Permutation and Combination Calculator (nPr, nCr)
The more options there are for messing something up, even a seemingly simple one, the more panicky it gets. You’re standing in line at the … Read More
JSCalc
Sample Size Power Calculator for Effect Size & Power
Your goal is to plan a study and wonder about its validity. It is not merely about collecting data, but about whether you’ll have enough … Read More
Torque Wrench Extension Calculator (Crowfoot Setting)
I’ve always tightened a lug nut with a wrench, and when it clicks I think I’m at the right spec, but using an adapter can … Read More
Area Converter: sq m, sq ft, Acre, Hectare, sq mile
It’s one of those concepts that’s difficult to wrap your head around: area is not linear but exponential. Double the size of a square and … Read More
Impact Force Calculator: Fall & Collision Force (N, g)
Drop your smart phone, which lands on tile. You feel your stomach drop before you even look. Your stomach drops as you hear a crack. … Read More
Length Converter: mm, cm, m, km, in, ft, yd, Miles
How do you measure distances? Yeah, that’s easy, right up until the day you live in a country that uses feet instead of meters and … Read More
Pipe Velocity Calculator: Flow Rate to Fluid Speed (V=Q/A)
If you flip on a faucet and hear a distinctive whining sound through the walls, then you’re also hearing what’s happening: Water is flowing at … Read More
Coulomb Force Calculator: Solve F, Charge, or Distance
The force between two atoms is immense. Yet the static shock you feel when touching a doorknob is tiny compared to it. But that tiny … Read More
Caffeine Half Life Calculator: Decay, Bedtime & Sleep
It’s time to hit the hay, but as you lie down, your blood continues to pump with caffeine. How long until it clears out? Use … Read More
Tire Size to Gear Ratio Calculator: Regear for Bigger Tires
Big tires are a good idea; right? Well that depends. If you want more “power” in your vehicle (i.e., better gas mileage or more off-road … Read More