All free online calculators
Browse every free calculator, grouped by what you need to do.
Home improvement
Gravel Calculator
Estimate gravel volume, weight, bags or bulk bags and the expected budget.
Concrete Calculator
Calculate concrete volume and allowance for a slab, patio or footing for free. Plan a delivery, premixed bags or cement, sand and aggregate for site mixing.
Paint Calculator
Calculate paintable area, litres and tins from coverage and number of coats.
Tiles and adhesive
Draw the floor or wall and subtract openings. Calculate tile boxes, optional adhesive and skirting, including waste allowance and price per m².
Terrace Configurator
Draw your terrace and estimate boards or tiles, structure, pedestals, supplies and budget.
Deck Pedestal Calculator
Calculate pedestals from actual joist lines or tile support points.
Paver Calculator
Draw the area and estimate pavers, pallets, allowance and cost.
Flooring Calculator
Draw the room and calculate flooring packs with allowance and budget.
Wallpaper Calculator
Estimate wallpaper drops and rolls from perimeter, wall height and roll dimensions, with an adjustable allowance.
Drywall Calculator
Estimate plasterboard sheets, tracks, studs and screws for a partition.
Insulation Calculator
Calculate insulation area, packs to buy, allowance and budget.
Plaster Calculator
Estimate kilograms and bags of plaster from area, thickness and coverage.
Floor Leveling Compound Calculator
Draw the floor and calculate levelling compound bags from thickness and coverage.
Concrete Block Calculator
Estimate concrete blocks, pallets and allowance required for a wall.
Mortar Calculator
Calculate mortar kilograms, bags and cost from area, product consumption and bag size.
Fence Calculator
Calculate fence panels, posts, total length and budget.
Stair Calculator
Find a practical step count, riser height and going for the available space.
Roof Area Calculator
Calculate the true area of a pitched roof and estimate the number of tiles.
OSB Board Calculator
Draw the area and estimate whole OSB sheets to buy with an allowance.
Excavation Volume Calculator
Draw the footprint and calculate soil to remove and the number of skips.
Geotextile Calculator
Draw the area and calculate geotextile coverage, overlaps and rolls.
Baseboard Calculator
Calculate linear metres and skirting pieces after subtracting doorways.
Home
Linky electricity data analyser
Explore a French Linky meter export and compare electricity tariffs locally in your browser.
Electricity Cost Calculator
Calculate appliance running cost from power, usage time and electricity price.
Battery Runtime Calculator
Estimate battery runtime from capacity, voltage and power consumption.
Solar Panel Calculator
Estimate daily solar production in kWh from installed power, equivalent sunshine hours and system losses.
Pool Volume Calculator
Calculate rectangular pool water volume in m³ and litres from length, width and average depth.
Radiator Size Calculator
Estimate radiator power from room area and your chosen heating requirement in watts per m².
Recessed Lighting Calculator
Estimate spotlights from room area, lumens and desired illuminance.
Water Heater Size Calculator
Estimate water-heater capacity from household size and hot-water use.
Shower Water Usage Calculator
Calculate shower water consumption and water cost from flow rate, duration, frequency and your water tariff.
Cooking Conversion Calculator
Convert millilitres into centilitres and litres when following a recipe or measuring cooking liquids.
Moving Volume Calculator
Estimate moving volume to choose a van or request a quote.
Room Volume Calculator
Calculate room volume in cubic metres from its dimensions.
Electricity
Cable Size Calculator
Estimate cable cross-section from current, length and allowed voltage drop. This guide does not replace an installation safety assessment.
Voltage Drop Calculator
Calculate voltage loss in volts and percent along an electrical circuit.
Watts to Amps Calculator
Calculate amps from power in watts, voltage and power factor for single-phase or three-phase circuits.
Ah to Wh Calculator
Convert amp-hours and watt-hours using battery voltage.
Ohm’s Law Calculator
Calculate resistance and current from voltage and power for a resistive load using Ohm’s law.
Inverter Size Calculator
Estimate inverter power from continuous equipment demand, startup surge and an adjustable safety margin.
kWh Cost Calculator
Convert electricity use into cost using your actual kWh price.
Electric Heating Cost Calculator
Estimate electric-heating use and cost from power, duration and tariff.
Car & transport
Fuel Cost Calculator
Calculate fuel used and trip cost from distance, consumption and fuel price.
EV Charging Time Calculator
Estimate electric-car charging time and cost at home or at a charger.
Car running costs: petrol, hybrid and electric comparison
Compare energy, insurance and maintenance costs using your annual distance. Free yearly and multi-year running cost estimates, excluding purchase and resale.
Travel Time Calculator: Distance, Speed & Stops
Estimate travel time from distance and average speed. Add breaks and a departure time to see your total journey duration and estimated arrival.
Tire Size Calculator
Calculate a tyre’s theoretical outside diameter and circumference from width, aspect ratio and rim size.
Finance
Percentage Calculator
Calculate a percentage, increase, decrease or one value as a share of another.
VAT Calculator
Calculate the VAT amount and gross price from a net price and your entered tax rate.
Loan Payment Calculator
Estimate monthly payment, interest and total loan cost from amount, rate and term.
Borrowing Capacity Calculator
Get a rough borrowing-capacity estimate from income, commitments and an adjustable multiplier. This simplified calculation is not a loan offer.
