# CSS Design Calc – Pixel Density Calculator

> CSS Design Calc – Pixel Density Calculator is a paid API for AI agents from css-design-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Computes screen PPI, physical dimensions, CSS viewport size, dot pitch, and image widths for a given screen resolution and diagonal.

## Facts

- Endpoint: GET https://css-design-calc.x402tookit.com/pixel-density?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/css-design-calc-pixel-density-calculator-28e74866
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_3inUhA5wE1DJVx5XhjAGC

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability css-design-calc-pixel-density-calculator-28e74866
```

Example prompt: What's the pixel density and CSS viewport size for a 2560×1440 screen with a 27-inch diagonal and a device pixel ratio of 2? Also tell me the image widths I'd need for a 300px CSS width.

## When to prefer this

Use this endpoint when you need precise, multi-faceted screen metric calculations — PPI, physical dimensions, CSS viewport, dot pitch, and responsive image widths — all in a single call. Prefer it over manual calculations or general-purpose math tools when working with CSS/responsive design workflows, evaluating display quality, or planning srcset breakpoints.

## Known failure modes

- Missing required query params (widthPx, heightPx, diagonalIn) returns an error
- Non-positive or physically impossible values (e.g. diagonalIn=0) may return null fields or an error
- Very unusual DPR values may result in degraded or partially null output
- Network timeout if the service is temporarily unavailable

## How this service works

Screen pixel density (PPI) from resolution and diagonal, physical size, CSS viewport at a device pixel ratio, and image widths.

## Output

Returns a structured object with PPI value and PPI class (e.g. retina, standard), physical width and height in mm and inches, dot pitch in mm, megapixel count, CSS viewport width and height at the given DPR, CSS pixel size in mm, and image pixel widths for 1x/1.5x/2x/3x DPR at the specified CSS width, plus a human-readable summary and verdict.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "widthPx",
      "heightPx",
      "diagonalIn"
     ],
     "properties": {
      "dpr": {
       "type": "number",
       "description": "Device pixel ratio the browser reports (default 1)"
      },
      "widthPx": {
       "type": "number",
       "description": "Horizontal resolution in physical pixels"
      },
      "cssWidth": {
       "type": "number",
       "description": "A CSS width in px to compute image pixel widths for (default 100)"
      },
      "heightPx": {
       "type": "number",
       "description": "Vertical resolution in physical pixels"
      },
      "diagonalIn": {
       "type": "number",
       "description": "Screen diagonal in inches"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "dpr": {
       "type": [
        "null",
        "number"
       ]
      },
      "ppi": {
       "type": [
        "null",
        "number"
       ]
      },
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "widthMm": {
       "type": [
        "null",
        "number"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "heightMm": {
       "type": [
        "null",
        "number"
       ]
      },
      "ppiClass": {
       "type": [
        "null",
        "string"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "dotPitchMm": {
       "typ
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/css-design-calc-pixel-density-calculator-28e74866/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from css-design-calc.x402tookit.com](https://www.zero.xyz/host/css-design-calc.x402tookit.com/llms.txt)