The RPN calculators you trust, rebuilt key for key.
Financial, scientific and programmer models for iPhone, iPad and Android. Every result is worked out in decimal, digit for digit, the way the originals do it.
One purchase unlocks all six calculators. No ads, no account, no tracking.
This keypad works. Try ·1 ENTER ·2 + ·3 − and see it land on exactly zero.
Why Calctro
An RPN calculator earns its place on your desk by being right every time and behaving the same way every time. Calctro is built to that standard.
Exact decimal maths
Most calculator apps work in binary floating point, where 0.1 + 0.2 − 0.3 comes out as a tiny leftover instead of zero. Calctro works in base ten, with ten-digit results rounded exactly as the originals round them, so money adds up to the cent and every last digit matches the hardware.
Every key, every message
All the gold and blue shifted functions, stack lift, LAST X, program editing and every error code behave as they do on the hardware. We test against the original owner's handbooks and real calculators on our bench, problem by worked problem.
Memory that never forgets
Continuous Memory keeps your stack, registers, cash flows and programs exactly as you left them, through app switches, restarts and updates. Each calculator keeps its own memory.
- Six calculators, one purchase. Two financial, three scientific and one programmer model, with new features arriving as free updates.
- Made for your device. The classic landscape face, a portrait layout with close to full-size keys, true-size faces on iPad, and foldable layouts that keep keys clear of the crease.
- Nothing to sign up for. No ads, no subscription, no account. Calctro collects no data at all.
- Works anywhere. Everything runs on your device, so it works on a plane, in an exam hall or in a basement server room.
Six calculators
Switch between them from the menu beside the face. Each one has its own keyboard, functions and memory.
FIN 12
The financial standard: time value of money, cash flows with NPV and IRR, amortisation, bonds, depreciation and date arithmetic.
FIN 12 P
Everything in FIN 12, plus algebraic entry with parentheses, undo, x² and 400 program lines.
SCI 15
The advanced scientific: complex numbers, matrices, SOLVE and numerical integration, with expanded memory.
SCI 11
A programmable scientific with hyperbolics, statistics and regression, labels, subroutines and indirect addressing.
SCI 10
The essential scientific: trigonometry, logs, polar and rectangular conversion, statistics and simple programs.
PRG 16
For programmers: hex, decimal, octal and binary; word sizes from 1 to 64 bits; shifts, rotates, masks and bit tests.
On your phone, tablet or foldable
Pre-release renders. Store screenshots will follow at launch.
Get Calctro
One price for all six calculators on iPhone, iPad and Android, with free updates.