Unit Converter — Length, Weight, Temperature & More, Alias-Tolerant

Convert physical units by API without memorizing canonical spellings: kg, kilos, kilogramme, KG all work. Categories cover length, weight, temperature (real formulas, not factors), volume, area and more — and every conversion also returns the value in every sibling unit of its category, so one call answers all the follow-ups. Up to 50 conversions per run, online, by API, or as an agent tool via Apify MCP.

Results are float-noise-free (12-significant-digit cleanup — you get 62.1371192237, never 62.13711922369999).

What you get

• result — the requested conversion, noise-cleaned
• allUnits — the value in every unit of the category (100 km → meters, feet, miles, nautical miles... in one record)
• category + canonical from/to (so you see how your alias resolved)
• Temperature uses the actual formulas (F/C/K/Rankine) — 212°F is exactly 100°C, asserted by our release test
• Fail-soft: unknown units and incompatible categories (kg → miles) never fail the run — {ok: false, error} naming the problem, never charged.

Input

{ "value": 100, "from": "km", "to": "miles" }

Bulk: { "items": [{ "value": 212, "from": "fahrenheit", "to": "celsius" }, { "value": 2.5, "from": "kg", "to": "lb" }] }

Output (real run, trimmed)

{
  "value": 100,
  "ok": true,
  "from": "kilometer",
  "to": "mile",
  "result": 62.1371192237,
  "category": "length",
  "allUnits": { "meter": 100000, "kilometer": 100, "mile": 62.1371192237, "foot": 328083.989501, "nautical-mile": 53.9956803456 }
}

Pricing

$0.0004 per conversion — sibling-unit table included. Unknown/incompatible units are never charged.

Measured against the direct incumbent (2026-08-07): moving_beacon/unit-converter-input charges $0.001 per item — this is under half that.

Honest limits

• Physical measurement units only — no currency (rates change hourly; a static table would lie) and no timezone math (see our timestamp-converter).
• Incompatible categories are rejected with both categories named, never coerced.
• Precision: factors carry standard reference values (e.g. pound = 453.59237 g exactly); 12 significant digits returned.

FAQ

Which aliases work? The natural ones per unit — abbreviations (kg, oz, mi), plurals, and common spellings (kilogramme, metre). The output shows the canonical unit your alias resolved to.

Why is temperature special? Because °F→°C is an affine formula, not a ratio — converters that treat it as a factor are simply wrong. This one implements the formulas and the release test proves 212°F = 100°C.

What's allUnits for? Dashboards and agents: one conversion call gives the value in the whole category, so you render metric + imperial without a second request.

Ton vs tonne? All three are distinct and supported: us-ton (short), imperial-ton (long), metric-ton (tonne) — aliases route ton→US, tonne→metric.

Why did some rows come back ok: false? An unknown unit spelling, or a cross-category request like kg→miles — the error names exactly what happened. Never charged.

Use from code or AI agents

curl -s "https://api.apify.com/v2/acts/EliAI~unit-converter/run-sync-get-dataset-items?token=$APIFY_TOKEN" \
  -X POST -H 'Content-Type: application/json' \
  -d '{"items": [{"value": 5, "from": "miles", "to": "km"}, {"value": 350, "from": "F", "to": "C"}]}'

Agents: connect Apify MCP and call the EliAI/unit-converter tool.

• Capability: alias-tolerant physical-unit conversion with per-category sibling tables and formula-correct temperature
• Required input: value + from + to, or items array
• Returns: one record per conversion; result + allUnits are the payload
• Bounded: 50 conversions per run; failures isolate per item
• Side effects: none