---
title: "Crop Factor / Equivalent Focal Length Calculator"
method: POST
path: "/api/v1/tools/crop-factor-calculator"
tags: ["photography"]
---

# Crop Factor / Equivalent Focal Length Calculator

`POST /api/v1/tools/crop-factor-calculator`

## Request

- Base URL: `https://calcfleet.com`
- URL: `https://calcfleet.com/api/v1/tools/crop-factor-calculator`
- Auth: none declared

Convert focal length to a full-frame equivalent by crop factor. Enter focal length, aperture, and sensor to get equivalent focal, aperture, and field of view.

## Request body

- object
  - `focalMm` number, required
  - `aperture` number, required
  - `sensorPreset` 'full-frame' | 'aps-c' | 'aps-c-canon' | 'mft' | 'custom', required
  - `cropFactor` number, required
  - `sensorWidthMm` number, required

## Response `200`

Successful calculation result.

- object
  - `result` object, required: Structured calculation output (fields vary per calculator).

## Other responses

- `400`: Invalid input — the issues array contains Zod validation errors.
- `403`: Forbidden — an Authorization: Bearer cf_… key was supplied but is invalid.
- `404`: Unknown tool slug.

---

[API](https://skmtc.dev/calcfleet/apis/calcfleet-financial-calculators-api.md) · [All operations](https://skmtc.dev/calcfleet/apis/calcfleet-financial-calculators-api/llms.txt) · [OpenAPI document](https://skmtc.dev/calcfleet/apis/calcfleet-financial-calculators-api/revisions/cd9abd595bbe?raw)