Hissab - Natural-Language Calculator

Strict, unit-aware calculator for units, dates, percentages, finance and developer math, with inline results and graphs.

Hissab is a calculator you write in like a notepad. Put one calculation on each line, in plain words, and the answer appears on the right as you type. 5 km to miles → 3.1069 miles 20% of 150 → 30 3:30 pm pst in london → 11:30 pm london emi(360000, 6.5%, 30 years) → 2,275.4449 255 to hex → 0xff What it can do • Units: length, weight, volume, temperature, speed, area, data, energy, pressure and more, including compound units such as km per hour. If the units don't match, you get an error instead of a wrong answer. • Dates and times: add durations to dates, measure the time between two dates, convert times across time zones, and turn Unix timestamps into readable dates. • Percentages and money: percent of, discounts, sales tax, tips, loan EMIs, simple and compound interest, CAGR, NPV and IRR. • Developer math: hex, binary and octal, bitwise operators, IPv4 and IPv6 addresses and subnets, colors, hashes (MD5, SHA-1, SHA-256, SHA-3, CRC32 and more), UUIDs and random IDs. • Math and science: trigonometry, logarithms, statistics, combinatorics, complex numbers, matrices, symbolic algebra, and derivatives and integrals shown in proper math notation. • Graphs: draw(sin(x), cos(x)) plots curves right under your calculations. Works like a scratchpad • Name a value once (price = 1299) and use it on any later line. • Refer to earlier results with prev, or by line number (line3). • Double-click a result to copy it. • Click a color or a date to change it with a picker. • Your sheet saves automatically and is waiting the next time you open the popup. Private by design • No account and no sign-in. • No permissions: Hissab can't see or change the pages you visit. • No analytics or tracking. Your calculations stay on your device. • Works offline. Upgrading from Hissab 3.x? The calculations from your last notebook are brought over the first time you open the new popup. More from Hissab The full notebook app, with multiple notebooks and optional AI features, is free at https://hissab.io. There is also a command-line tool and an npm library for developers, and a skill that lets AI agents hand their math to Hissab. Hissab is open source under the MIT license: https://github.com/rawbytess/hissab