Tools · free conversion utilities

Convert between decimal numbers and Roman numerals · 1 through 3999, with additive and subtractive logic shown.

Live conversion between binary, decimal, hexadecimal, and octal · type in any field and the others update.

Convert any decimal to scientific or engineering notation · exponents in multiples of 3 for engineering style.

Three-way conversion · automatic GCD reduction, mixed-number support, percent display.

Add the outcomes of a bet · their chances and payoffs · and read the probability-weighted expected value and net gain live.

Convert times across cities · automatic DST handling, shareable links for cross-zone meetings.

Duration between two dates, add or subtract days, exclude weekends, presets for 7 / 30 / 90 / 100-day milestones.

Great-circle (Haversine) distance between any two latitude/longitude pairs · returns kilometres, miles, and the cardinal bearing.

Convert decimal degrees (DD) to degrees-minutes-seconds (DMS) · one-click open in Google Maps or OpenStreetMap.

Look up latitude and longitude from a city name · or paste coordinates and get the city back. Works fully offline against a built-in city table.

Live conversion between Celsius, Fahrenheit, Kelvin, and Rankine · with absolute zero and other reference points.

Volume conversion (tsp to gallon), US vs metric, ingredient weight approximations, recipe scaling 0.5x to 3x.

Measure your internet speed in practical terms · how many documents or photos you can transfer per minute, your streaming quality, and where you land on a capability ladder from dial-up era to fiber pro.