Calta vs RedoCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Calta
This calculator app offers advanced features like equation display, calculation history, and redo/undo functionality for easier use. Customize backgrounds and button shapes, and perform tax calculations with adjustable rates. It supports up to 20 digits and respects order of operations.
- Equation display
- Calculation history
- Redo and Undo functions
- Customizable background
- Customizable button shape
- Tax calculation
- Order of operations support
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Caltaでは、履歴の再利用・RedoやUndoなど独自の機能を持っていますが、使い方は簡単でこれらの機能は電卓をより便利にしてくれます。 Caltaには四則演算に加え様々な優れた機能があります。 ・数式が表示される ・履歴リスト ・好きな背景に変更 ・ボタンの形状を変更 ・税計算ができる ・演算の優先順位を考慮:例)「1 - 2 × 3 = -5」 ・最大で20桁の有効桁数 ・数式のRedo, Undo 【履歴リスト】 「時計マークの履歴ボタン」を押すことで、過去の計算を閲覧することができます。それぞれの計算をタップすることで「数式の答え」をペーストできます。また、長押しすることで「数式のペースト」「名前の変更」ができます。 【背景の変更】 「歯車マークの設定ボタン」「背景を変更」からフォトライブラリの画像から好きな画像を選択することができます。また、一部分のみをくり抜くことができます。 【ボタンの形状を変更】 「歯車マークの設定ボタン」「ボタンの形状を四角にする」からボタンの形状を丸と四角に切り替えることができます 【税計算】 「税」ボタンを押すことで「税込」、長押しすることで「税抜」の計算ができます。また、設定から税率を8%と10%に切り替えられます。 【数式のRedo, Undo】 左右の矢印を押すことで、数式を一個前の状態に戻したり進めたりすることができます。
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.
Screenshots
Verdict
The clearest difference is iOS requirement: Calta at 11.0 against RedoCalc's 18.0. On price, update cadence, 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.
Both ship on a similar rhythm, roughly every 3 days. The most recent releases landed on June 4, 2026 and September 8, 2026 respectively.
| Parameter | Calta | RedoCalc |
|---|---|---|
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| Update frequency | Every 3 days | Every 3 days |
| Ads | Yes | Yes |
| In-app purchases | No | No |
| Monetization | Ad-supported | — |
| Devices | iPhone, iPod — better | iPhone |
| Requires iOS | 11.0 — better | 18.0 |
| Further details — not scored | ||
| Size | 23 MB | 3 MB |
| Age rating | 4+ | 4+ |
| Developer | Hiroki Oka | Toshiyuki Kuwabara |
In-app purchases
Calta
No in-app purchases
RedoCalc
No in-app purchases









