Global Time Machine vs RPNu
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Global Time Machine
Easily track the time in any city worldwide. Add locations to your list to plan international calls, meetings, or connect with loved ones abroad. Features DST support and quick access to nearby hours.
- Track time in over 20,000 cities
- View nearby hours by scrolling
- Convenient world clock interface
- DST support for all locations
- Shake to reset functionality
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Global Time Machine shows every time zone you care about on one line. Add your cities, drag any scale and watch them all move together. Made for iPhone Duo: cities and your calendar side by side when open, a desk clock when half-folded. • World clock for 34,000+ cities — search in any language, works offline • Drag to travel in time: plan calls and meetings across time zones • Day and night at a glance: cities where it is night turn dark • Your own place is detected automatically, wherever you travel • Your calendar on the time line — see when you are busy • Half-hour and 45-minute offsets and daylight saving time, always correct • Shake to jump back to now • 12- or 24-hour clock, light and dark themes, 19 languages • Lists (Premium): Separate sets for team, family and friends • Invite a friend: See their local time and when they are busy Free plan: your place and two cities; one friend Premium: Unlimited cities, Lists, Unlimited friends, Find friends in contacts 14-day free trial, then a monthly or yearly subscription. Payment is charged to your Apple ID account. The subscription renews automatically unless it is cancelled at least 24 hours before the end of the current period. You can manage or cancel it in your App Store account settings. Terms of Service: https://thetimemachine.global/terms
RPNu
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RPNu is a calculator that makes crunching numbers easier than it’s algebraic equivalent. RPN stand for Reverse Polish Notation (The ‘u’ stands for universal, meaning it runs on both the iPad and iPhone.) and is the numeric evaluation method used for this app. RPN, I feel, is far superior to the algebraic method and once learned you will never want to use the algebraic again. This calculator has all the normal mathematical function, but also contains a host of other functions that you may find very useful. Space is limited in this description but here are the highlights: Help: There is extensive help to aid the user in determining how to use this app. It is also context sensitive. Programable: You can write your own programs and there are many tools to aid you in doing this. Graphics: You can graph equations and there are several modes to cover almost all requirements. A universal converter that you will find very useful. Matrix arithmetic (determinate, invert, add, subtract and multiply). Date calculator and an hours calculator with moon phase display. Elements and periodic table information. Combinations and permutations calculator Equation integration and root finder. Amortization with many useful functions. Mapping function that allows you to determine distance between points and other functions. Hyperbolic functions. Hexadecimal, Octal, and Binary modes. Barometer function showing QNE and QNH. A compass that not only shows magnetic and true north, but also shows the address you are at. This app includes extensive support for a Bluetooth keyboard. Also, extensive support is given to export your calculations to either email or the universal clipboard.
Screenshots
Verdict
The clearest difference is update cadence: Global Time Machine at every 5 days against RPNu's every 2 months. RPNu's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.0). On price, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Global Time Machine ships an update every 5 days, RPNu every 2 months. The most recent releases landed on October 24, 2026 and October 12, 2026 respectively.
| Parameter | Global Time Machine | RPNu |
|---|---|---|
| Price | Free | Free |
| Rating | 3.7 (7 ratings) — better | — |
| Positive reviews | 58.3% of reviews | — |
| Number of ratings | 7 — better | — |
| Update frequency | Every 5 days — better | Every 2 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone | iPhone, iPad, iPod — better |
| Requires iOS | 17.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 10 MB | 49 MB |
| Age rating | 4+ | 4+ |
| Developer | theMakeApp | Scott Johnson |
In-app purchases
Global Time Machine
No in-app purchases
RPNu
No in-app purchases









