# MathU RPN Calc vs Qualifier Plus IIIx/fx

The clearest difference is price: Qualifier Plus IIIx/fx at Free against MathU RPN Calc's $24.99. Qualifier Plus IIIx/fx also leads on ratings volume (3.5K vs 149). MathU RPN Calc's advantage is in-app purchases (none vs 2) and update cadence (every 6 weeks vs every 10 months). On rating, review sentiment, ads and chart position there is nothing between them.

Qualifier Plus IIIx/fx is free to download; MathU RPN Calc costs $24.99 up front. Qualifier Plus IIIx/fx sells 2 in-app purchases, starting at $5.99 per month. MathU RPN Calc asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for MathU RPN Calc against 4.9 for Qualifier Plus IIIx/fx. That said, the two scores are not equally well evidenced: Qualifier Plus IIIx/fx has 3.5K ratings behind it against 149, so its average is the more settled of the two. Written reviews are what separate them: 93% of MathU RPN Calc's written reviews are positive against 89% of Qualifier Plus IIIx/fx's.

MathU RPN Calc ships an update every 6 weeks, Qualifier Plus IIIx/fx every 10 months. Both last shipped on October 29, 2026.

## The numbers

| Metric | MathU RPN Calc | Qualifier Plus IIIx/fx |
| --- | --- | --- |
| Price | $24.99 | **Free** |
| Rating | **[5.0 (149 ratings)](https://appshunter.io/ios/app/mathu-rpn-calc/id293653078/reviews)** | [4.9 (3.5K ratings)](https://appshunter.io/ios/app/qualifier-plus-iiixfx/id398253583/reviews) |
| Number of ratings | 149 | **3.5K** |
| Positive reviews | **92.5% of reviews** | 89.2% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 6 weeks** | Every 10 months |
| Monetization | **Paid** | Subscription |
| Best chart rank | #152 | **#135** |
| Size | 8 MB | 28 MB |
| Requires iOS | 16.6 | **15.0** |
| Devices | iPhone, iPad, Mac | iPhone, iPad, iPod |
| Age rating | 4+ | 12+ |
| Developer | [Creative Creek, LLC](https://appshunter.io/developer/293653081) | [Calculated Industries](https://appshunter.io/developer/370406449) |

## What reviewers say

### MathU RPN Calc

[App page](https://appshunter.io/ios/app/mathu-rpn-calc/id293653078)

**Currently charting:** #152 Top Paid · Finance (US App Store)

This advanced scientific and financial calculator utilizes the Reverse Polish Notation (RPN) system. It offers over 96 functions, catering to professionals with features for finance, programming, and general scientific calculations. Optimized for iOS devices, it provides a robust and accurate computational experience.

**Highlights:** RPN entry system, Over 96 functions, Scientific calculations, Financial calculations (IRR, NPV, mortgage), Programmer's calculator (HEX, OCT, DEC, BIN), IEEE double precision accuracy, Portrait/landscape keypad switching

**Features:** Vision Pro support

**In-app purchases:** none


### Qualifier Plus IIIx/fx

[App page](https://appshunter.io/ios/app/qualifier-plus-iiixfx/id398253583)

**Currently charting:** #135 Top Grossing · Finance (US App Store)

This app provides advanced real estate and mortgage finance calculations for professionals. It offers instant solutions for loan payments, buyer qualifying, cash flow analysis, and more, directly on your mobile device.

**Highlights:** Instant loan payment calculations (P&I, PITI), Buyer qualifying for conventional, FHA, and VA loans, Complete cash flow solutions (IRR, NPV, NFV), Amortization schedules with remaining balances, Bi-weekly loans and ARMS calculations, Rent vs. Buy comparisons, Date Math function

**Features:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 1 Month Full Access | $5.99 | per month |
| 1 Year Full Access | $29.99 | per year |

**What reviewers like**

- 🚀 Convenient and portable
- 👍 Powerful and feature-rich
- 💡 Helpful for real estate professionals
- 👍 Familiar interface for existing users
- 💡 Email integration for sharing calculations

**What reviewers complain about**

- 💰 Subscription model is frustrating
- 🐛 Occasional bugs and glitches
- 💰 Perceived as greedy by developers
- 🔒 Requires in-app purchase to use

**Reported bugs**

- Numbers not saving or changing
- Compatibility issues with newer devices

**Requested features**

- Dark mode option
- Basic free version
- Improved user guide and documentation


## Frequently asked questions

### Is MathU RPN Calc free?

MathU RPN Calc costs $24.99, with no in-app purchases.

### Is Qualifier Plus IIIx/fx free?

Qualifier Plus IIIx/fx is free to download, with in-app purchases available.

### Which has better reviews, MathU RPN Calc or Qualifier Plus IIIx/fx?

MathU RPN Calc is rated higher. MathU RPN Calc averages 5.0 out of 5 from 149 ratings, while Qualifier Plus IIIx/fx averages 4.9 from 3.5K ratings.

### Do MathU RPN Calc or Qualifier Plus IIIx/fx have ads?

Neither MathU RPN Calc nor Qualifier Plus IIIx/fx shows ads.

### Which is updated more often, MathU RPN Calc or Qualifier Plus IIIx/fx?

MathU RPN Calc ships an update every 6 weeks, and Qualifier Plus IIIx/fx every 10 months. Most recently, MathU RPN Calc was updated on October 29, 2026 and Qualifier Plus IIIx/fx on October 29, 2026.

### Which is more popular, MathU RPN Calc or Qualifier Plus IIIx/fx?

MathU RPN Calc currently peaks at #152 in the App Store charts, and Qualifier Plus IIIx/fx at #135. Chart position reflects recent download velocity rather than total install base.

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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.*