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

# Create UnitType

`POST /api/v3/unit-type`

## Request

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

Create UnitType.

## Request body

- CreateUnitTypeInput
  - `baseUnit` CreateBaseUnitInput, required
    - `aliases` string[], required: Alternative abbreviations for this unit, i.e. alternate symbols.
    - `name` string, required: The long-form name, e.g. "milliliter".
    - `symbol` string, required: The short-form label, e.g. "mL".
  - `formula` CreateFormulaUnitTermInput[]: Formula defining this type in terms of other units.
    - `exponent` integer, required: The exponent applied to the unit.
    - `value` string, required: The API ID of the unit in this formula term.
  - `name` string, required: The name of this unit type, e.g. "Volume".
  - `overrideIsConcentration` boolean, required: When true, forces this UnitType to be treated as a concentration type regardless of its terms. When false, the classification is determined by the UnitType's terms. Mutually exclusive with overrideIsContainerQuantity.
  - `overrideIsContainerQuantity` boolean, required: When true, forces this UnitType to be treated as a container quantity type regardless of its terms. When false, the classification is determined by the UnitType's terms. Mutually exclusive with overrideIsConcentration.

## Response `201`

Created

- UnitType: A UnitType is a dimensional category that groups inter-convertible `Unit` objects within Benchling's tenant-specific unit dictionary. Examples include Volume, Mass, Time, Molar Concentration, and custom types like Cell Concentration. Each UnitType has a designated `baseUnit` that serves as the reference for conversion factors of all other units in the type—units within the same UnitType can be converted to each other, but cross-dimensional conversions are not supported. The dimensional composition is described by `terms` (see `UnitTypeTerm`), and derived types can specify their `formula` (see `FormulaUnitTerm`) to define relationships like Liter = decimeter³. UnitTypes can be flagged to provide concentration units or container quantity units for inventory features regardless of their dimensional terms. Historically called "Quantity" in some internal systems.
  - `__typename` string
  - `archiveReason` string, nullable
  - `archived` boolean
  - `baseUnit` UnitRef
    - `__typename` string
    - `id` string, api_id
  - `createdAt` string, datetime, nullable
  - `formula` FormulaUnitTerm[], nullable: Defines this unit type in terms of other units for derived types, e.g. Liter = decimeter cubed.
    - `__typename` string
    - `exponent` integer
    - `value` UnitRef
      - `__typename` string
      - `id` string, api_id
  - `id` string
  - `modifiedAt` string, datetime, nullable
  - `name` string: The user-facing name, e.g. "Volume" or "Molar Concentration".
  - `overrideIsConcentration` boolean, nullable: When true, forces this UnitType to be treated as a concentration type regardless of its terms. When false, the classification is determined by the UnitType's terms. Mutually exclusive with `overrideIsContainerQuantity`.
  - `overrideIsContainerQuantity` boolean, nullable: When true, forces this UnitType to be treated as a container quantity type regardless of its terms. When false, the classification is determined by the UnitType's terms. Mutually exclusive with `overrideIsConcentration`.
  - `terms` UnitTypeTerm[]: The dimensional composition of this unit type as a list of SI base dimensions with exponents.
    - `__typename` string
    - `exponent` integer
    - `value` 'TIME' | 'LENGTH' | 'MASS' | 'CURRENT' | 'TEMPERATURE' | 'AMOUNT' | 'LUMINOUS_INTENSITY'
  - `units` string, uri, nullable: All units belonging to this unit type.

## 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)