Car Loan Calculator
Calculate monthly payment, interest and total cost of car finance.
Compound Interest Calculator
Project capital growth with compound interest from initial amount, annual rate and term, without additional contributions.
Savings Goal Calculator
Calculate the monthly saving needed to reach a target by a chosen date.
Unit Price Calculator
Compare two products sold in different pack sizes and quantities.
Discount Calculator
Calculate the sale price and amount saved from the original price and discount percentage.
ROI Calculator
Measure gain, cost and return on investment as an amount and percentage.
Dates & time
Business Days Calculator
Count business days between two dates, excluding weekends and national holidays in the selected calendar, with an option to include the end date.
Weekends Between Dates Calculator
Count complete weekends, Saturdays and Sundays between two dates.
Age Calculator
Calculate your age today in years, months and days from your date of birth.
Days Until Christmas
See the exact number of days remaining until next Christmas.
Days Between Dates Calculator
Count days and calendar duration precisely between two dates.
Days Since Date Calculator
Count days since a date or days until a deadline, with a breakdown into full weeks and remaining days.
Work Hours Calculator
Calculate working time between a start and end time after subtracting a break. Get the total in hours and minutes.
Working Days Calculator
Estimate annual Monday-to-Friday working days after deducting French public holidays and holiday weeks.
Garden
3D pergola configurator
Design your pergola in 3D: dimensions, timber, roofing, fixings to validate, plans and a PDF dossier.
Watering Calculator
Estimate watering consumption and monthly water cost from flow rate, session duration and frequency.
Lawn Calculator
Calculate grass seed kilograms and cost from lawn area, sowing rate in g/m² and price per kilogram.
Hedge Plant Calculator
Calculate hedge plants from hedge length and chosen spacing.
Mulch Calculator
Estimate mulch volume, bags and cost from area and depth.
Rainwater Harvesting Calculator
Estimate harvestable rainwater from roof, rainfall and efficiency to size a tank.
Garden Soil Calculator
Calculate garden soil volume in m³ and litres from the length, width and depth of the layer you want to add.
Health & fitness
One Rep Max Calculator
Estimate your one-rep maximum from a weight and repetitions actually completed.
Running Pace Calculator
Calculate running pace in minutes and seconds per kilometre from distance covered and total time.
Calorie Calculator
Estimate daily calories from weight, height, age and activity. The calculation uses a male equation and is a guide, not a meal plan.
Calories Burned Calculator
Estimate calories burned from activity, duration and body weight.
Target Heart Rate Calculator
Estimate a target heart-rate zone to guide workout intensity.
BMI Calculator
Calculate BMI from weight and height and place the result in context.
BMR Calculator
Estimate resting calorie needs from weight, height and age. This version uses the male Mifflin-St Jeor equation.
Ideal Weight Calculator
Find the weight corresponding to a BMI of 22 for your height. This reference is not a personal target or medical advice.
Pregnancy & cycle
Menstrual Cycle Calculator
Estimate upcoming period dates from the usual cycle length.
Ovulation & Fertile Window Calculator
Estimate an indicative ovulation window from your cycle information.
Late Period Calculator
Count days late compared with the expected period date.
Pregnancy Due Date Calculator
Estimate your due date from the last period and usual cycle length. Pregnancy care may adjust this initial date.
Pregnancy Weeks Calculator
Estimate pregnancy weeks counted from the last period and since conception using a reference date, with weeks and days.
Pregnancy Month & Trimester Calculator
Estimate the pregnancy month and trimester from the last period and chosen reference date.
Conception Date Calculator
Estimate a conception date from the expected due date. This calendar reference cannot establish the actual date with certainty.
Maths & study
Pythagorean theorem calculator
Find the missing side of a right triangle and follow every calculation step.
Equation solver: linear, quadratic and cubic
Solve linear, quadratic or cubic equations with the calculation steps.
Derivative calculator with steps
Differentiate a polynomial or a function containing sine, cosine or tangent, with the rules and calculation steps.
Integral and antiderivative calculator
Find a polynomial antiderivative or evaluate a definite integral for free. Enter the function and optional bounds to see the calculation steps.
Area & Geometry Calculator
Calculate area and perimeter of rectangles, circles, triangles and other common shapes.
3D Volume Calculator
Calculate volume and surface area of cubes, cylinders, spheres and other solids.
Triangle Calculator
Calculate triangle area, perimeter and properties from its sides.
Standard Deviation Calculator
Measure data spread with mean, variance and standard deviation.
Mean Median Mode Calculator
Find mean, median, minimum and maximum for a list of values.
Probability Calculator
Calculate a simple probability from favourable and possible outcomes.
Technical
BTU/h ↔ kW conversion
Convert BTU/h to kW or watts and back to compare air-conditioner capacity. Use the free converter and check the formula and examples.
Airflow and ACH
Calculate airflow or air changes per hour from the room volume.
Duct air velocity and diameter
Relate airflow, air speed and the internal diameter of a circular duct.
IT equipment heat output
Turn the measured electrical input of IT equipment into a room heat load.
Network transfer time
Estimate transfer time while distinguishing bits, bytes, decimal and binary units.
Theoretical usable RAID capacity
Compare raw and theoretically usable capacity for the main RAID levels.