# Complex RPN Calculator vs ODE Solver +

The clearest difference is ads: Complex RPN Calculator at none against ODE Solver +'s shown. Complex RPN Calculator also leads on monetization model (free vs ad-supported) and ratings volume (24 vs 4). ODE Solver +'s advantage is update cadence (weekly vs every 5 months) and iOS requirement (14.0 vs 16.4). On price, rating, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 3.9 for Complex RPN Calculator against 4.0 for ODE Solver +. That said, the two scores are not equally well evidenced: Complex RPN Calculator has 24 ratings behind it against 4, so its average is the more settled of the two.

Complex RPN Calculator ships an update every 5 months, ODE Solver + weekly. The most recent releases landed on October 21, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Complex RPN Calculator | ODE Solver + |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [3.9 (24 ratings)](https://appshunter.io/ios/app/complex-rpn-calculator/id291826330/reviews) | **[4.0 (4 ratings)](https://appshunter.io/ios/app/ode-solver-plus/id1549447510/reviews)** |
| Number of ratings | **24** | 4 |
| Positive reviews | 51.7% of reviews | — |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | Every 5 months | **Weekly** |
| Monetization | **Free** | Ad-supported |
| Size | 1 MB | 11 MB |
| Requires iOS | 16.4 | **14.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [John Coddington](https://appshunter.io/developer/291826333) | [Takahiko Nakade](https://appshunter.io/developer/1513184888) |

## What reviewers say

### Complex RPN Calculator

[App page](https://appshunter.io/ios/app/complex-rpn-calculator/id291826330)

This scientific calculator utilizes a four-level stack and natively handles complex numbers. It allows users to input and view numbers in both polar and rectangular formats, remembering its state and offering 10 memory locations.

**Highlights:** Complex number support, Four-level stack, Polar and rectangular formats, State persistence, 10 memory locations, Scientific calculations

**Features:** macOS Compatibility

**In-app purchases:** none

**What reviewers like**

- ✅ Great RPN functionality
- ✨ Complex number support
- 🆓 Free to use
- 🚫 No ads or in-app purchases
- 💻 Works on macOS

**What reviewers complain about**

- 🎨 SwiftUI design is ugly
- 🐌 Slow keyboard response
- 🖱️ Clunky operation
- 📉 Complex number operations limited
- ⚠️ Broken on newer iOS versions (historically)

**Reported bugs**

- Mutes other apps when used
- Slow keyboard response after update
- X^3 calculation incorrect for large imaginary numbers
- App crashes on opening/button press (historical iOS 9 issues)
- App starts upside down in landscape on iPad (historical iOS 8 issue)

**Requested features**

- Turn off key click sound
- Customize number display
- See the stack
- Fix slow entry response
- Fix imaginary number calculation (X^3)


### ODE Solver +

[App page](https://appshunter.io/ios/app/ode-solver-plus/id1549447510)

This utility app calculates ordinary differential equations using the Runge-Kutta method. It offers a step width of 0.01 for its calculations.

**Highlights:** Ordinary differential equation calculation, Runge-Kutta method, Step width 0.01

**In-app purchases:** none


## Frequently asked questions

### Is Complex RPN Calculator free?

Complex RPN Calculator is free to download, with no in-app purchases.

### Is ODE Solver + free?

ODE Solver + is free to download, with no in-app purchases.

### Which has better reviews, Complex RPN Calculator or ODE Solver +?

ODE Solver + is rated higher. Complex RPN Calculator averages 3.9 out of 5 from 24 ratings, while ODE Solver + averages 4.0 from 4 ratings.

### Do Complex RPN Calculator or ODE Solver + have ads?

ODE Solver + shows ads; Complex RPN Calculator does not.

### Which is updated more often, Complex RPN Calculator or ODE Solver +?

Complex RPN Calculator ships an update every 5 months, and ODE Solver + weekly. Most recently, Complex RPN Calculator was updated on October 21, 2026 and ODE Solver + on October 24, 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.*