# RPN Calc vs TAGLOCK

The clearest difference is price: TAGLOCK at Free against RPN Calc's $0.99. TAGLOCK also leads on update cadence (every 9 days vs every 3 months) and iOS requirement (11.0 vs 16.0). On ads, in-app purchases and device support there is nothing between them.

TAGLOCK is free to download; RPN Calc costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

RPN Calc ships an update every 3 months, TAGLOCK every 9 days. The most recent releases landed on October 23, 2026 and October 19, 2026 respectively.

## The numbers

| Metric | RPN Calc | TAGLOCK |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | **[4.0 (6 ratings)](https://appshunter.io/ios/app/rpn-calc/id285002799/reviews)** | — |
| Number of ratings | **6** | — |
| Positive reviews | 37.9% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Every 9 days** |
| Monetization | Free | — |
| Size | 3 MB | 16 MB |
| Requires iOS | 16.0 | **11.0** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPod |
| Age rating | +4 | 4+ |
| Developer | [James Mattis](https://appshunter.io/developer/285002802) | [明 赖](https://appshunter.io/developer/1599063278) |

## What reviewers say

### RPN Calc

[App page](https://appshunter.io/ios/app/rpn-calc/id285002799)

This app provides a straightforward reverse Polish notation (RPN) calculator experience, inspired by classic HP models. It offers a clean interface with large buttons for quick calculations on iPhone, iPad, and Apple Watch, along with a convenient Today Extension for immediate access.

**Highlights:** Reverse Polish Notation (RPN) input, Clean, simple interface, Large, easy-to-press buttons, iPhone, iPad, and Apple Watch support, Today Extension for quick access

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


### TAGLOCK

[App page](https://appshunter.io/ios/app/taglock/id1634234036)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is RPN Calc free?

RPN Calc costs $0.99, with no in-app purchases.

### Is TAGLOCK free?

TAGLOCK is free to download, with no in-app purchases.

### Do RPN Calc or TAGLOCK have ads?

Neither RPN Calc nor TAGLOCK shows ads.

### Which is updated more often, RPN Calc or TAGLOCK?

RPN Calc ships an update every 3 months, and TAGLOCK every 9 days. Most recently, RPN Calc was updated on October 23, 2026 and TAGLOCK on October 19, 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.*