# Gx FoCalc — 35mm Crop Factor Calculator

> Calculates 35mm equivalent focal length and aperture for different camera formats. (iPhone/iPad app by Casey Cavanaugh.)

- Source: https://appshunter.io/ios/app/gx-focalc/id6612010267 (this page in markdown: same URL + `.md`)
- Developer: [Casey Cavanaugh](https://appshunter.io/developer/1761279780)
- Category: Photo & Video, Utilities
- Price: Free
- Rating: 5.00/5 from 6 App Store ratings · 2 written reviews indexed
- Age rating: 4+
- Requires: iOS 17.5 · 0 MB
- Languages: English
- Released: 2024-08-06
- Data updated: 2026-06-01
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/gx-focalc/id6612010267/reviews.md

## What is Gx FoCalc?

FoCalc by [Gx]Ace Is the internet's best 35mm Crop Factor Calculator.  Ever wonder what the 35mm equivalent of a 23mm f2 on APS-C would be?  Ever wonder what that 120mm f8 8x10 lens would be if it were put in 35mm terms?  Well now you can know it all with FoCalc!  FoCalc allows you to input a focal length and aperture as well as a focal reducer or teleconverter and automatically calculates the equivalent focal length and apparent aperture on 35mm Full Frame.

## Key features

- 35mm crop factor calculation
- Equivalent focal length
- Apparent aperture calculation
- Supports focal reducers
- Supports teleconverters

## Recent user reviews (2 of 2)

All indexed reviews: https://appshunter.io/ios/app/gx-focalc/id6612010267/reviews.md

### 4/5 — Great app, but…

*2026-01-19*

Love your YouTube videos and this app is pretty useful, but could we get custom focal reducer setting and/or add .8x to list of options? Great for those of us using Mamiya 645 lenses on GFX with Kipon focal reducer. Thank you and I look forward to your next YouTube videos.

### 5/5 — Always saving the day!

*2024-08-08*

From his cinematic reviews, to his god like presets, he has given a quick and efficient way of figuring out conversions fast. I’m not quite there to know the information for a custom entry so I do wish there would be a 6x8 option, as I am a frequent user and buyer of the Fuji GX680 series, but I will manage!

## Frequently asked questions about Gx FoCalc

### What is Gx FoCalc used for?

Gx FoCalc is a tool designed to help photographers and videographers calculate the 35mm equivalent focal length and apparent aperture when using different camera sensor sizes or lens accessories like focal reducers and teleconverters.

### How accurate is Gx FoCalc?

The app performs precise mathematical calculations based on the inputs provided. It is designed to be a reliable tool for understanding lens equivalencies across various camera formats.

### Does Gx FoCalc have ads?

No, Gx FoCalc does not contain advertisements. It offers an uninterrupted user experience for calculating crop factors and lens equivalencies.

### What devices does Gx FoCalc support?

Gx FoCalc is available for both iPhone and iPad devices, allowing users to perform calculations on their preferred Apple mobile device.

### How often is Gx FoCalc updated?

The app was last updated on August 7, 2024, with version 1.0.1. This indicates recent development and potential for future improvements and bug fixes.

### What is the age rating for Gx FoCalc?

Gx FoCalc has an age rating of 4+, making it suitable for users of all ages. This suggests the content and functionality are appropriate for a broad audience.

### Is Gx FoCalc free to use?

Yes, Gx FoCalc is completely free to download and use. There are no costs associated with accessing its features for calculating lens equivalencies.

### What do users like about Gx FoCalc?

Based on its 5.0-star rating from 6 reviews, users likely appreciate its straightforward functionality and accuracy in providing crop factor and aperture equivalencies.

## Version history (last 2 releases)

### 1.0.1 — 2024-08-07

V1.0.1 Changelog

- Adjusted Hamburger menu to account for Dynamic Island in use.

- Changed spacing of menu icon lines

- Changed text input field to follow system theme color.

- Altered App icon design

### 1.0 — 2024-08-06

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*