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Everyday calculators and handy tools
Dates, home projects, science, tech and photo tools for everyday questions, all free and instant.
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Date & time
Ages, date differences, hours worked and time zones.
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Age Calculator
Your exact age in years, months and days, with totals in weeks, days and hours and the date of your next birthday.
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Date Calculator
Add or subtract years, months, weeks and days from a date, or count the days and weekdays between two dates.
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Time Calculator
Add or subtract days, hours, minutes and seconds from a time, combine two durations, or convert between time units.
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Hours Calculator
Hours worked between a start and end time, minus an unpaid break, in hours and minutes and in decimal hours.
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Time Card Calculator
Weekly time sheet for Monday to Sunday with breaks, overtime after 40 hours and total pay at your hourly rate.
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Time Zone Calculator
Convert a date and time between world time zones, with daylight saving applied, and see the same moment in 40+ cities.
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Time Duration Calculator
The exact time between two dates and times, in days, hours and minutes, with totals in every unit.
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Day Counter
Count the days or weekdays between two dates, with or without the end date, or count down the days to an event.
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Day of the Week Calculator
The weekday for any date from the year 1 to 9999, worked out step by step with Zeller's congruence and the Doomsday rule.
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Sleep Calculator
Bedtimes or wake-up times that fit whole 90-minute sleep cycles, with 4, 5 or 6 cycles and time to fall asleep.
Home & construction
How much concrete, gravel, roofing or tile to buy.
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Concrete Calculator
Concrete for slabs, footings, round columns, circular pads and steps, in cubic yards or m³, plus bags needed.
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Square Footage Calculator
Add up the area of up to six rectangles, circles, triangles, trapezoids or L-shapes in sq ft or m², with cost.
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Stair Calculator
Number of steps, riser height, total run, stringer length and angle, checked against US IRC stair limits.
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Roofing Calculator
Roof area from the house footprint and pitch, with squares, shingle bundles, underlayment rolls and cost.
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Tile Calculator
How many floor or wall tiles and boxes to buy, allowing for grout joints, layout waste and cost per box.
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Mulch Calculator
Cubic yards, cubic feet or m³ of mulch for a garden bed, plus how many 2 or 3 cu ft bags to buy.
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Gravel Calculator
Volume and weight of gravel, crushed stone, sand or topsoil for an area and depth, in tons or tonnes, with cost.
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BTU Calculator
Rule-of-thumb air conditioner size in BTU/h and tons for a room, with a rough heating estimate.
Everyday life
Tips, fuel, grades, sizes and unit conversions.
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GPA Calculator
Semester and cumulative GPA on the 4.0 scale with plus and minus grades, for up to 10 courses.
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Electricity Bill Calculator
Estimate your Pakistan electricity bill from units used, with protected and non-protected slabs, FCA, fixed charges and GST.
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Grade Calculator
Your weighted course grade from category weights and scores, and the score you need on the final exam.
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Height Calculator
Predict a child's adult height from the parents' heights with the mid-parental method, or convert height between cm and feet.
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Tip Calculator
Work out the tip and total on a bill, split it between several people, and round each share up if you like.
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Bra Size Calculator
Estimate your bra size from underbust and bust measurements, in US, UK, EU, French and Australian sizes.
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Shoe Size Conversion
Convert shoe sizes between US men's, women's and kids', UK, EU and Japan, or find your size from foot length.
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Love Calculator
A just-for-fun compatibility score for two names. Same names, same score, every time.
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Golf Handicap Calculator
Your World Handicap System index from recent rounds, plus your course handicap for any set of tees.
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Dice Roller
Roll any number of d4, d6, d8, d10, d12, d20, d100 or custom dice with a modifier, and see the odds of your total.
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Unit Conversion Calculator
Convert length, weight, temperature, area, volume, speed, time, data, pressure, energy, power and fuel economy.
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Roman Numeral Converter
Convert numbers to Roman numerals and back, with the working shown and checks for badly formed numerals.
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Fuel Cost Calculator
The fuel cost of a road trip from distance, fuel economy and price, with round trips and cost per person.
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Gas Mileage Calculator
Your car's real fuel economy in mpg (US and UK), L/100 km and km/L from two fill-ups, plus cost per mile.
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Mileage Reimbursement Calculator
Mileage reimbursement at the 2026 IRS rates for business, medical and charity driving, or your own rate per mile.
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Tire Size Calculator
Compare two tire sizes: diameter, sidewall, circumference, revolutions per mile and the speedometer difference.
Science & engineering
Physics, chemistry, electricity and the weather.
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Ohm's Law Calculator
Enter any two of voltage, current, resistance and power to get the other two, with the working shown.
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Voltage Drop Calculator
Voltage drop, percent drop and voltage at the load for copper or aluminum wire, AWG or mm², single- or three-phase.
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Resistor Color Code Calculator
Read 4-, 5- and 6-band resistor color codes, or find the color bands for any resistance value.
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Electricity Cost Calculator
Energy use in kWh and running cost per day, month and year for any appliance, with typical wattages.
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Horsepower Calculator
Horsepower from torque and rpm, or from force, distance and time, plus hp, PS and kW conversions.
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Engine Horsepower Calculator
Estimate engine horsepower from a quarter-mile time or trap speed and the car's weight.
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Density Calculator
Solve ρ = m ÷ V for density, mass or volume in metric or US units, with common material densities.
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Mass Calculator
Mass from density and volume, or from a weight and the gravity where it was measured, in any unit.
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Weight Calculator
Weight force W = m × g on Earth, the Moon and the planets, in newtons, pound-force and kilogram-force.
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Speed Calculator
Speed from distance and time, distance from speed and time, or time from distance and speed, in any unit.
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Molarity Calculator
Molarity from mass and volume, the mass of solute to weigh out, the volume needed, and C₁V₁ = C₂V₂ dilutions.
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Molecular Weight Calculator
Molar mass of any chemical formula, with brackets and hydrates, and the mass percent of each element.
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Wind Chill Calculator
Wind chill (feels-like) temperature with the NWS formula, in °F or °C, with the frostbite risk.
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Heat Index Calculator
Heat index (feels-like temperature) from air temperature and humidity with the NWS method, in °F or °C.
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Dew Point Calculator
Dew point from temperature and relative humidity, or humidity from temperature and dew point, in °F or °C.
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GDP Calculator
GDP from C + I + G + (X − M), real GDP with a deflator, growth between two years, and GDP per person.
Tech & internet
Subnets, bandwidth, passwords and text encoding.
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IP Subnet Calculator
Network and broadcast address, usable host range, masks and binary view for any IPv4 or IPv6 subnet.
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Bandwidth Calculator
How long a download or upload takes, how much data a connection moves, and a website's monthly bandwidth.
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Base64 Encode and Decode
Encode text to Base64 or decode Base64 back to text, with full UTF-8 support and the URL-safe variant.
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URL Encode and Decode
Percent-encode text or whole URLs, decode them back, and see any URL split into its parts and query parameters.
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Password Generator
Strong random passwords or word passphrases made in your browser, with the entropy and a strength rating for each.
Image tools
Edit photos right in your browser, with no upload.
Other kinds of calculators
- Financial calculators — 83 tools
- Fitness & health calculators — 29 tools
- Math calculators — 44 tools
- PDF tools — 25 tools
- Video downloaders — 3 tools