tablet and desktop
- Instant — results appear as soon as you enter your input
Why this is private
- Calculated locally in your browser.
- Open your browser's DevTools → Network tab while using this tool — you won't see a request carrying your input, because it never leaves your device.
- Nothing you enter is uploaded to a server or shared with us — the processing happens entirely on your device.
Overview
Estimates how big an image file will actually be — pick a format, quality and content type to get a realistic compressed-size range, or switch to the raw calculator for an uncompressed footprint (useful for RAM/VRAM or texture-budget planning).
How to use it
- 1Enter width and height.
- 2For the compressed estimate: pick a format (JPEG, WebP, PNG or GIF), a quality level if the format supports one, and how visually complex the image is.
- 3For the raw estimate: pick a bit depth.
Formula
Raw size
bytes = width × height × (bitDepth / 8)
Compressed estimate
bytes ≈ width × height × bitsPerPixel(format, quality, complexity) / 8
Tips
- The compressed-size figure is an estimate, not a measurement — two photos at the same dimensions, format and quality can differ by 2× or more depending on what's actually in them. Treat the range as a planning number.
- Already have the actual image? Run it through Compress Image to get its real, exact compressed size instead of an estimate.
Frequently asked questions
What people use it for
Will my photos fit an upload or storage limit?Pick your camera or export settings and format to get a realistic per-photo size before you shoot or export a batch.
Estimate the memory an image will useA decoded image sits in RAM at its raw size regardless of how small the file is — useful when a page loads many large photos.
Budget a texture or sprite atlasWork out the uncompressed footprint of game or canvas assets before packing them.
Check a batch will fit a limitMultiply the per-image estimate by the count to see if a set of exports will fit a disk, quota or memory ceiling.
Explain why 'small dimensions' still means a big fileShow a client or teammate the raw pixel cost behind an image before compression.
Related guides
- How to resize a photo and signature for online formsApplication portals want the photo and signature at exact pixel sizes and tiny file sizes. Here's how to hit both without an app.
- How to compress images for the web without them looking badWhy images make pages slow, how much quality you can drop before anyone notices, and a repeatable way to hit a size target.
- How to resize an image without losing qualityWhat 'without losing quality' really means when you resize, why enlarging is different from shrinking, and how to keep proportions intact.
- JPG, PNG or WebP: which image format should you use?A practical guide to picking an image format — what each one is good and bad at, and when to convert.
Related tools
All image toolsImage DPI CalculatorCalculate print size or DPI for a given image — upload it to auto-fill the pixel dimensions.Compress ImageReduce image file size while controlling quality — one image or a whole batch.Resize ImageResize images to exact pixel dimensions or a percentage — one image or a whole batch.Crop ImageCrop an image to a custom or preset aspect ratio.
Ready to use Image Size Calculator?
Image Size Calculator