# Gamma Calculator Pro — user reviews > 17 indexed App Store user reviews of Gamma Calculator Pro by Gerrit kleyn Winkel, rated 3.60/5 from 19 ratings. - Source: https://appshunter.io/ios/app/gamma-calculator-pro/id867478383/reviews - App overview in markdown: https://appshunter.io/ios/app/gamma-calculator-pro/id867478383.md - Rating breakdown: 5★ 9 · 4★ 3 · 3★ 1 · 2★ 2 · 1★ 4 ## Most critical reviews (10 lowest-rated) ### 1/5 — Fix it! *2022-09-26* This thing worked like a dream for years but since the update…it’s junk. Won’t even configure time on iPhone! Fix it or refund my purchase. ### 1/5 — 아이폰 안되 *2022-09-26* 4.1 업데이트 후에 안되요 글씨 안보여 ### 1/5 — 허접 *2016-01-05* 안드로이드 버전에 비해 조잡하고 최적화도 안되어 있으면서 인치단위라 불편 ### 2/5 — 24” Schedule 40 *2022-04-10* App is great for getting shot times. Now…24” 40s and 24” schedule 40 are 2 different thicknesses. 24” 40S is a .375 24” Sch 40 is a .688 I learned the hard way to figure that one out. ### 2/5 — No D3 AGFA *2019-03-26* No D3 AGFA in R factor chart everything else is great though. If you could add it that would be awesome! ### 2/5 — Plz update TT *2019-01-16* Apk ver both iso ver many funcion difficult ### 3/5 — What's up w/ Gadolinium *2017-10-19* I run a LIXI scanner often which uses Gadolinium. The decay calculator will calculate all the listed sources but won't calculate for Gad. What gives!? ### 3/5 — Auto SFD feature corrupt *2016-04-12* Great app. Use it everyday. The new update does not seem to be working correctly. Selecting double wall thickness leads to an error in the calculator. Please explain more clearly how to use the calculator and R factors. Do the R factor densities refer to the weld or parent material? ### 4/5 — Requested changes *2024-02-22* 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? ### 4/5 — Works well *2023-12-16* 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. ## Most praised reviews (7 highest-rated) ### 5/5 — A reliable app for I-phone *2024-12-07* 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. ### 5/5 — App update *2022-09-26* Love the app, have been using it for years, but as of today the app will not work on my iPhone after the IOS 16 update. Please fix ### 5/5 — Love this app *2019-04-15* Use this everyday, best app for X-ray personnel. I wish the maker of this app would do a code app like b31.3, section 8, api 1104. ### 5/5 — Great app *2018-06-27* An amazing tool for anybody in Industrial Radiography. I highly recommend it. ### 5/5 — Worth it *2016-09-27* This is worth the money for an on the go industrial radiographer! Better than a slider even though your trusting someone else with your shot times it's never steered me wrong. Great job on the app hope you keep up with the changing of times. Thanks **Developer response:** Thank you! But as your said, always be carefull with the results. ### 5/5 — plz update *2016-01-31* i want show minute, second ex)2m34s ### 4/5 — R-factor *2022-08-18* The R-factor for AFGA D3 isn’t listed. I would like to know if this will ever be added or fixed. I love the app, but this is the problem I have with it. --- *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 2026-09-09.*