Number engineering format

number-engineering-format · version 1.0.0 · Numbers & math · free, no key needed

Format an exact decimal in scientific or engineering notation with explicit precision and rounding.

Use when you need to: format an exact decimal in engineering notation · format a number in scientific notation · round a decimal to significant digits for engineering display.

Decide before calling

Read the versioned contract and the supported scope below. Reuse number-engineering-format@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use number-engineering-format@1.0.0 for format an exact decimal in engineering notation. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• format an exact decimal in engineering notation
• format a number in scientific notation
• round a decimal to significant digits for engineering display
• convert decimal text to normalized exponent notation
• show an SI prefix for an engineering exponent
• format extreme decimal exponents without floating point
• עיצוב מספר בכתיב הנדסי

Not supported

• locale-aware number formatting or digit grouping
• unit conversion or dimensional analysis
• parsing non-decimal numeric bases

Behavior

• Decimal input is parsed from text and all significand arithmetic uses strings and BigInt; binary floating point never represents the decimal value.
• Scientific notation has one coefficient digit before the point; engineering notation has one to three and an exponent divisible by three.
• The coefficient contains exactly significant_digits significant digits, including trailing zeros; zero is unsigned with exponent zero.
• half_even breaks exact ties toward an even final retained digit; half_up breaks ties away from zero; directed modes follow their named direction.
• include_si_prefix defaults to false. A prefix is returned only for engineering notation and a nonzero exponent with one NIST SI prefix symbol from -30 through 30.
• Canonical rendered notation is coefficient followed by lowercase e and an exponent with no plus sign or leading zeros.

Input

• value (string, required): min length 1; max length 1024; pattern ^[+-]?(?:(?:[0-9]+)(?:\.[0-9]+)?|\.[0-9]+)(?:[eE][+-]?[0-9]+)?$; Exact decimal text, optionally with a base-ten exponent.
• notation (one of "scientific", "engineering", required): Normalized scientific or engineering notation.
• significant_digits (integer, required): min 1; max 100; Exact count of significant digits in the coefficient.
• rounding_mode (one of "half_even", "half_up", "toward_zero", "away_from_zero", "floor", "ceiling", required): Explicit rule used when discarded digits are nonzero.
• include_si_prefix (boolean, optional): Request an SI prefix when the engineering exponent has one unambiguous symbol.

Output

• coefficient (string, required): min length 1; max length 102; pattern ^-?(?:0|[1-9][0-9]{0,2})(?:\.[0-9]+)?$; Normalized coefficient with exactly the requested significant digits.
• exponent (integer, required): min -1000000; max 1000000; Base-ten exponent.
• rendered (string, required): min length 3; max length 112; pattern ^-?(?:0|[1-9][0-9]{0,2})(?:\.[0-9]+)?e-?[0-9]+$; Canonical coefficient followed by e and the base-ten exponent.
• si_prefix (one of "q", "r", "y", "z", "a", "f", "p", "n", "µ", "m", "k", "M", "G", "T", "P", "E", "Z", "Y", "R", "Q", optional): Unambiguous SI prefix symbol for a nonzero engineering exponent.

Limits

• max input bytes: 1024
• max significant digits: 100
• max abs exponent: 1000000

Example

Request input:

{
  "value": "12345",
  "notation": "engineering",
  "significant_digits": 4,
  "rounding_mode": "half_even",
  "include_si_prefix": true
}

Response:

{
  "result": {
    "coefficient": "12.34",
    "exponent": 3,
    "rendered": "12.34e3",
    "si_prefix": "k"
  }
}

How to call it

MCP

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

{
  "id": "number-engineering-format",
  "version": "1.0.0",
  "input": {
    "value": "12345",
    "notation": "engineering",
    "significant_digits": 4,
    "rounding_mode": "half_even",
    "include_si_prefix": true
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/number-engineering-format/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"value":"12345","notation":"engineering","significant_digits":4,"rounding_mode":"half_even","include_si_prefix":true}'

The machine-readable contract is at /v1/tools/number-engineering-format/versions/1.0.0.

CLI

node cli.mjs run number-engineering-format 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

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