Mass convert

mass-convert · version 1.0.0 · Units & sizes · free, no key needed

Convert a canonical integer mass amount between exact nanogram-based units as a reduced rational.

Use when you need to: mass convert · convert mass units · convert grams kilograms pounds.

Supported

• mass convert
• convert mass units
• convert grams kilograms pounds

Not supported

• troy ounces or pounds
• stone
• short tons
• long tons
• floating-point mass
• SI prefixes other than ng ug mg g kg t

Behavior

• value is a canonical integer string amount in the from unit; negative amounts are allowed and -0 canonicalizes to 0.
• Units are exactly ng, ug, mg, g, kg, t, oz, and lb from MASS_NG.
• t is the metric tonne (1000 kg); lb is the international avoirdupois pound (exactly 0.45359237 kg); oz is 1/16 lb.
• Conversion is the exact rational value * from_ng / to_ng, reduced by gcd, with the sign only on the numerator.
• The output is a canonical rational {numerator, denominator} expressed in the to unit.
• Unknown units, unknown fields, non-canonical integers, and results whose reduced components exceed 1000 digits are rejected.

Input

• value (string, required): max length 1001; pattern ^-?(0|[1-9][0-9]*)$
• from (one of "ng", "ug", "mg", "g", "kg", "t", "oz", "lb", required)
• to (one of "ng", "ug", "mg", "g", "kg", "t", "oz", "lb", required)

Output

• numerator (string, required): pattern ^(0|-?[1-9][0-9]*)$
• denominator (string, required): pattern ^[1-9][0-9]*$

Limits

• max digits: 1000

Example

Request input:

{
  "value": "500",
  "from": "mg",
  "to": "g"
}

Response:

{
  "result": {
    "numerator": "1",
    "denominator": "2"
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "mass-convert",
  "version": "1.0.0",
  "input": {
    "value": "500",
    "from": "mg",
    "to": "g"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/mass-convert/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"value":"500","from":"mg","to":"g"}'

The machine-readable contract is at /v1/tools/mass-convert/versions/1.0.0.

CLI

node cli.mjs run mass-convert 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

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