Only One Calculator vs Key Calculator
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. **
Key Calculator
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Revolutionary Tap-to-Calculate Select an operator (+−×÷) first, then tap numbers to instantly calculate results. Saves 3 steps vs traditional calculators! Customize Your Number Pad Adjust max/min values, set step increments, and save frequent numbers. Build your dream keypad for faster inputs. Undo Mistakes Instantly Typed a wrong number? Undo your last action with one tap—no restart needed. Calculation Time Machine Auto-saves every step. Tap any history entry to resume calculations right where you left off.
Screenshots
Verdict
Only One Calculator and Key Calculator are too close to call on the numbers: across 5 compared parameters — price, ads, in-app purchases and device support among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.
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.
| Parameter | Only One Calculator | Key Calculator |
|---|---|---|
| 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 | — |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 11.0 — better | 12.0 |
| Further details — not scored | ||
| Size | 34 MB | 27 MB |
| Age rating | 4+ | 4+ |
| Developer | Jia Hua Huang | 瑞勤 李 |
In-app purchases
Only One Calculator
No in-app purchases
Key Calculator
No in-app purchases
Questions
Is Only One Calculator free?
Is Key Calculator free?
Do Only One Calculator or Key Calculator have ads?
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