Comparison

Only One Calculator vs Key Calculator

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

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.

Highlights
  • Instant currency exchange
  • Unit conversion (length, weight, area, volume, temperature)
  • Undo/Redo functionality
  • History of calculations
  • Customizable keyboard layout
  • Real-time calculation results
Read full description

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. **

About

Key Calculator

Features
Read full description

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

Only One Calculator4 screens
Key Calculator4 screens

Verdict

The call

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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ScorecardNo meaningful differences
Only One Calculator versus Key Calculator: the parameters behind the verdict, then further details
ParameterOnly One CalculatorKey Calculator
PriceFreeFree
Rating5.0 (2 ratings) — better—
Positive reviews100.0% of reviews—
Number of ratings2 — better—
Update frequencyEvery 2 weeks—
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS11.0 — better12.0
Further details — not scored
Size34 MB27 MB
Age rating4+4+
DeveloperJia Hua Huang瑞勤 李

In-app purchases

None

Only One Calculator

No in-app purchases

None

Key Calculator

No in-app purchases

Questions

Is Only One Calculator free?
Only One Calculator is free to download, with no in-app purchases.
Is Key Calculator free?
Key Calculator is free to download, with no in-app purchases.
Do Only One Calculator or Key Calculator have ads?
Neither Only One Calculator nor Key Calculator shows ads.

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