PrefixCalc vs Twin Calc

This calculator supports Metric‑prefix such as kilo and giga. The calculator supports quetta (10^30) and quecto (10^-30), which were added in 2022. Main Functions ・Support for arithmetic operations (+ - ×÷) ・Results converted to Japanese numerals for display ・Delete one character at a time with the "DEL" button 　Press and hold to delete all ・Press and hold to copy calculation formulas and results 　English (Short scale, Long scale) and 　Chinese numerals can also be selected. ・Calculations that include prefixes such as 2M+1k, 2M×1μ, etc. Note: ・Very large numbers that exceed 200 digits may be rounded off for display and calculation purposes. 　Please note this when precision is required. ・Short scale and Long scale are currently supported up to 10^198. ・Kanji notation is supported up to 10^72. 　If it is greater than the number, it will be displayed in Arabic numerals.

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).