Everyday
Everyday calculators
Dates, conversions, construction, automotive and more.
Time & Date
Age, date differences, duration, time zones, work hours and sleep cycles.
Conversion & Encoding
Unit conversion, shoe sizes, Roman numerals, Base64/URL, passwords and dice.
Engineering & Electrical
Ohm's law, voltage drop, resistor codes, energy cost, bandwidth and subnets.
Construction & Home
Square footage, stairs, tile, gravel, concrete, roofing and mulch.
Automotive & Mechanical
Horsepower, tire size, mileage, gas mileage, fuel cost and speed.
Science & Measurement
Molar mass, density, molarity, heat index, wind chill, dew point and BTU.
Education & Lifestyle
GPA, grades, height, GDP, golf handicap, tip splitting and more.
All everyday calculators
Age CalculatorExact age in years, months and days from a birth date.Date CalculatorDifference between two dates, or add/subtract days from a date.Time CalculatorAdd or subtract two durations in hours, minutes and seconds.Hours CalculatorHours and minutes between a start and end time, less any break.Time Zone CalculatorConvert a clock time from one UTC offset to another.Day CounterCount days, weeks and business days between two dates.Time Card CalculatorDaily hours worked and gross pay from clock-in and clock-out times.Time Duration CalculatorFull duration between two date-times in days, hours and minutes.Day of the Week CalculatorFind which weekday any date falls on.Sleep CalculatorBest bedtimes or wake times based on 90-minute sleep cycles.LLM Token CounterCount tokens and estimate API cost for GPT-5.5, Claude, Gemini 3, Llama 4, DeepSeek, Grok and 60+ more LLMs.Conversion CalculatorConvert length, weight, volume, speed and temperature units.Shoe Size Conversion CalculatorConvert shoe sizes between US, UK, EU and centimeters.Roman Numeral ConverterConvert numbers to Roman numerals and back.Base64 Encode / DecodeEncode text to Base64 or decode Base64 back to text.URL Encode / DecodePercent-encode text for URLs or decode an encoded string.Password GeneratorBuild a strong random password from chosen character sets.Dice RollerRoll any number of dice with any number of sides.Ohm's Law CalculatorSolve for voltage, current, resistance and power from any two values.Voltage Drop CalculatorVoltage drop along a wire run from current, length and conductor size.Resistor Color Code CalculatorDecode a 4-band resistor's value and tolerance from its colors.Electricity Cost CalculatorEnergy use and running cost of an appliance over time.Bandwidth CalculatorDownload/upload time for a file at a given connection speed.IP Subnet CalculatorNetwork, broadcast, mask and host range for an IPv4 address and CIDR.Square Footage CalculatorArea of a room or space and the material cost to cover it.Stair CalculatorNumber of steps, riser height and total run for a staircase.Tile CalculatorTiles and boxes needed to cover an area, including a waste allowance.Gravel CalculatorVolume and weight of gravel needed to fill an area to a depth.Concrete CalculatorConcrete volume and bag count for a slab or footing.Roofing CalculatorRoof area, squares and shingle bundles from footprint and pitch.Mulch CalculatorMulch volume and bag count to cover a garden bed to a depth.Horsepower CalculatorHorsepower from engine torque and RPM.Engine Horsepower CalculatorEstimate horsepower from quarter-mile trap speed and vehicle weight.Tire Size CalculatorOverall diameter, circumference and revolutions per mile from a tire code.Mileage CalculatorFuel economy from distance traveled and fuel used.Gas Mileage CalculatorYearly fuel use and cost from your annual mileage and economy.Fuel Cost CalculatorFuel needed and total cost for a single trip.Speed CalculatorSpeed, distance or time — solve for any one from the other two.Molecular Weight CalculatorMolar mass of a compound from its chemical formula.Density CalculatorSolve density, mass or volume from ρ = m / V.Mass CalculatorMass of an object from its density and volume.Weight on Other Planets CalculatorHow much an Earth weight becomes under other gravities.Molarity CalculatorSolution molarity from solute mass, molar mass and volume.Heat Index CalculatorThe 'feels like' temperature from heat and humidity.Wind Chill CalculatorThe 'feels like' temperature from cold and wind speed.Dew Point CalculatorDew point from air temperature and relative humidity.BTU CalculatorHeating or cooling capacity (BTU/hr) needed to condition a room.GPA CalculatorGrade point average from letter grades and credit hours.Grade CalculatorScore you need on the final to reach a target grade.Height ConverterConvert height between feet/inches and centimeters.GDP CalculatorGross domestic product by the expenditure approach.Golf Handicap CalculatorHandicap differential from a round's score, course rating and slope.Bra Size CalculatorEstimate US bra band and cup size from two measurements.Tip CalculatorTip amount, total bill and the split per person.Love CalculatorA lighthearted compatibility score from two names.