Everyday Calculators
Free everyday calculators for dates, ages, time, grades, GPA, and tips. Simple tools for common day-to-day calculations.
83 tools in 9 groups
Most popular
- Age CalculatorFind an exact age in years, months, and days from any date of birth, along with the total in weeks, days, hours, and minutes.
- Date CalculatorCount the days, weeks, and business days between two dates, or add and subtract any interval from a starting date.
- Time CalculatorUse the Time Calculator to add or subtract durations, or calculate a same-day or overnight shift after an unpaid break.
- GPA CalculatorCalculate your grade point average on the standard 4.0 scale by entering each course's letter grade and credit hours.
Date & Time
- Age CalculatorFind an exact age in years, months, and days from any date of birth, along with the total in weeks, days, hours, and minutes.
- Date CalculatorCount the days, weeks, and business days between two dates, or add and subtract any interval from a starting date.
- Time CalculatorUse the Time Calculator to add or subtract durations, or calculate a same-day or overnight shift after an unpaid break.
- Hours CalculatorCount the hours between two clock times. Enter a start and end time (12-hour or 24-hour), subtract an unpaid break, and get the result in hours and minutes and as the decimal hours timesheets use. Shifts that cross midnight are handled automatically; add an hourly rate to see the pay.
- Time Card CalculatorAdd up a week's timesheet. Enter clock-in and clock-out times and break minutes for each day, and the calculator totals the hours, splits regular from overtime under the rule you choose, and works out gross pay from your hourly rate. The link in your address bar saves the whole card.
- Day CounterCount the days from one date to another — days until a deadline, days since an event, or the length of a stay. The counter gives the total days, the same span as weeks, and a breakdown into weekdays, weekends and business days, with the option of counting both the start and end dates.
- Day of the Week CalculatorFind out what day of the week any date falls on — the day you were born, a historical event, a date years ahead. The calculator gives the weekday together with the day of the year, the ISO week number, whether the year is a leap year, and the weekday of the same date in surrounding years, and shows Zeller's congruence so you can check it by hand.
- Time Duration CalculatorMeasure the exact time between two moments. Enter a start date and time and an end date and time to get the duration as days, hours and minutes, as years, months and days, and as a total in weeks, days, hours, minutes and seconds. Spans of a few hours or a few years work the same way.
- Business Days CalculatorCount working days, not calendar days. Find the number of business days between two dates, or the date a number of business days from now — for delivery estimates, contract deadlines, payroll and leave. Weekends are always skipped; US federal holidays can be too, and the calculator lists the ones it skipped.
- Sleep CalculatorPlan bedtime or wake time from your chosen sleep duration and time to fall asleep.
- Time Zone CalculatorConvert a dated local time between IANA time zones, with explicit handling of daylight-saving gaps and repeated clock times.
Home & Building
- Square Footage CalculatorCalculate square footage for rectangles, circles, triangles, trapezoids and borders, add up to four areas, then include waste and a price per square foot.
- Paint CalculatorEstimate liters and containers of paint from a net area or from room length, width and height minus doors and windows, for any number of coats.
- Wallpaper CalculatorEstimate full wallpaper rolls from strip width, wall height, trim allowance and a straight-match vertical pattern repeat.
- Flooring Cost CalculatorEstimate complete flooring packs and total material, labor and fixed-extra costs using net floor area and cutting allowance.
- Fence CalculatorCount bays, posts and rails for one straight open fence run and estimate the entered post-and-rail material cost.
- Deck Board CalculatorEstimate stock deck boards from deck dimensions, actual board width, inter-row gap and available stock length.
- Roof Pitch CalculatorConvert rise and horizontal run to roof pitch, angle, slope percentage, sloping length and a plan-area multiplier.
- Stairs CalculatorDivide a total finished-floor rise into equal risers and estimate tread count and horizontal run from your design inputs.
- Pool Volume CalculatorEstimate water volume for a rectangular pool with a uniformly sloping bottom, in liters, cubic meters and US gallons.
- Water Flow CalculatorCalculate average flow from the volume collected over a measured time and convert among common flow-rate units.
- Pipe Volume CalculatorCalculate the full internal capacity of a straight circular pipe using its actual bore diameter and length.
- Concrete CalculatorEstimate concrete for slabs, footings, round columns, tubes, steps and curbs in cubic yards, feet and meters, with 40, 60 or 80 lb bag counts and cost.
