123 Calculator: Reverse Keypad

123 Calculator is a focused calculator with a phone-style keypad: 1, 2, and 3 start on top. Tap 1 ⇄ 7 to switch instantly between phone order and traditional calculator order. It includes four-function arithmetic, percentages, decimals, repeated equals, adaptive number display, haptic feedback, and VoiceOver labels. Calculations run locally on your iPhone. No account, network connection, ads, tracking, or permissions required.