---
title: "Create Unit"
method: POST
path: "/api/v3/unit"
tags: ["Unit"]
---

# Create Unit

`POST /api/v3/unit`

## Request

- Base URL: `https://{tenant_name}.benchling.com`
- URL: `https://{tenant_name}.benchling.com/api/v3/unit`
- Auth: HTTP bearer

Create Unit.

## Request body

- CreateUnitInput
  - `aliases` string[], required: Alternative abbreviations for this unit, e.g. alternate symbols.
  - `conversionFactor` string, decimal, required: Conversion factor relative to the UnitType's base unit.
  - `name` string, required: The long-form name, e.g. "milliliter".
  - `symbol` string, required: The short-form label, e.g. "mL".
  - `unitTypeId` string, required: The API ID of the UnitType this unit belongs to.

## Response `201`

Created

- Unit: A Unit is a specific measure of a physical quantity within Benchling's tenant-specific unit dictionary, used to capture and convert scientific measurements across the platform. Each Unit belongs to a `UnitType` (e.g., "Volume" or "Mass") and defines its relationship to the UnitType's base unit through a `conversionFactor`. For example, a milliliter unit would have a conversionFactor of 0.001 relative to a liter base unit. Units are identified by a human-readable `name` (e.g., "milliliter"), a shorthand `symbol` (e.g., "mL"), and may have `aliases` for alternate input symbols. Units within the same UnitType are inter-convertible; cross-dimensional conversions are not supported. Units appear throughout Benchling wherever measurements are recorded, including inventory container quantities (see `Measurement`), result fields, and sample properties.
  - `__typename` string
  - `aliases` string[]: Any additional short-form labels that should be recognized in input
  - `archiveReason` string, nullable
  - `archived` boolean
  - `conversionFactor` string, decimal: Conversion factor relative to the UnitType's baseUnit. E.g. for a kilometer, the baseUnit is meter and the conversionFactor is 1000.
  - `createdAt` string, datetime, nullable
  - `id` string
  - `modifiedAt` string, datetime, nullable
  - `name` string: Default long-form identifier, e.g. "meter".
  - `symbol` string: Default short-form label, e.g. "m" for meter.
  - `unitType` UnitTypeRef
    - `__typename` string
    - `id` string, api_id

## Other responses

- `400`: Bad Request
- `403`: Forbidden
- `404`: Not Found
- `409`: Conflict
- `429`: Too Many Requests
- `500`: Internal Server Error

---

[API](https://skmtc.dev/benchling/apis/benchling-api.md) - [All operations](https://skmtc.dev/benchling/apis/benchling-api/llms.txt) - [OpenAPI document](https://skmtc.dev/benchling/apis/benchling-api/revisions/c9f087b98b8b?raw)