Get exact encoded canvas dimensions without uploading the file or relying on a filename, CMS preview, or CSS display size. The parser handles extended VP8X, classic lossy VP8, and lossless VP8L headers and distinguishes an animation canvas from frame rectangles.
How to use WebP Dimensions Checker
- Add WebP images whose intrinsic pixel dimensions you need to verify.
- Run the checker to read the appropriate WebP header and calculate width, height, aspect ratio, and megapixels.
- Compare intrinsic dimensions with the intended display slot, then use the WebP Resizer separately if physical pixels need to change.
What this tool is good at
When to use WebP Dimensions Checker
Make a precise dimension decision
Verify intrinsic pixels for responsive slots, CMS limits, memory estimates, or unexpected layout softness. The result is based on the selected file's actual bytes or decoded frames, so it can support a concrete publishing or engineering decision instead of a filename-based assumption.
Troubleshoot a private production asset
Use the browser-local workflow for client images, unreleased campaigns, product media, or internal fixtures when sending the source to a generic third-party utility would create unnecessary exposure.
Document repeatable asset checks
Keep the generated output or JSON report with a ticket, content review, or migration record. Compare intrinsic width and height with the largest real display requirement before deciding whether to resize or keep additional density. This makes the finding reproducible for another editor or developer.
How to choose the right settings
Start from the intended destination
Compare intrinsic width and height with the largest real display requirement before deciding whether to resize or keep additional density. Choose settings or interpret results in the context of the actual CMS, browser, editor, size budget, animation player, or privacy policy that will consume the WebP.
Separate container facts from visual judgment
RIFF chunks, dimensions, alpha values, and encoded bytes answer technical questions, while perceived sharpness, acceptable motion, and brand appearance still require a human preview at the real display size.
Retain the authoritative original
Intrinsic pixels are not CSS size, device-pixel density, print DPI, or proof that the asset is visually sharp. Keep the source until the derivative or report has been reviewed, downloaded, and tested in the destination workflow.
Practical workflow and output details
VP8X, VP8, and VP8L headers are parsed directly and aspect ratio plus megapixels are calculated without relying on EXIF. File bytes remain in the current browser tab; only static application code or codec assets are fetched, and no image-processing request is sent to PicConverters.
Intrinsic pixels are not CSS size, device-pixel density, print DPI, or proof that the asset is visually sharp. The tool reports or changes only the scope named on the page and avoids implying broader repair, anonymity, visual quality, or cross-application compatibility than the operation can establish.
Format behavior and limitations
Intrinsic pixels are different from CSS display dimensions, density metadata, print DPI, or the dimensions at which a browser may render a responsive layout.
For animation, the main width and height describe the canvas. Individual ANMF rectangles can be smaller and are available in the File Analyzer report.
Frequently asked questions
Does this use EXIF dimensions?
No. It reads WebP image headers, which define the actual encoded canvas. EXIF dimension tags can be absent or stale.
Why does a website display the image at another size?
HTML, CSS, responsive layout, and device pixel ratio can scale intrinsic pixels. This report describes the file itself.
Can the checker resize the WebP?
No. It is read-only. Use WebP Resizer after confirming the dimensions you have and the dimensions you need.
Related WebP tools
Resize WebP
Resize static WebP images to a precise width while keeping the original aspect ratio.
WebP File Analyzer
Create a detailed local report covering WebP encoding, dimensions, chunks, payload bytes, overhead, animation, alpha, and metadata.
WebP Validator
Validate RIFF bounds, image payloads, animation structure, dimensions, and feature-flag consistency without altering the file.