General & engineering
Basic and scientific tools, cars and 3D printing.
General tools
Dice Roller
Roll anything, and see how likely the number you just got actually was.
Random Number Generator
Pick numbers in a range — with or without repeats.
Basic Calculator
The plain four-function calculator — plus what your answer looks like in other forms.
Scientific Calculator
Type a whole expression. Trig, logs, powers, roots and factorials.
3D Printing & Maker
Filament Weight Calculator
Filament weight and length calculator for 3D printing. Grams to metres by material density, for 1.75, 2.85 and 3.00 mm filament.
Filament Remaining Calculator
Filament remaining calculator. Length and weight left on a partly used spool from outer diameter, core diameter and winding width.
Steps Per mm Calculator
Steps per mm calculator for 3D printers and CNC. Belt-driven and leadscrew axes from motor steps, microstepping, pulley teeth and screw pitch.
Belt Length Calculator
Timing belt length calculator. Closed loop length and tooth count from pulley teeth and centre distance, for GT2, GT3 and HTD belts.
Layer Height Calculator
Layer height calculator for 3D printing. Finds the magic numbers that divide evenly into the Z axis full-step distance.
Extrusion Multiplier Calculator
Extrusion multiplier and flow rate calculator. Corrects flow from a measured single-wall thickness against the expected extrusion width.
Print Scale Calculator
Print dimensional accuracy calculator. Scale percentage and corrected steps per mm from a measured versus intended dimension.
Tap Drill Size Calculator
Tap drill and clearance hole size calculator for metric and UNC threads, with the formula and ISO 273 clearance sizes.
Automotive
Tire Size Calculator
Tire size comparison calculator. Overall diameter, circumference, revolutions per mile and speedometer error between two tire sizes.
Gear Ratio Calculator
Gear ratio calculator. Engine RPM from road speed, axle ratio, transmission ratio and tire diameter, or road speed from RPM.
Axle Ratio Calculator
Axle ratio calculator for a tire size change. Finds the new gear ratio that restores the original engine rpm at road speed.
Engine Displacement Calculator
Engine displacement calculator from bore, stroke and cylinder count. Results in cc, litres and cubic inches, with overbore comparison.
Compression Ratio Calculator
Compression ratio calculator from bore, stroke, chamber volume, gasket thickness, piston dish and deck clearance.
Wheel Offset Calculator
Wheel offset and backspacing calculator. Converts between the two and shows inboard and outboard movement against your current wheel.
Torque and Horsepower Calculator
Torque and horsepower calculator. Converts between hp, lb-ft and rpm, with metric kW and Nm equivalents.
Fuel Cost Calculator
Fuel cost calculator. Trip cost from distance, fuel economy and price, with MPG, L/100km and km/L conversions.