RedoCalc vs Stopwatch Library
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
RedoCalc
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This is a calculator for people who only use it for simple calculations, such as adding up receipts or calculating the cost of a meal split between several people, but who are always worried about whether the input was correct. As it is a simple calculator, the only operations it can perform are - Four arithmetic operations (addition, subtraction, multiplication, division) - Percentage calculations (including calculations such as consumption tax using percentages) . The results are displayed as numbers with a digit symbol. There is no complicated exponential display. The calculation proceeds in the order of the keys you enter. There is no priority for multiplication or division. The formulas you enter are displayed in order in the upper area as a history. If you tap the white part, it will turn yellow and you will be able to modify that part. (You can modify not only numbers, but also arithmetic symbols such as + and ×.) If you tap “=”, the expressions from the first line to the last line will be recalculated. The result will be automatically copied, so you can switch to other apps and paste the value there.
Stopwatch Library
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複数のストップウォッチを表示させることができます。 アナログかデジタルかは選んでください。
Screenshots
Verdict
The clearest difference is in-app purchases: RedoCalc at none against Stopwatch Library's 1. Stopwatch Library's advantage is ads (none vs shown). On price, update cadence, device support and iOS requirement 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. Stopwatch Library sells 1 one-off in-app purchase. RedoCalc asks for nothing beyond the download.
Both ship on a similar rhythm, roughly every 3 days. The most recent releases landed on September 25, 2026 and September 28, 2026 respectively.
| Parameter | RedoCalc | Stopwatch Library |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 3 days | Every 3 days |
| Ads | Yes | No — better |
| In-app purchases | No — better | Yes |
| Devices | iPhone | iPhone, iPad — better |
| Requires iOS | 18.0 | 17.0 — better |
| Further details — not scored | ||
| Size | 3 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | Toshiyuki Kuwabara | Naoyuki Hasegawa |
In-app purchases
RedoCalc
No in-app purchases
Stopwatch Library
- 広告を削除$2.99
Questions
Is RedoCalc free?
Is Stopwatch Library free?
Do RedoCalc or Stopwatch Library have ads?
Which is updated more often, RedoCalc or Stopwatch Library?
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