Last 30 days
Last 30 days
Avg per download
19 reviews
Last 30 days
Last 30 days
Avg rev. per download
19 reviews
Performance Insights
Category rankings
Competition level
Low competitionUnder 100K on both downloads and revenue — the kind of niche a small team can still take.
On the store
Released May 2014 · 12 releases since
Gamma Calculator Pro is an iOS app ($3.99) by Gerrit kleyn Winkel in the business category, holding #16 in the paid business charts. It holds a 3.6-star rating.
- A paid app priced at $3.99.
- Ships new versions a few a year.
- Latest version is 2.7.1, released March 20, 2026.
- 47% of ratings are five-star.
- Available in 1 language.
- Strongest in US, IT, KR.
- Downloads at 2.9 MB and requires iOS 18.6+.
- Rated 18+.
App details
- Version
- 2.7.1
- Release status
- Worldwide
- Age rating
- 18+
- Requires
- iOS 18.6+
- Size
- 2.9 MB
- Languages
- English
- Price
- $3.99
- First seen
- May 2014
- Top markets
- US, IT, KR
- Publisher country
- Netherlands
- Support
- Visit support
Release history
12 versions tracked
- Version 2.7.1Latest
- Version 2.7.0
- Version 2.6.2
- Version 2.6.1
- Version 2.6
- Version 2.5
- Version 1.5
- Version 1.4
- Version 1.3
- Version 1.2
- Version 1.1
- Version 1.0
Ships a few a year.
What users say
- 4.0
Works well
The app works well on IPhone if you know what you’re doing and double checking it. There are a few mistakes with the schedule thicknesses in the calculator where some measurements are missing decimal places in front so the distance is over a hundred feet.
Reviewed on version 1.5
- 5.0
A reliable app for I-phone
Between this app and another calculator app (x-ray_timer) I would say my whole shop uses this app for anyone that owns an I-phone. What drives me crazy is when you initially want to change the curie amount and the line always starts in the front of the initial number. Just an extra step moving the line to select the initial number and change it. We use this app every week here in Kansas.
Reviewed on version 2.6.1
- 4.0
Requested changes
Can you please add the R factor for D3. Also could you please make it so that the SFD and other measurements that need to be precise don’t round up or down?
About Gamma Calculator Pro
796 characters
Save time with this exposure calculator for Iridium-192, Selinium-75 and Cobalt-60 sources. No more need to calculate the formula or use of the "old-school plastic calculator" Simply fill in the thickness, activity(in Curies) and source-film-distance and you get the correct exposure time.
R factor for different densities and film types.
For materials: Iron(steel), Concrete, Tungsten, Lead, Aluminum, Titanium, Copper, Zinc, Brass, Inconel X, Zirconium and Uranium.
Features:
- Exposure Time calculator - Geometric Unsharpness calculator - Exposure Correction calculator - Decay calculator - Barricade calculator - Pipe Schedule selector (single/double wall) - Weld enforcement setting - Iridium 192 Emissivity setting - inch/mm setting
Screenshots
5 iPhone screenshots
Gamma Calculator Pro iOS app is available. The app maintains a 3.6-star rating based on 19 user reviews, indicating decent user acceptance in the mobile app market.
Gamma Calculator Pro iOS app competes actively in the mobile app category.
You can download Gamma Calculator Pro iOS app from the App Store for iOS devices, requiring iOS 18.6 or later. The app provides its core features without requiring in-app purchases.
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