Only One Calculator vs Conv3rtify
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Only One Calculator
This utility app offers instant currency exchange and unit conversions, making it ideal for travel and shopping. It features undo/redo functionality for easy editing and supports over 160 currencies with customizable update frequencies. Users can also access calculation history and customize the keyboard.
- Instant currency exchange
- Unit conversion (length, weight, area, volume, temperature)
- Undo/Redo functionality
- History of calculations
- Customizable keyboard layout
- Real-time calculation results
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This calculator has instant currency exchange and unit conversion. With the "Undo" and "Redo" functions, you can go back to the previous steps and edit it. Select a specified currency exchange to be fixed to the calculator. When you input a number or expression, you can instantly know the conversion result, which is convenient for traveling and shopping. Features: • Can select a specified currency exchange and pin it to the calculator. During the input process, you can instantly know the exchange result, which is convenient for travel and shopping. • With the "Undo" and "Redo" functions, the calculator allows you to go back to the previous steps. It keeps up to 300 input steps for your review. So you don't have to worry about re-entering because of any mistakes during input. • Can choose between more than 160 currencies, and the exchange rate is updated manually or automatically per hour, day, or week. • The calculation expression and calculation result are recorded when pressing the equal button or clear button. You can insert the calculation expression or calculation result from a history record into the current calculation expression. • Can edit a very long calculation, and cursor control is very convenient and smooth. • During the input process, the calculation result will be shown instantly without pressing the equal button. • In addition to currency exchange, there are other conversion functions for length, weight, area, volume, and temperature. • If you need the Memory Buttons on traditional calculators, you can add them into the keyboard layout. ** Note: No Scientific Calculation Function. Not suitable for users who need Scientific Calulation. **
Conv3rtify
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Conv3rtify is a powerful universal unit conversion tool that will make your life easier. In the app you'll find 3 main sections: - Standard, with some basic units (length, area, volume, mass, angle, time, etc.) - Pro, with more advanced and specific ones (colors, currency, base, and temperature conversion systems) - Favorites, where you can save the units you use the most — Pro features are available only with the Conv3rtify+ program. Upgrade to Conv3rtify+ to remove ads & unlock all the powerful capabilities of the app. It's a 1-time paying program: you pay once and you're able to use your app at 100% forever. When our team will come up with new cool features, you'll simply need to enjoy them and you won't be obliged to pay another time. — Conv3rtify also allows users to choose between 2 different themes: light and dark mode. There is even the possibility to select an automatic mode that will change the app's theme based on the device's theme.
Screenshots
Verdict
The clearest difference is in-app purchases: Only One Calculator at none against Conv3rtify's 1. Only One Calculator also leads on update cadence (every 2 weeks vs every 26 months) and iOS requirement (11.0 vs 15.1). On price, ads and device support 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. Conv3rtify sells 1 one-off in-app purchase. Only One Calculator asks for nothing beyond the download.
Only One Calculator ships an update every 2 weeks, Conv3rtify every 26 months. The most recent releases landed on November 3, 2026 and November 7, 2026 respectively.
| Parameter | Only One Calculator | Conv3rtify |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (2 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 2 — better | — |
| Update frequency | Every 2 weeks — better | Every 26 months |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 11.0 — better | 15.1 |
| Further details — not scored | ||
| Size | 34 MB | 40 MB |
| Age rating | 4+ | 4+ |
| Developer | Jia Hua Huang | Ilya Emeliyanov |
In-app purchases
Only One Calculator
No in-app purchases
Conv3rtify
- Conv3rtify+$2.99
Questions
Is Only One Calculator free?
Is Conv3rtify free?
Do Only One Calculator or Conv3rtify have ads?
Which is updated more often, Only One Calculator or Conv3rtify?
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