vision-coordinates changedbuild-with-claude/vision-coordinates
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99You'll need this for OCR pipelines, form extraction, chart parsing, UI element location, and any task where you act on a specific region of an image. For sending images, supported formats, and per-model resolution limits, see [Vision](https://platform.claude.com/docs/en/build-with-claude/vision).
1010
1111<Note>
12 **Claude works best with absolute pixel coordinates.** Ask for them explicitly in your prompt. For example: *"Return the bounding box of each table as `[x1, y1, x2, y2]` (top-left and bottom-right corners) in pixel coordinates."* Claude does not work well when you ask for normalized coordinates, for example: *"Return bounding box coordinates between `0` and `1000`."* Always ask for pixel coordinates and normalize in your own code if you need to. To get coordinates as machine-readable JSON instead of prose, define a schema with [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs), for example an object with an `[x1, y1, x2, y2]` array per detected element.
12 **Claude works best with absolute pixel coordinates.** Ask for them explicitly in your prompt. For example: *"Return the bounding box of each table as `[x1, y1, x2, y2]` (top-left and bottom-right corners) in pixel coordinates."* Claude does not work well when you ask for normalized coordinates, for example: *"Return bounding box coordinates between `0` and `1000`."* Always ask for pixel coordinates and normalize in your own code if you need to. To get coordinates as machine-readable JSON instead of prose, define a schema with [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs), for example an object with an `[x1, y1, x2, y2]` array for each detected element.
1313</Note>
1414
15Coordinates follow the standard image convention: the origin `(0, 0)` is the top-left corner of the image, with x increasing to the right and y increasing downward. The coordinates Claude returns are pixel positions in the image Claude sees: your image after Claude resizes it to fit the model's native resolution (see [How Claude resizes and pads images](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#how-claude-resizes-and-pads-images)). To get coordinates you can use directly, either pre-resize your image so the coordinates map one-to-one onto the image you have (see [Resize your image before uploading](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#resize-your-image-before-uploading)), or rescale the coordinates Claude returns (see [Rescale coordinates when you cannot pre-resize](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#rescale-coordinates-when-you-cannot-pre-resize)).
15Coordinates follow the standard image convention: the origin `(0, 0)` is the top-left corner of the image, with x increasing to the right and y increasing downward. The coordinates Claude returns are pixel positions in the image Claude processes: your image after Claude resizes it to fit the model's native resolution (see [How Claude resizes and pads images](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#how-claude-resizes-and-pads-images)). To get coordinates you can use directly, either pre-resize your image so the coordinates map one-to-one onto the image you have (see [Resize your image before uploading](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#resize-your-image-before-uploading)), or rescale the coordinates Claude returns (see [Rescale coordinates when you cannot pre-resize](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#rescale-coordinates-when-you-cannot-pre-resize)).
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1717<Note>
1818 Claude's spatial reasoning has limits (see [Limitations](https://platform.claude.com/docs/en/build-with-claude/vision#limitations)). Coordinate accuracy is best when you state the expected coordinate format in your prompt and spot-check results visually before processing at scale. Small elements lose precision when an image is downscaled: for fine targets, crop the region of interest and send the crop (offset returned coordinates by the crop origin), or use a high-resolution-tier model. For [PDF support](https://platform.claude.com/docs/en/build-with-claude/pdf-support), pages are rasterized to images server-side at dimensions you don't control, so the returned coordinates can't be reliably mapped back onto the page. To work with coordinates on PDF content, rasterize the pages to images yourself and use the pre-resize approach.
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3939
4040## Resize your image before uploading
4141
42The most reliable approach is to resize your image yourself before uploading, so the image you have is exactly the image Claude sees and the coordinates Claude returns need no conversion.
42The most reliable approach is to resize your image yourself before uploading, so the image you have is exactly the image Claude processes and the coordinates Claude returns need no conversion.
4343
4444First check which resolution tier your model is on (see [Resolution and token cost](https://platform.claude.com/docs/en/build-with-claude/vision#evaluate-image-size)) and pass the matching edge and token limits. The following reference implementation computes the exact size Claude resizes an image to:
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457457}
458458```
459459
460A request whose marked image (any block that sets `"oversized_image": "error"`) would be resized is rejected with a 400 `invalid_request_error` naming the image's dimensions and the largest dimensions that fit. Whether an image triggers the rejection depends on the [limits of every model the request names](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#how-claude-resizes-and-pads-images): the 1920×1080 example below is rejected by a standard-tier model but fits within the high-resolution tier:
460A request whose marked image (any block that sets `"oversized_image": "error"`) would be resized is rejected with a 400 `invalid_request_error` naming the image's dimensions and the largest dimensions that fit. Whether an image triggers the rejection depends on the [limits of every model the request names](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#how-claude-resizes-and-pads-images): the following 1920×1080 example is rejected by a standard-tier model but fits within the high-resolution tier:
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462462```text wrap
463463messages.0.content.0: image dimensions 1920x1080 exceed the maximum image size of a model named on this request and would be downsized to 1456x819; scale the image to at most 1456x819 or set the image's oversized_image setting to "downsize"
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466466Rescale to the reported target and resend: the target is the largest size, at your image's aspect ratio, that every model named on the request accepts. How marked images interact with the [server-side fallback beta](https://platform.claude.com/docs/en/build-with-claude/refusals-and-fallback#server-side-fallback) is described with that feature; in every mode, a marked image is never served resized.
