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Photography & video

Equivalent Focal Length Calculator

Find full-frame equivalent focal length using a crop factor.

Units clearly labeledCheck practical equipment limits
Photo & video desk
Photo & video desk

Match the sensor, lens and output settings to your equipment.

See the method

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Runs on your device

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Your result

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Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter actual focal length, crop factor.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

Input reference and sample values

Use the units and choices shown for each field. Sample values are provided for practice, not as recommendations.

InputFormat and unitsSample
Actual focal lengthNumeric value. Unit: mm. Must be greater than zero.35
Crop factorNumeric value. Must be greater than zero.1.5

Result for these sample inputs

52.5 mm

Select Try the example in the form to load these values and calculate them again. This replaces the current form inputs. Compare the result with the method and worked explanation below.

The method, explained

Equivalent focal length = actual focal length × crop factor.

A WORKED EXAMPLE

Using actual focal length = 35 mm, crop factor = 1.5, the result is 52.5 mm. Change these example inputs to match your task; use the method above to check each step.

What to keep in mind

Compares angle of view; does not physically change the lens focal length. An ideal geometric or exposure estimate. Lens behavior, stabilization, sensor crop and scene conditions may change practical results.

Methodology maintained by ClarityKit. How these tools are built and checked.