Duration add

duration-add · version 1.0.0 · Dates & times (UTC, ISO 8601) · free, no key needed

Sum mixed SI duration terms in nanoseconds and return the exact rational in a target unit.

Use when you need to: duration add · add duration terms · sum mixed duration units.

Supported

• duration add
• add duration terms
• sum mixed duration units

Not supported

• months
• years
• weeks
• leap seconds
• ISO-8601 duration strings
• average duration
• floats

Behavior

• terms is a non-empty list of at most 32 {value, unit} duration amounts.
• Each value is a canonical integer string; unit is one of ns, us, ms, s, min, h, day.
• Terms are converted to nanoseconds with BigInt, summed, then expressed in the to unit as a reduced rational.
• day is exactly 86400 seconds; negative terms are allowed; leap seconds are not applied.
• Input integers and the reduced numerator and denominator may have at most 1000 digits excluding sign.

Input

• terms (array of object, required): min items 1; max items 32
• to (one of "ns", "us", "ms", "s", "min", "h", "day", required)

Output

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

Limits

• max digits: 1000
• max terms: 32
• units: ["ns","us","ms","s","min","h","day"]

Example

Request input:

{
  "terms": [
    {
      "value": "1",
      "unit": "min"
    },
    {
      "value": "30",
      "unit": "s"
    }
  ],
  "to": "s"
}

Response:

{
  "result": {
    "numerator": "90",
    "denominator": "1"
  }
}

How to call it

MCP

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

{
  "id": "duration-add",
  "version": "1.0.0",
  "input": {
    "terms": [
      {
        "value": "1",
        "unit": "min"
      },
      {
        "value": "30",
        "unit": "s"
      }
    ],
    "to": "s"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/duration-add/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"terms":[{"value":"1","unit":"min"},{"value":"30","unit":"s"}],"to":"s"}'

The machine-readable contract is at /v1/tools/duration-add/versions/1.0.0.

CLI

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

Get the client at /clients/cli/.

Related tools

• Duration convert: Convert a canonical integer duration between nanosecond-based SI units as an exact rational.
• Duration compare: Compare two SI duration amounts after converting both to nanoseconds.
• ISO date add: Add a signed whole-day delta to a strict YYYY-MM-DD calendar date.
• ISO date add months: Add a signed month count to a YYYY-MM-DD date, clamping the day to the target month.
• ISO date add years: Add a signed whole-year delta to a YYYY-MM-DD date, clamping the day if 29 February has no match.
• ISO date business day add: Add a signed count of business days to a date, skipping caller-supplied weekend weekdays and holidays.