- Mulch CalculatorCalculate mulch or topsoil for rectangular, circular or triangular beds in cubic yards and feet, with 0.75 to 3 ft³ bag counts, topsoil weight and cost.
- Gravel CalculatorEstimate gravel for rectangular, circular or triangular areas and roadway or trench fill, in cubic yards, metric tonnes and US short tons, with cost.
- Tile CalculatorEstimate tiles, complete boxes and material cost from net surface area, tile size and an allowance for cuts and breakage.
- Feet and Inches CalculatorAdd, subtract, multiply or divide tape-measure lengths in feet, inches and fractions of an inch, and get the answer rounded to the nearest 1/16 inch plus decimal feet and metric.
- Roofing CalculatorEstimate sloped roof area from the building footprint, overhang and pitch, then the roofing squares and shingle bundles to order with waste, and an optional cost.
- Cubic Yard CalculatorEnter the length, width (or diameter) and depth of one or more areas to find how many cubic yards or cubic feet of soil, mulch, gravel or concrete you need, what it costs and how many bags to buy.
Electrical
- Voltage Divider CalculatorCalculate a two-resistor divider’s output, input current and resistor dissipation, including an optional resistive output load.
- Resistor Color Code CalculatorRead 4-, 5- or 6-band resistor colors as ohms with tolerance and ppm/K drift, or enter a resistance to get its bands and the nearest standard E-series value.
- Capacitor Energy CalculatorCalculate ideal stored energy and charge magnitude from capacitance in microfarads and capacitor voltage.
- Electricity Cost CalculatorEstimate appliance energy and cost using watts, daily running hours, days, duty fraction and your electricity unit price.
- Ohm’s Law CalculatorEnter any two of voltage, current, resistance and power to solve the other two for an ideal resistor, with the working shown.
Science & Engineering
- Density CalculatorCalculate density from mass and volume, or rearrange ρ = m/V to find mass or volume when you know the density.
- Molar Mass CalculatorCalculate molar mass from a chemical formula, including grouped atoms and hydrates, using CIAAW abridged standard atomic weights.
- Dilution CalculatorCalculate stock volume for a target concentration and final solution volume using conservation of solute.
- Molarity CalculatorCalculate mol/L and mmol/L from solute mass, molar mass and final solution volume.
- Kinetic Energy CalculatorFind kinetic energy from mass and speed, or rearrange K = ½mv² to solve for mass or speed, with each substitution shown.
- Potential Energy CalculatorFind potential-energy difference from mass, height and gravity, or rearrange U = mgh to solve for mass, height or gravity.
- Acceleration CalculatorFind average acceleration from two velocities and a time, or solve for final velocity, initial velocity or elapsed time.
- Force CalculatorFind net force from mass and acceleration or solve for either, or switch to weight mode to get W = mg or mass from weight on Earth, the Moon, Mars or Jupiter.
- Pressure CalculatorFind average pressure from force and area, or solve for the force or the loaded area when you know the pressure.
- Wavelength CalculatorFind wavelength from speed and frequency, or solve for the frequency or the propagation speed, with the working shown.
- Half-Life CalculatorSolve a constant half-life decay model in either direction, or convert between half-life, decay constant and mean lifetime using your chosen time unit.
- Kinematics CalculatorPick the two unknowns, enter the other three of displacement, initial velocity, final velocity, acceleration and time, and get the answer with every equation shown.
- Hooke's Law CalculatorEnter two of spring force, spring constant and extension to find the third, or start from stored energy U to find k or x, with the spring energy shown.
- Friction CalculatorFind the friction force from the coefficient of friction and normal force, or work out the coefficient from a measured force, on a flat surface or a slope.
- Momentum CalculatorCalculate linear momentum from mass and velocity or solve for either one, then use impulse to connect a force acting over time with the change in motion it causes.
- Work and Power CalculatorWork out the work done by a force over a distance at any angle, the power delivered over a time, or rearrange to find the force, work or time.
- Mass-Energy Equivalence CalculatorEnter a mass to find its rest energy, or an energy to find the equivalent mass, using Einstein's mass-energy equivalence and exact SI constants.
- Ideal Gas Law CalculatorEnter any three of pressure, volume, amount of gas and temperature to find the fourth, with unit conversions and the full PV = nRT working.
- Horsepower CalculatorFind mechanical power in horsepower, kilowatts and PS from torque and engine speed or from force over a distance, or estimate engine horsepower from drag-strip results.
