# Sewing pattern scale calculator

- Human page: https://happytails.ai/en/calculators/sewing-pattern-scale-calculator/
- Markdown: https://happytails.ai/en/calculators/sewing-pattern-scale-calculator.md
- Structured JSON: https://happytails.ai/agents/en/calculators/sewing-pattern-scale-calculator/index.json
- Visibility: public

## Tool capabilities

| Property | Value |
| --- | --- |
| Tool ID | `sewing-pattern-scale-calculator` |
| Category | calculators |
| Implementation | Registered implementation. Registration alone is not a production-quality guarantee. |
| Browser execution | Automatic updates after valid input or file selection. |
| Browser processing | Browser; see tool notes for network behavior. |
| HTTP API | Not callable through HTTP. |
| Browser-agent interface | run_current_tool |

### Implementation notes

Calculate the new absolute print percentage from a measured reference. Print a test with fit-to-page disabled and remeasure before cutting. This does not edit a PDF or grade garment sizes. Changing units keeps the entered numbers. Calculations run on your device.

### Inputs and settings

No free-text input is required. Use the file inputs and/or settings below.

| Setting | Meaning | Control type | Default | Constraints |
| --- | --- | --- | --- | --- |
| `measuredReference` | Reference measured on your current print | number | 9.5 | min=0 max=1000000000 step=any |
| `desiredReference` | Reference size required on the new print | number | 10 | min=0 max=1000000000 step=any |
| `referenceUnit` | Reference measurement unit | select | "cm" | Allowed: mm, cm, m, in, ft, yd |
| `previousScale` | Custom print scale used for the current print (%) | number | 100 | min=1 max=10000 step=any |
| `patternWidth` | Current printed pattern width | number | 20 | min=0 max=1000000000 step=any |
| `patternHeight` | Current printed pattern height | number | 30 | min=0 max=1000000000 step=any |
| `patternUnit` | Pattern dimension unit | select | "cm" | Allowed: mm, cm, m, in, ft, yd |

### Browser-agent workflow

1. Open the human page in a browser that supports WebMCP.
2. Discover the interface exposed by that page; use its actual schema.
3. Select files on the page first when the tool requires files.
4. Call `run_current_tool` with valid input and settings.
5. Inspect the returned result or error and the displayed output. Retrieve files from the displayed download links.

Calls do not automatically copy or download results. Browser permissions still apply. Interface availability alone is not proof of successful execution.

### Planning specification

Recommended print scale from 1% to 10,000%. Produces scale instructions and dimensions, not an edited PDF. Large prints may need tiling.

This describes intended requirements. Use the implementation notes, interface schema and observed output to determine current support.

### Complete machine-readable capability record

```json
{
  "id": "sewing-pattern-scale-calculator",
  "category": "calculators",
  "built": true,
  "requirements": "Recommended print scale from 1% to 10,000%. Produces scale instructions and dimensions, not an edited PDF. Large prints may need tiling.",
  "implementation": {
    "fields": [
      {
        "key": "measuredReference",
        "label": "Reference measured on your current print",
        "value": 9.5,
        "type": "number",
        "min": 0,
        "max": 1000000000,
        "step": "any"
      },
      {
        "key": "desiredReference",
        "label": "Reference size required on the new print",
        "value": 10,
        "type": "number",
        "min": 0,
        "max": 1000000000,
        "step": "any"
      },
      {
        "key": "referenceUnit",
        "label": "Reference measurement unit",
        "value": "cm",
        "type": "select",
        "values": [
          "mm",
          "cm",
          "m",
          "in",
          "ft",
          "yd"
        ]
      },
      {
        "key": "previousScale",
        "label": "Custom print scale used for the current print (%)",
        "value": 100,
        "type": "number",
        "min": 1,
        "max": 10000,
        "step": "any"
      },
      {
        "key": "patternWidth",
        "label": "Current printed pattern width",
        "value": 20,
        "type": "number",
        "min": 0,
        "max": 1000000000,
        "step": "any"
      },
      {
        "key": "patternHeight",
        "label": "Current printed pattern height",
        "value": 30,
        "type": "number",
        "min": 0,
        "max": 1000000000,
        "step": "any"
      },
      {
        "key": "patternUnit",
        "label": "Pattern dimension unit",
        "value": "cm",
        "type": "select",
        "values": [
          "mm",
          "cm",
          "m",
          "in",
          "ft",
          "yd"
        ]
      }
    ],
    "input": false,
    "live": true,
    "background": false,
    "presentation": "metrics",
    "note": "Calculate the new absolute print percentage from a measured reference. Print a test with fit-to-page disabled and remeasure before cutting. This does not edit a PDF or grade garment sizes. Changing units keeps the entered numbers. Calculations run on your device.",
    "experience": {
      "automatic": true,
      "single": false,
      "inputMaxLength": 1000000,
      "inputMode": "text",
      "label": "Your text",
      "placeholder": "Type or paste your input…",
      "help": "Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.",
      "action": null
    },
    "mode": "automatic",
    "interactive": false
  },
  "execution": "Browser interface",
  "api": null,
  "browser_agent": {
    "supported": true,
    "name": "run_current_tool",
    "discovery": "WebMCP on the human page in a supporting browser",
    "verification": "See audit/API-AUDIT.md; availability is not verification"
  }
}
```

## Page guide

Calculate a print percentage from a measured reference and see the expected uniformly scaled pattern dimensions.

How can we improve this tool?

Report a problem or share an idea.

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### How to use Sewing pattern scale calculator

1. Enter your measurements, rates or supplied recipe.
2. Review the quantities, rounding and plan details.
3. Download the result and verify it against your actual materials or a sample.

## Useful next steps

- [Origami paper size calculator](https://happytails.ai/en/calculators/origami-paper-size-calculator/) ([Markdown](https://happytails.ai/en/calculators/origami-paper-size-calculator.md))

- [Fabric shrinkage calculator](https://happytails.ai/en/calculators/fabric-shrinkage-calculator/) ([Markdown](https://happytails.ai/en/calculators/fabric-shrinkage-calculator.md))

## Measure the print you actually have

Enter a reference length measured on the current printed pattern and the intended new reference length. Also enter the custom scale used to produce that print. This accounts for an earlier print that was already enlarged or reduced.

### Verify the new reference before cutting

A reference printed as 9.5 cm instead of 10 cm at 100% calls for approximately 105.263% custom scale. Disable automatic fit-to-page and measure the new print in both directions. Uniform scaling also changes seam allowances and does not replace garment grading.

### Save the plan

Download the result as CSV, plus a text or JSON report with formulas, values and assumptions. Everything is calculated on your device. Changing units keeps the entered numbers, so check the selected units before using the plan.