---
title: "Retro 15C - Reviews, Revenue and Downloads in United States | Apple App Store"
description: "Students and scientists from the 1980s will remember the classic RPN scientific calculators. These calculators strike a perfect balance between functionality and complexity.  * Complex number arithmet"
---

# Retro 15C — United States

![Retro 15C App Icon](https://is1-ssl.mzstatic.com/image/thumb/Purple82/v4/77/50/98/775098f7-0f10-d8f5-1517-9720bb7c6c60/mzl.vdfexbhv.png/400x400bb.png)

**Developer:** [Greg Hewgill](https://apptail.io/developer/greg-hewgill-rpmb)
**Category:** Utilities
**Rating:** 4.3/5 (223 ratings)
**Price:** Free
**Bundle ID:** com.hewgill.Free15c
**Store:** Apple App Store
**Country:** United States
**Version:** 1.1 (released 2017-04-27)
**Original Release:** 2012-12-15

**App Store Link:** [Download on Apple App Store](https://apps.apple.com/us/app/app/id583559000)
**AppTail Page:** [https://apptail.io/app/retro-15c-aYc/united-states](https://apptail.io/app/retro-15c-aYc/united-states)

## Retro 15C Description
Students and scientists from the 1980s will remember the classic RPN scientific calculators. These calculators strike a perfect balance between functionality and complexity.

* Complex number arithmetic and trig functions
* Matrix calculations
* Numerical root finder
* Numerical integration
* Statistical functions, linear regression
* Fully programmable

This app is completely free, no ads or extra bits to buy. I love this calculator and I like to share.

## Retro 15C Screenshots
- [Screenshot 1](https://is1-ssl.mzstatic.com/image/thumb/Purple111/v4/2c/2f/8f/2c2f8fad-5749-d75b-4dc5-670611a861e0/pr_source.png/2208x1242.png)
- [Screenshot 2](https://is1-ssl.mzstatic.com/image/thumb/Purple111/v4/22/ee/42/22ee4220-42ac-0592-70fd-22c448e83c7c/pr_source.png/2208x1242.png)

## Retro 15C Rating Breakdown in United States
- 5 stars: 166 (74%)
- 4 stars: 13 (6%)
- 3 stars: 16 (7%)
- 2 stars: 7 (3%)
- 1 stars: 21 (9%)

## Retro 15C Reviews in United States

### ****- "iPhone 17"
It’s apparently not possible to close the screen, or close the app on the iPhone 27, which has virtual handles on the screen corners. You must turn off the screen and then switch. Thanks for your support. 
I hope you can fix this, as I have enjoyed the app for many years.
-- Olemax II, 2026-03-17

### *---- "Bad app"
Locks my iPhone in landscape mode, next to impossible to exit app
-- vince from MD, 2025-11-04

### ***** "An old friend"
I was delighted to find this.  I still own, and use, both 40 year old 15C and 12C calculators I acquired working at the HP IC fab that made chips for them.  Thanks for bringing the 15C to my iPhone!
-- tonymaxf, 2025-09-05

### ***-- "Good, but no way out"
As far as a HP11, it’s fine. But, there is no exit button, half swipe up app switcher fails also
-- BLTomi, 2025-08-25

### ***** "Just the best thing!"
Appreciate the work to keep the app current.
-- Camper Monte Sano, 2025-02-06

### ***** "Engineering must"
I’ve been using this for many years in my work. Love it. Except, this week, the entire screen started to blink. Is there a fix?
-- PSU Mark, 2024-10-31

### ***** "Fantastic"
If you know, you know…
-- Phonograph, 2024-10-05

### ***** "An Old Friend now on my phone"
Near perfection.  The only thing I wish they would do is to add haptic feedback on the keyboard.  Well done , guys.
-- Catswold, 2024-09-16

### ***** "Still working on iOS 18"
Just like the original calculator that I used as I got my PhD in physics. The best by HP.
-- Raman Pfaff, 2024-09-16

### ***** "My go to calculator for years"
After a few bumps with the loss of a home button, this is back.  Thank goodness!
-- Persnicketyone, 2024-06-18

[View all Retro 15C reviews and detailed analytics on AppTail](https://app.apptail.io/signup?utm_campaign=ai-crawl&utm_content=reviews)



## Retro 15C Discovered Keywords
- rpn calc
- hp financial calculator
- rpn
- hp41cv
- rpn calculator free
- rpn scientific calculator
- rlm-12cx
- retro 15c
- hp 12c financial calculator
- free42