- BTU CalculatorEstimate how many BTU per hour a room loses in cold weather from its size, insulation, windows and air leakage, with every heat-loss term shown so you can check it. This is a heating-load estimate only; it does not size air conditioners or cooling equipment.
Internet & Tech
- Password GeneratorGenerate strong random passwords in your browser using the Web Crypto API. Nothing is transmitted or stored — see the entropy and estimated crack time for each result.
- IP Subnet CalculatorCalculate an IPv4 network, masks, address range and usable hosts, or an IPv6 prefix’s network, first and last address, address count and prefix list.
- Character CounterPaste text to count visible characters, words, whitespace-free characters and bytes. Choose how your custom limit is measured, including emoji-aware character counts.
- Base64 Encoder & DecoderConvert text to Base64 or back to UTF-8 with standard and URL-safe alphabets, or convert an image file to a data URI and Base64 back to a downloadable image.
- URL Encoder & DecoderChoose whether you are encoding one URL value, a complete URI or a form value, then convert text with the appropriate separator and space rules.
- Bandwidth CalculatorEstimate transfer time, work backward from a deadline, convert data units or compare website traffic and billing-period usage with an average connection speed.
Daily Life
- Tip CalculatorCalculate the tip and total for a bill, split it between any number of people, and optionally round the total up to a whole dollar.
- Discount CalculatorWork out a sale price from a percent or amount off, stack a second discount, add tax, or find the percent off between an original and sale price.
- GPA CalculatorCalculate your grade point average on the standard 4.0 scale by entering each course's letter grade and credit hours.
- Grade CalculatorWork out a weighted course grade from scores and weights, or the final exam score needed to reach a target percentage or letter grade, with each step shown.
- Numbers to Words ConverterConvert a number into English words or a US dollar check amount. Decimal digits stay exact, and check amounts are validated before you copy the wording.
- Test Score CalculatorEnter how many questions a test had and how many were missed or correct to get the percentage score, points earned and a letter grade, plus a full chart of scores by number wrong.
- Bra Size CalculatorMeasure your underbust and bust and get the band and cup size defined by the European EN 13402 labelling standard, as a starting point for trying bras on.
- Click CounterTap the button, or press + and − on your keyboard, to keep a running count of people, laps, reps or anything else.
Weather
- Wind Chill CalculatorEstimate wind chill from air temperature and wind speed using the National Weather Service formula.
- Heat Index CalculatorEstimate apparent temperature from air temperature and relative humidity using the NWS method.
- Dew Point CalculatorEstimate dew point from air temperature and relative humidity using a liquid-water vapor-pressure approximation.
Transportation
- Pace CalculatorCalculate running pace, finish time or distance from h:mm:ss or decimal-minute times and min/km or min/mile paces, with speed in km/h and mph.
- Fuel Cost CalculatorEstimate trip fuel, total fuel cost and cost per traveler using distance and fuel economy.
- Gas Mileage CalculatorCalculate US mpg, imperial mpg, km/L and L/100 km from distance or odometer readings and fuel used, plus fuel cost per mile and per kilometer.
- Tire Size CalculatorType the size from your tire sidewall to get its diameter, sidewall height, circumference and revolutions per mile, or compare it with a new size to see the difference and how your speedometer will read.
Fun
- Roman Numeral CalculatorConvert between numbers and Roman numerals with each symbol explained, calculate with two numerals, or turn a date into Roman numerals with your choice of separator.
- Dice RollerRoll custom dice and see each result, the total, possible range and expected average.
- Coin FlipFlip a fair virtual coin, or thousands at once to see how the share of heads settles toward 50%.
- Random PickerPaste a list of names or items and draw one or several at random, or pick random letters or playing cards, with or without repeats.
- Golf Handicap CalculatorEnter your recent 18-hole rounds to estimate a WHS Handicap Index, work out the Score Differential for one round, or convert your index into a Course Handicap for the tees you are playing.
- ERA CalculatorEnter earned runs and innings pitched, in the usual box-score notation, to find a pitcher's ERA for 9-inning or shorter games.
- WHIP CalculatorEnter walks, hits and innings pitched to find a pitcher's WHIP, the average number of baserunners allowed per inning through walks and hits.
- ScoreboardName the teams or players, then tap to add points. The scoreboard shows who is leading and by how much.