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468The setting is per image. `"oversized_image": "downsize"` (the default when the field is omitted) keeps automatic resizing as described on this page. Each image block is checked only against its own setting, so one request can mix images whose dimensions are load-bearing (a screenshot you'll click on) with images where resizing is harmless (a logo). What the setting does and does not change:
468Each image has its own setting. `"oversized_image": "downsize"` (the default when the field is omitted) keeps automatic resizing as described on this page. Each image block is checked only against its own setting, so one request can mix images whose dimensions matter (a screenshot you'll click) with images where resizing is harmless (a logo). What the setting does and does not change:
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470* Padding ([which never discards content](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#how-claude-resizes-and-pads-images)), format conversion, and orientation correction proceed as usual.
470* [Padding](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#how-claude-resizes-and-pads-images) (which never discards content), format conversion, and orientation correction proceed as usual.
471471* The hard limits (8000 px on the longest side, and the stricter per-image limit on [many-image requests](https://platform.claude.com/docs/en/build-with-claude/vision#request-limits)) are separate rejections; this setting never lets an image past them.
472472* Images supplied by URL or file ID are checked once their bytes have been fetched; those rejections carry the same message without the leading position, so they don't identify which image failed; only embedded base64 images are named by position in the error.
473473* [PDF pages](https://platform.claude.com/docs/en/build-with-claude/pdf-support) are rasterized server-side at dimensions you don't control; the `document` block does not accept the field (an image block nested inside a document's content accepts it like any other).
474* A marked image whose dimensions cannot be determined is rejected rather than passed through: that rejection reports that the image's source dimensions could not be determined, not the resize message quoted above. No image that sets `"error"` reaches the model resized.
474* A marked image whose dimensions cannot be determined is rejected rather than passed through: that rejection reports that the image's source dimensions could not be determined, not the resize message quoted earlier. No image that sets `"error"` reaches the model resized.
475475
476476The [Token counting](https://platform.claude.com/docs/en/build-with-claude/token-counting) endpoint honors `transformations` too, rejecting an embedded image exactly as the Messages API would, so you can check whether an embedded image fits without being resized, before running inference. Counting rejects images supplied by URL or file ID rather than fetching them, so a marked image from those sources is checked only at Messages time.
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478478## Rescale coordinates when you cannot pre-resize
479479
480If you cannot pre-resize (for example, when the image comes from an upstream system you can't modify), use the resize helper from [Resize your image before uploading](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#resize-your-image-before-uploading) to recover the dimensions Claude saw, then map the coordinates Claude returns into normalized coordinates or back onto your original image. Unless an image [opts into an error instead](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#oversized-image-error), Claude resizes oversized images rather than rejecting them, up to the API's [request limits](https://platform.claude.com/docs/en/build-with-claude/vision#request-limits). Beyond those limits the request fails with a validation error instead. Pass the tier limits that match the model you called: the wrong tier's limits recover the wrong resized dimensions and silently shift every coordinate. This approach requires knowing the pixel dimensions of the image you uploaded, so it does not apply to PDF uploads.
480If you cannot pre-resize (for example, when the image comes from an upstream system you can't modify), use the resize helper from [Resize your image before uploading](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#resize-your-image-before-uploading) to recover the dimensions of the image Claude processed, then map the coordinates Claude returns into normalized coordinates or back onto your original image. Unless an image opts into an [oversized-image error](https://platform.claude.com/docs/en/build-with-claude/vision-coordinates#oversized-image-error) instead, Claude resizes oversized images rather than rejecting them, up to the API's [request limits](https://platform.claude.com/docs/en/build-with-claude/vision#request-limits). Beyond those limits the request fails with a validation error instead. Pass the tier limits that match the model you called: the wrong tier's limits recover the wrong resized dimensions and silently shift every coordinate. This approach requires knowing the pixel dimensions of the image you uploaded, so it does not apply to PDF uploads.
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482482Screenshots and zoom images that you return to the [computer use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/computer-use-tool#handle-coordinate-scaling-for-higher-resolutions) and [browser use](https://platform.claude.com/docs/en/agents-and-tools/tool-use/browser-use-tool#targets-and-coordinates) toolsets are an exception to automatic resizing. The API rejects a `tool_result` image that exceeds the model's limits with a validation error instead of resizing it. Resize those images in your application before returning them, then scale the coordinates Claude returns back to your screen's dimensions.
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