Guides
Reference material on the units behind each converter, written for when you need to understand why, not just get a number.
Aug 10, 2026
Why converting Celsius to Fahrenheit isn't just multiply-and-add
Most unit conversions are a single multiplier. Temperature needs an offset too, because Celsius and Fahrenheit don't share a zero point. The formulas, the common mistake, and why science uses Kelvin.
Aug 14, 2026
KB vs KiB vs MB: why your hard drive shows less space than advertised
Drive manufacturers count in decimal (1,000-based) units; your operating system counts in binary (1,024-based) units. Here's the actual math behind the missing gigabytes.
Aug 17, 2026
Metric vs. imperial: a practical conversion cheat sheet
The handful of conversions people actually look up constantly, plus a few memorable approximation tricks for doing them in your head.
Aug 20, 2026
PSI, bar, atm, pascal: converting pressure units without the confusion
Four common pressure units, four different fields that adopted them, and the reference-point conversions that connect all of them.
Aug 21, 2026
Why feet, inches, and miles are the sizes they are
Feet and inches started as body parts, the mile got fixed at a strange number of feet on purpose, and the meter has been redefined four times. The actual history behind the numbers.
Aug 23, 2026
Short ton, long ton, metric tonne: why 'a ton' means three different things
A US ton, a UK ton, and a metric tonne are all different weights, and the gap comes down to how a hundredweight got defined on each side of the Atlantic. Plus why gold is priced in troy ounces.
Aug 26, 2026
US gallons vs UK gallons: why they're not the same size
A UK gallon is about 20% bigger than a US gallon, and they've never matched. Here's the actual reason, plus why US and UK cups and fluid ounces are also different.
Aug 28, 2026
Where the acre came from, and why land is still measured in it
43,560 square feet isn't a random number. It comes from an old plowing measurement and a surveyor's chain, and it's why a square mile splits into exactly 640 acres.
Aug 30, 2026
Knots, mph, and why Mach 1 isn't a fixed speed
Why ships and planes measure speed in knots instead of mph, and why the speed of sound (Mach 1) is actually slower at cruising altitude than at the ground.
Sep 1, 2026
Why months don't have a fixed length (and time math is messier than it looks)
Calendar months range from 28 to 31 days, years need leap days to stay lined up with the seasons, and for decades we even added leap seconds. Here's why time doesn't divide evenly.
Sep 2, 2026
Calories, joules, and why your electric bill uses neither
Food labels, physics class, and your power company all measure energy, just in completely different units. Why the food Calorie is secretly 1,000 calories, and what a 'ton' of air conditioning actually means.