## Apps Similar to Retro 15C
- [jCalc – Taschenrechner](https://apptail.io/app/jcalc-taschenrechner-dyLb/united-states)
- [PCalc](https://apptail.io/app/pcalc-fLFc/united-states)
- [Geomulator](https://apptail.io/app/geomulator-fXkd/united-states)
- [Complex RPN Calculator](https://apptail.io/app/complex-rpn-calculator-kUnd/united-states)
- [PCalc Lite](https://apptail.io/app/pcalc-lite-JYKd/united-states)
- [TechniCalc Calculator](https://apptail.io/app/technicalc-calculator-wqSd/united-states)
- [Free42](https://apptail.io/app/free42-Oxve/united-states)
- [GO-21 SciRPN](https://apptail.io/app/go-21-scirpn-SGEe/united-states)
- [x36](https://apptail.io/app/x36-ZJNf/united-states)
- [SwiftRPN](https://apptail.io/app/swiftrpn-bTMq/united-states)

## Retro 15C Available In
- [United States](https://apptail.io/app/retro-15c-aYc/united-states)
- [Canada](https://apptail.io/app/retro-15c-aYc/canada)
- [France](https://apptail.io/app/retro-15c-aYc/france)
- [Australia](https://apptail.io/app/retro-15c-aYc/australia)
- [Germany](https://apptail.io/app/retro-15c-aYc/germany)
- [Sweden](https://apptail.io/app/retro-15c-aYc/sweden)
- [Denmark](https://apptail.io/app/retro-15c-aYc/denmark)
- [Switzerland](https://apptail.io/app/retro-15c-aYc/switzerland)
- [United Kingdom](https://apptail.io/app/retro-15c-aYc/united-kingdom)
- [Netherlands](https://apptail.io/app/retro-15c-aYc/netherlands)
- [Norway](https://apptail.io/app/retro-15c-aYc/norway)
- [Japan](https://apptail.io/app/retro-15c-aYc/japan)
- [Brazil](https://apptail.io/app/retro-15c-aYc/brazil)
- [Spain](https://apptail.io/app/retro-15c-aYc/spain)
- [Italy](https://apptail.io/app/retro-15c-aYc/italy)
- [New Zealand](https://apptail.io/app/retro-15c-aYc/new-zealand)
- [Mexico](https://apptail.io/app/retro-15c-aYc/mexico)
- [China](https://apptail.io/app/retro-15c-aYc/china)
- [Russia](https://apptail.io/app/retro-15c-aYc/russia)
- [Finland](https://apptail.io/app/retro-15c-aYc/finland)
- [Hong Kong SAR China](https://apptail.io/app/retro-15c-aYc/hong-kong)
- [Belgium](https://apptail.io/app/retro-15c-aYc/belgium)
- [Austria](https://apptail.io/app/retro-15c-aYc/austria)
- [Ireland](https://apptail.io/app/retro-15c-aYc/ireland)
- [Singapore](https://apptail.io/app/retro-15c-aYc/singapore)
- [Croatia](https://apptail.io/app/retro-15c-aYc/croatia)
- [Algeria](https://apptail.io/app/retro-15c-aYc/algeria)
- [Madagascar](https://apptail.io/app/retro-15c-aYc/madagascar)
- [Chile](https://apptail.io/app/retro-15c-aYc/chile)
- [Greece](https://apptail.io/app/retro-15c-aYc/greece)
- [Israel](https://apptail.io/app/retro-15c-aYc/israel)
- [Nigeria](https://apptail.io/app/retro-15c-aYc/nigeria)
- [Poland](https://apptail.io/app/retro-15c-aYc/poland)
- [Angola](https://apptail.io/app/retro-15c-aYc/angola)
- [Argentina](https://apptail.io/app/retro-15c-aYc/argentina)
- [Azerbaijan](https://apptail.io/app/retro-15c-aYc/azerbaijan)
- [Barbados](https://apptail.io/app/retro-15c-aYc/barbados)
- [Bulgaria](https://apptail.io/app/retro-15c-aYc/bulgaria)
- [Brunei](https://apptail.io/app/retro-15c-aYc/brunei)
- [Botswana](https://apptail.io/app/retro-15c-aYc/botswana)
- [Belarus](https://apptail.io/app/retro-15c-aYc/belarus)
