Twin Calc: Two Calculators

Twin Calc puts two independent calculators on one screen — a simple calculator app for anyone who has ever wished they had two.

Compare two estimates. Split a bill two different ways. Convert on one side while you total on the other. Check last year's numbers against this year's. Open Twin Calc and calculators A and B are already there — no onboarding, no sign-up.

Features
- Calculator A and B stacked vertically (or side by side in landscape), each fully independent
- Works just like the built-in iPhone calculator: + − × ÷, %, ±, backspace, and thousands separators
- An expression line shows what you are calculating, so you never lose track
- Drag the divider to resize the two calculators; double-tap to reset to half and half
- Long-press a result to copy it; swipe left to delete one character
- Haptic feedback (can be turned off)
- History (tape) keeps your results automatically — tap to copy, or send a result back to A or B
- Light and dark themes that follow your system setting
- Both calculators and the split ratio are restored exactly as you left them

Free
- Two calculators, history, and reuse of your 3 most recent results
- No ads

PRO (one-time purchase)
- Never retype a result again: send A's answer straight to B, or swap A and B in one tap
- Bring back any past result from history
- 3 extra themes: Midnight, Paper, and Mono

PRO is a single one-time purchase. No subscription, no extra fees.

Everything you calculate stays on your device and is never sent to a server.

For iPhone (portrait and landscape).