# HP 15c Calculator vs Smart Adding Machine

The clearest difference is price: Smart Adding Machine at $3.99 against HP 15c Calculator's $14.99. Smart Adding Machine also leads on update cadence (every 3 weeks vs every 16 months). HP 15c Calculator's advantage is iOS requirement (15.6 vs 17.0). On ads, in-app purchases and device support there is nothing between them.

HP 15c Calculator costs $14.99 and Smart Adding Machine $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

HP 15c Calculator ships an update every 16 months, Smart Adding Machine every 3 weeks. The most recent releases landed on September 30, 2026 and September 9, 2026 respectively.

## The numbers

| Metric | HP 15c Calculator | Smart Adding Machine |
| --- | --- | --- |
| Price | $14.99 | **$3.99** |
| Rating | **[4.8 (207 ratings)](https://appshunter.io/ios/app/hp-15c-calculator/id503720774/reviews)** | — |
| Number of ratings | **207** | — |
| Positive reviews | 68.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 16 months | **Every 3 weeks** |
| Monetization | Paid | — |
| Size | 45 MB | 0 MB |
| Requires iOS | **15.6** | 17.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac |
| Age rating | 4+ | 4+ |
| Developer | [MORAVIA Consulting, spol. s r.o.](https://appshunter.io/developer/1673101600) | [Harry Detrick](https://appshunter.io/developer/1698895959) |

## What reviewers say

### HP 15c Calculator

[App page](https://appshunter.io/ios/app/hp-15c-calculator/id503720774)

Experience the official emulator of the legendary HP 15c scientific calculator. This app offers a redesigned interface and modern look while preserving the precision and reliability of the original. It features RPN input, matrix calculations, complex functions, and numerical integration for professionals and students.

**Highlights:** Official HP 15c emulator, RPN (Reverse Polish Notation), Matrix calculations, Complex functions, Numerical integration, Programmable (448 lines)

**Features:** Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 🚀 Excellent emulation of original HP 15C
- 👍 Faithful reproduction of classic calculator
- 👍 Includes original manual
- 👍 Works just like the real thing
- 👍 Vertical layout with key features

**What reviewers complain about**

- 🐛 Display issues in portrait mode
- 🐛 Bugs with programming and trig functions
- 🔇 Loud button click sound
- 💰 Expensive for an app

**Reported bugs**

- Numbers not aligned in display window
- Display flashing after running programs
- Incompatibility with latest iOS versions

**Requested features**

- Copy and paste functionality
- Ability to change calculator models
- Option to disable button click sound
- Better support for larger iPhone screens


### Smart Adding Machine

[App page](https://appshunter.io/ios/app/smart-adding-machine/id6452400755)

**In-app purchases:** none


## Frequently asked questions

### Is HP 15c Calculator free?

HP 15c Calculator costs $14.99, with no in-app purchases.

### Is Smart Adding Machine free?

Smart Adding Machine costs $3.99, with no in-app purchases.

### Do HP 15c Calculator or Smart Adding Machine have ads?

Neither HP 15c Calculator nor Smart Adding Machine shows ads.

### Which is updated more often, HP 15c Calculator or Smart Adding Machine?

HP 15c Calculator ships an update every 16 months, and Smart Adding Machine every 3 weeks. Most recently, HP 15c Calculator was updated on September 30, 2026 and Smart Adding Machine on September 9, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*