# Photo Print Size Planner

> Find how large your photo can print at your chosen resolution. Convert image pixel dimensions into print dimensions in inches and centimeters at a specified pixels-per-inch resolution. Compare sizes without uploading the image.

Part of usefulweb.site (https://usefulweb.site/). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://luminaprintplanner.usefulweb.site/ (interactive tool at https://luminaprintplanner.usefulweb.site/tool)
- JSON API: POST https://luminaprintplanner.usefulweb.site/api/v1/calculate with a JSON object of inputs (schema: https://luminaprintplanner.usefulweb.site/api/v1/tool)
- OpenAPI: https://luminaprintplanner.usefulweb.site/openapi.json
- MCP (Streamable HTTP): https://luminaprintplanner.usefulweb.site/mcp - tool `lumina_print_planner`

## Inputs
- width (integer): Photo width (px)
- height (integer): Photo height (px)
- ppi (integer): Print resolution (PPI)

## Method
- Print width in inches equals pixel width divided by PPI. One inch equals 2.54 centimeters.
- PPI describes image pixel density, not printer dot density. Calculated dimensions do not guarantee print quality.