A calculator app maker lets you build the calculator you actually reach for: the buttons where your thumb expects them, a history you can reuse and the functions you need, nothing more. Describe it in plain words, the AI agent writes a real Android app, you tap through sums in the emulator preview and download the APK. It also makes a great first project if you are new to building apps.
What your calculator app will have
From the idea above, the agent builds:
- Keypad — large rounded buttons for digits, the four operations, percent, plus/minus, decimal point, backspace and clear.
- Two-line display — the full expression on top and a live result underneath that updates as you type.
- History — a panel that slides up with past calculations; tap one to put it back on the display.
- Scientific mode — sin, cos, tan, log, square root, powers, pi and brackets when you turn the phone sideways.
- Themes — dark and light, with a short vibration on each key press that you can turn off.
The calculator follows standard order of operations, so 2 + 3 × 4 gives 14, and it rounds tiny floating-point errors away for display.
Features you can ask for
- Memory keys (M+, M−, MR, MC) with the stored value shown on screen.
- Degrees and radians switch for the scientific functions.
- A tip and split-the-bill screen next to the keypad.
- Copy the result with a long press, and share the whole history.
- Thousands separators in the format you use, such as 1,234,567.89.
- A programmer mode with binary, octal and hexadecimal.
- Custom button colors, fonts and your own app icon.
Ideas to make it yours
For precise formulas, rounding rules and how to package several calculators into one app, read how to build a calculator or converter app. Building one for class? The school project guide explains how to present it.
Get it on your phone
- Press Build this calculator app and sign in with Google.
- Tap through a few sums in the emulator preview: a long chain, a percentage, a division by zero.
- Ask for changes in plain words: "move the equals button to the right", "make zero a wide key", "add a square root key to the main pad".
- Press Download APK and install it on your Android phone.
- For Google Play, build the signed APK and AAB from the same menu; the APK builder page explains signing and upload.
Decide how percent should behave before you build. On some calculators 200 + 10% gives 220, on others it gives 200.1. Say which one you want and the agent builds it that way.
Getting the math right
People trust a calculator completely, so small details matter. Test the edge cases on purpose: dividing by zero should show a clear message instead of a crash, very large numbers should switch to scientific notation neatly, and pressing equals twice should either repeat the last operation or do nothing, as you prefer. Ask for full precision inside the calculation and rounding only on the display. Check a few scientific results against a calculator you already trust. If anything is off, paste the case into the chat; the agent fixes the rule and keeps your example as a check for later changes.
Frequently asked
Will my calculator get the math right?
The agent follows standard order of operations and can explain every rule it used. Test a few sums you know the answer to; if one is off, paste the expected result into the chat and the agent fixes it.
Can I build a special-purpose calculator instead?
Yes. Describe the inputs and the formula in plain words, for example a tip splitter or a tile estimator, and the agent builds the screens and the calculation around them.
Does the calculator app need internet?
No. Everything runs on the phone, including history, so it opens instantly and works anywhere.
How do I install my calculator on Android?
Press Download APK in the builder, open the file on your phone and allow installs from your browser once. It then sits on your home screen like any other app.
Make your calculator app now — free to start
Describe it, sign in, and the agent builds it while you watch. Change anything by asking.
Build this calculator app ›