シンプル電卓-履歴付き計算機

Simple Calculator is an app that strips away unnecessary features from a standard calculator.

For things like totaling purchases, splitting bills, managing household finances, and calculating prices including tax, simple calculations suffice for 90% of calculator use.

Many calculator apps have buttons for trigonometry and logarithms, but since those functions aren't necessary for everyday calculations, we've limited the features.

■ A calculator that shows "what you're calculating right now"
Ordinary calculators only show the answer.

Have you ever had the experience of forgetting whether you subtracted or added 1,500 and having to start over?

With Simple Calculator, the moment you press an operator like + or ×, the previous expression is recorded on the screen.

If you enter 100 + 200 and press ÷, "100 + 200 = 300" will appear on the screen. If you then enter ÷6, "300 ÷ 6 = 50" will be added below.

While using the calculator, the calculation process is recorded just like a notebook.

Even when performing multiple steps, such as totaling, dividing by the number of people, and rounding up the remainder, all intermediate results are visible, so you don't have to go back and think, "Wait, what was the total again?"

■ History up to 100 entries, and you can write notes
The upper half of the screen is the history area. Calculation results are stacked from bottom to top. Tapping allows you to reuse the result in the next calculation, and long-pressing lets you write notes.

Leaving notes such as "March food expenses," "apartment management fees," or "reimbursement for drinking party" prevents you from wondering "What was this calculation for?" when reviewing later.

This is convenient for when you want to make a note but don't want to open a full budgeting app.

The history is retained up to 100 entries, and older entries are automatically deleted. It remains even when the app is closed, so you can continue later.

■ Make everyday percentage calculations intuitive
Percentage calculations can be confusing because different calculators behave differently. This simple calculator is designed to match your intuition.

Entering 1,000 + 10% gives you 1,100 (tax-inclusive calculation).

5,000 − 30% gives you 3,500 (30% off sale price).

1,000 × 10% gives you 100 (amount equivalent to 10% of 1,000).

Everyday percentage calculations such as tax-inclusive, tax-exclusive, discounts, and percentages can be entered directly without any additional operations.

■ Designed to minimize calculation errors
General calculator apps can sometimes have slight errors due to the limitations of floating-point arithmetic within computers, such as "0.1 + 0.2" becoming "0.30000000000000004". This is problematic behavior for people who are concerned about even a 1-yen discrepancy in their household budget.

Simple Calculator uses high-precision calculation (BigDecimal) to minimize errors in basic arithmetic operations. It can be used with confidence in situations where accuracy is crucial, such as expense reports, calculating tax-inclusive prices, and providing estimates.

■ User-Friendly Design for Error Prevention
AC (All Clear) resets only the current calculation; the history remains intact. This prevents accidental deletion of the entire history.

BK (Backspace) deletes only the previous character. Common mistakes like typing 10,000 instead of 1,000 can be corrected with a single tap without having to start over.

Tapping each entry in the history allows you to resume calculations from that point.

■ Uses:
* Checking totals and tax-inclusive prices while shopping
* Splitting bills and calculating tips at parties and lunches
* Monthly household budget summaries (food, utilities, communication expenses)
* Totaling expenses and receipts
* Rough estimates and unit price calculations for work
* Currency conversion while traveling
* Calculating quantities when scaling recipes by 1.5x or 0.5x

■ Features We Deliberately Didn't Include
We haven't included scientific calculator functions such as sin/cos/tan, logarithms, square roots, and parentheses. These are rarely used in everyday situations, and adding more functions would make the keys smaller, making it difficult to use while shopping or dining.

We decided that it's better to have separate tools for everyday use and for science/engineering tasks, as each is easier to use in its own way.

■ Design Details
The screen uses a consistent dark tone. We aimed for a color scheme that is easy on the eyes in both bright and dark environments. The font is Inter, a typeface that allows for clear and easy reading of numbers. Animations are kept to a minimum to avoid disrupting the calculation pace.

■ Data Saving and Restoration
Calculation history is saved on your device. It supports Android's automatic backup, so even if you change devices, you can restore your past history by reinstalling with the same Google account. There's no need to manually copy anything.

■ Part of the Simple Series
Simple Calculator is part of Morphyca's Simple Series. We will be sequentially releasing Android apps that focus on a single function, such as ad blockers, volume control, alarms, focus lock, and notes. The series is characterized by its minimalist design and the minimum necessary permission requests.

■ Privacy Considerations
Simple Calculator does not collect any personal information from users.

All calculation history and notes are saved on your device and are not sent to our or third-party servers. We do not collect names, email addresses, phone numbers, or location information. No account registration or login is required; you can use it immediately after installation.

For more details, please see our Privacy Policy: https://morphyca.com/products/simple-calc/privacy/

■ About Ads and Ad Removal
Simple Calculator is free. A small banner ad will appear at the bottom, but it is placed in a location that does not interfere with calculations. If you wish to remove ads, you can do so with a one-time purchase from the settings screen (no additional charges). Once purchased, the ad-free state will be automatically restored even if you reinstall on a different device.

■ Contact Us
If you encounter any problems or find the app difficult to use, please report them through "Report a Problem" in the settings screen.