Conversions calculators
Free unit converters: km to miles, km/h to mph, knots to mph, kg to lbs, ounces to pounds, grams to pounds, cm to feet and inches, ounces in a gallon, square feet to acres, inches to cm, meters to feet, feet to inches, liters to gallons, cups to mL, ounces to grams, decimal feet to feet and inches, fuel economy and trip cost, HEX/RGB/CMYK colors, molar concentration units, Celsius to Fahrenheit, millimeters to inches, mL to oz, stone to pounds, military time, Julian dates, water column to psi and battery mAh to Wh — each with charts.
Decimal Feet to Feet and Inches Converter
Convert decimal feet to feet and inches, or reverse the calculation. Enter fractions, choose rounding precision and copy the measurement.
Fuel Economy Calculator: MPG, L/100 km & Trip Cost
Convert mpg to L/100 km (235.215 ÷ US mpg, 282.481 ÷ UK mpg), L/100 km to mpg and km/L, with full charts. Calculate real fuel economy from refills and trip cost.
Color Converter: HEX, RGB & CMYK
Convert HEX and RGB exactly, preview approximate CMYK colors, copy CSS values and convert a batch of HEX colors. Includes formulas and limitations.
Molarity Unit Converter (M, mM, µM, nM)
Convert mM to molar, µM, nM and pM, plus mg/mL to molarity with molar mass and normality to molarity. Full chart and worked examples.
Celsius to Fahrenheit Converter
Centigrade to Fahrenheit: °F = °C × 1.8 + 32. 30 °C = 86 °F, 40 °C = 104 °F. Convert °C, °F, K and °R, with a −40 to 100 °C table and weather points.
Millimeters to Inches Converter
Convert mm to inches with the exact 25.4 mm per inch: 1 mm, 1.5 mm, 2 mm and 0.05 mm answers, nearest 1/16–1/64 fractions, a ruler view and a 0.05–1,000 mm chart.
Military Time Converter (24-Hour Clock)
Convert military time to standard time and back — 1330, 1845, 2230 and every hour — with a full 24-hour military time chart and how to say it.
mL to oz Converter (750 mL in Ounces)
Milliliters to ounces: divide mL by 29.574. 5 mL = 0.169 oz, 750 mL = 25.36 oz. US or UK fl oz, cups, shots and a chart of bottle sizes.
Stone to Pounds Converter (st, lb, kg)
Convert kilos to stones and pounds, stone to lbs and kg. 1 stone = 6.35 kg = 14 lb. Kg to stone chart from 40 to 200 kg, plus 1–30 stone in pounds.
Water Column to PSI Converter (inWC, ftH₂O)
Convert inches or feet of water column (inWC, ftH₂O) to psi, kPa, mbar and back — for gas pressure, pumps, HVAC and water tanks.
mAh to Wh Converter (Battery Capacity)
Convert battery capacity between mAh, Ah and Wh at any voltage. Check power banks against the 100 Wh airline carry-on limit and estimate runtime.
Trash Bag & Bin Size Converter (Litres to Gallons)
Convert trash bag and wheelie bin sizes between litres and gallons: 13, 30, 33 and 55 gallon bags and 140–1,100 litre bins, and find the bag that fits.
Julian Date Converter (Day of Year & JD)
Convert a calendar date to Julian date: day-of-year codes (YYDDD) for packaging and military, astronomical JD and MJD, and back, with a day-of-year calendar.
Km to Miles Converter (Kilometers to Miles)
Convert km to miles (1 km = 0.621371 mi) and miles to km. 50 km = 31.07 mi, 20 km = 12.43 mi. Full chart, race distances (5K–marathon) and pace.
Km/h to MPH Converter
Convert km/h to mph and mph to km/h with the exact mile. Speed chart from 10 to 300 km/h, common speed limits, knots and meters per second.
Kg to Lbs Converter (Kilograms to Pounds)
Convert kilograms to pounds and pounds to kg with the exact 0.45359237 kg per lb. Get pounds and ounces, stone, and a full conversion chart.
Inches to Centimeters Converter
Convert inches to cm (1 in = 2.54 cm exactly) and cm to inches. Enter fractions like 3/4 or 1 3/8, see a ruler view and a chart from 1 to 100.
Meters to Feet Converter (Height in Feet & Inches)
Convert meters to feet and inches, e.g. 1.6 m to 5 ft 3 in, or feet to meters. Height chart from 1.40 to 2.10 m plus length and altitude conversions.
Feet to Inches Converter
Convert feet to inches (1 ft = 12 in) and inches to feet. Decimal feet, feet and inches like 5 ft 10 in, fractions, and a chart from 1 to 100.
Liters to Gallons Converter
Convert liters to US or UK (imperial) gallons and back, with exact NIST factors. Chart for bottles, fuel tanks, aquariums and coolers.
Cups to mL Converter
How many mL in a cup? Convert US customary, US nutrition-label (240 mL), metric (250 mL) and imperial cups to milliliters, with fractions and a chart.
Ounces to Grams Converter
Convert ounces to grams (1 oz = 28.349523125 g) and grams to ounces. Fractions like 1 1/2 oz, troy ounces, the fluid-ounce caveat and a chart.
Ounces to Pounds Converter (oz to lb)
Convert ounces to pounds (16 oz = 1 lb) and pounds to ounces. Get decimal pounds or lb + oz for baby weight, shipping and recipes, with a full chart.
Grams to Pounds Converter (g to lb)
Convert grams to pounds (1 lb = 453.59237 g) and pounds to grams, with pounds and ounces. 500 g = 1.102 lb. Chart from 1 g to 10,000 g.
Cm to Feet and Inches Converter (Height)
Convert centimeters to feet and inches for height (170 cm = 5 ft 7 in) and feet to cm. Height chart from 120 to 220 cm, with fractions and rounding.
Ounces in a Gallon (Cups, Pints, Quarts & mL)
There are 128 fl oz in a US gallon and 160 in an imperial gallon. Convert gallons to ounces, cups, pints, quarts and mL, and back, with daily water charts.
Square Feet to Acres Converter
Convert square feet to acres (1 acre = 43,560 sq ft) and acres to square feet. Measure a lot by length × width, with lot-size charts and m² and hectares.
Knots to MPH Converter (Knots, mph & km/h)
Convert knots to mph (1 kn = 1.15078 mph) and km/h, and back. Wind, boat and aircraft speed charts, the Beaufort scale and why a knot is one nautical mile per hour.