- [Belize](https://apptail.io/app/retro-15c-aYc/belize)
- [Colombia](https://apptail.io/app/retro-15c-aYc/colombia)
- [Cyprus](https://apptail.io/app/retro-15c-aYc/cyprus)
- [Czechia](https://apptail.io/app/retro-15c-aYc/czechia)
- [Dominican Republic](https://apptail.io/app/retro-15c-aYc/dominican-republic)
- [Ecuador](https://apptail.io/app/retro-15c-aYc/ecuador)
- [Estonia](https://apptail.io/app/retro-15c-aYc/estonia)
- [Egypt](https://apptail.io/app/retro-15c-aYc/egypt)
- [Hungary](https://apptail.io/app/retro-15c-aYc/hungary)
- [Indonesia](https://apptail.io/app/retro-15c-aYc/indonesia)
- [India](https://apptail.io/app/retro-15c-aYc/india)
- [Iceland](https://apptail.io/app/retro-15c-aYc/iceland)
- [South Korea](https://apptail.io/app/retro-15c-aYc/south-korea)
- [Kuwait](https://apptail.io/app/retro-15c-aYc/kuwait)
- [Kazakhstan](https://apptail.io/app/retro-15c-aYc/kazakhstan)
- [Lebanon](https://apptail.io/app/retro-15c-aYc/lebanon)
- [Luxembourg](https://apptail.io/app/retro-15c-aYc/luxembourg)
- [Latvia](https://apptail.io/app/retro-15c-aYc/latvia)
- [Macao SAR China](https://apptail.io/app/retro-15c-aYc/macau)
- [Malta](https://apptail.io/app/retro-15c-aYc/malta)
- [Mauritius](https://apptail.io/app/retro-15c-aYc/mauritius)
- [Malaysia](https://apptail.io/app/retro-15c-aYc/malaysia)
- [Paraguay](https://apptail.io/app/retro-15c-aYc/paraguay)
- [Romania](https://apptail.io/app/retro-15c-aYc/romania)
- [Saudi Arabia](https://apptail.io/app/retro-15c-aYc/saudi-arabia)
- [Slovenia](https://apptail.io/app/retro-15c-aYc/slovenia)
- [Slovakia](https://apptail.io/app/retro-15c-aYc/slovakia)
- [Thailand](https://apptail.io/app/retro-15c-aYc/thailand)
- [Türkiye](https://apptail.io/app/retro-15c-aYc/turkey)
- [Taiwan](https://apptail.io/app/retro-15c-aYc/taiwan)
- [Ukraine](https://apptail.io/app/retro-15c-aYc/ukraine)
- [Uzbekistan](https://apptail.io/app/retro-15c-aYc/uzbekistan)
- [Vietnam](https://apptail.io/app/retro-15c-aYc/vietnam)
- [South Africa](https://apptail.io/app/retro-15c-aYc/south-africa)
- [Nepal](https://apptail.io/app/retro-15c-aYc/nepal)
- [Peru](https://apptail.io/app/retro-15c-aYc/peru)
- [Philippines](https://apptail.io/app/retro-15c-aYc/philippines)
- [Pakistan](https://apptail.io/app/retro-15c-aYc/pakistan)
- [United Arab Emirates](https://apptail.io/app/retro-15c-aYc/united-arab-emirates)
- [Portugal](https://apptail.io/app/retro-15c-aYc/portugal)
- [Nicaragua](https://apptail.io/app/retro-15c-aYc/nicaragua)
- [North Macedonia](https://apptail.io/app/retro-15c-aYc/north-macedonia)
- [Namibia](https://apptail.io/app/retro-15c-aYc/namibia)
- [Panama](https://apptail.io/app/retro-15c-aYc/panama)
- [Tunisia](https://apptail.io/app/retro-15c-aYc/tunisia)
- [Cayman Islands](https://apptail.io/app/retro-15c-aYc/cayman-islands)
- [Jamaica](https://apptail.io/app/retro-15c-aYc/jamaica)
- [Uganda](https://apptail.io/app/retro-15c-aYc/uganda)
- [Grenada](https://apptail.io/app/retro-15c-aYc/grenada)
- [Senegal](https://apptail.io/app/retro-15c-aYc/senegal)
- [Qatar](https://apptail.io/app/retro-15c-aYc/qatar)
- [Uruguay](https://apptail.io/app/retro-15c-aYc/uruguay)

---

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