Free pool tools

Pool Calculators

Turn pool dimensions, water tests, equipment specs, utility rates, and project choices into clear planning answers. Choose a calculator by the job you need to do—no spreadsheet required.

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30 free calculators

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Getting started

3 calculators
Start here Pool Volume Calculator Find your pool's gallons or liters for rectangular, round, oval, kidney, and L-shaped pools. You’ll need: Pool shape and dimensions Open calculator Best for a full water test Pool Chemistry Calculator Work through alkalinity, pH, calcium, CYA, and chlorine in the right balancing order. You’ll need: Pool volume and test results Open calculator Quick multi-chemical dosing Pool Chemical Calculator Get an exact dose for chlorine, pH, alkalinity, calcium hardness, or stabilizer from one tool. You’ll need: Pool volume, current and target levels Open calculator

Dose one adjustment precisely

Water chemistry

12 calculators
Daily sanitizer Pool Chlorine Calculator Calculate liquid chlorine, cal-hypo, dichlor, or trichlor doses using your target and CYA. You’ll need: Gallons, chlorine reading and product Open calculator Algae or heavy use Pool Shock Calculator Find the right shock dose for routine treatment, cloudy water, algae, or a heavy swimmer load. You’ll need: Gallons, current chlorine and shock type Open calculator Sustained algae cleanup SLAM Pool Calculator Match the temporary SLAM target to CYA and calculate each liquid-chlorine dose. You’ll need: Gallons, CYA, current chlorine and bottle strength Open calculator Raise or lower pH Pool pH Calculator See how much muriatic acid, dry acid, or soda ash to add to reach your target pH. You’ll need: Gallons, current and target pH Open calculator Stabilize pH Pool Alkalinity Calculator Calculate baking soda to raise total alkalinity or acid to bring a high reading down. You’ll need: Gallons, current and target TA Open calculator Protect plaster, stop scale Pool Calcium Hardness Calculator Get an exact calcium chloride dose to raise calcium hardness, or the drain-and-refill percentage to lower it. You’ll need: Gallons, surface type, current and target CH Open calculator Lower pH or alkalinity Pool Acid Calculator Get a precise muriatic acid or dry acid dose while accounting for acid strength and pool size. You’ll need: Gallons, test readings and acid type Open calculator Protect surfaces and equipment Pool LSI Calculator Check whether your water is balanced, scale-forming, or likely to etch plaster and grout. You’ll need: Complete water test and temperature Open calculator Saltwater pools Pool Salt Calculator Convert the gap between your current and target salt level into pounds and 40-pound bags. You’ll need: Gallons, current and target salt Open calculator Protect chlorine from the sun Pool Stabilizer (CYA) Calculator Get the exact ounces of granular or liquid stabilizer to raise CYA, or how much water to replace to lower it. You’ll need: Gallons, current and target CYA, product Open calculator Optional borate treatment Pool Borate Calculator Calculate boric acid, laundry borax, or tetraborate from a measured current and target level. You’ll need: Gallons, borate readings and exact product Open calculator Lower dissolved readings Pool Dilution Calculator Find the water-replacement percentage for high CYA, calcium, salt, TDS, borates, or nitrates. You’ll need: Gallons, current, target and fill-water readings Open calculator

Match the system and understand its energy

Equipment & energy

6 calculators
Size pool equipment Pool Pump Size Calculator Estimate the flow rate, horsepower, and pump type needed for healthy circulation. You’ll need: Gallons, turnover time and plumbing Open calculator Program daily pump speeds Variable Speed Pool Pump Schedule Calculator Build a 24-hour schedule from your turnover target and the flow your system produces at each speed. You’ll need: Gallons, turnover target, RPM and GPM Open calculator Hours and energy cost Pool Pump Runtime Calculator Turn actual GPM into runtime, turnover, monthly electricity cost, and an equal-water speed comparison. You’ll need: Gallons, measured GPM, watts and electric rate Open calculator Match filter to flow Pool Filter Size Calculator Size sand, cartridge, or DE filter area from turnover requirements and actual pump flow. You’ll need: Gallons, turnover, pump GPM and filter type Open calculator BTUs, time and cost Pool Heater Calculator Estimate heater class, warm-up time, and energy cost for gas, propane, heat pump, or electric. You’ll need: Gallons, surface area, temperatures and energy rate Open calculator Size the salt cell Salt Chlorine Generator Calculator Match salt-cell pounds-per-day output to chlorine demand, pump runtime, and planned percentage. You’ll need: Gallons, daily FC loss, runtime and cell output Open calculator

Manage refills, weather, seasons, and spas

Water & seasonal

4 calculators
Plan a fill or top-up Pool Fill Time Calculator Calculate hose hours and utility cost from gallons, measured GPM, number of hoses, and water rates. You’ll need: Gallons, hose flow, hoses and utility price Open calculator Estimate water loss Pool Evaporation Calculator Convert weather, surface area, and cover use into a weekly range of inches and gallons. You’ll need: Surface area, temperatures, humidity, wind and cover Open calculator Plan pool closing Pool Winterizing Calculator Estimate closing chlorine, lowered water volume, plumbing volume, and antifreeze planning quantity. You’ll need: Gallons, chemistry, surface area and pipe measurements Open calculator Spa volume and sanitizer Hot Tub Calculator Estimate hot-tub gallons, chlorine or bromine product dose, and partial or full water changes. You’ll need: Known gallons or dimensions, test result and product Open calculator

Budget the build, ownership, and renovations

Cost & planning

5 calculators
Estimate the whole build Inground Pool Cost Calculator Build a project range from construction type, dimensions, market, access, decking, and features. You’ll need: Pool design, site conditions and options Open calculator Plan your budget Pool Loan Calculator Compare monthly payments, total interest, and financing cost across rates and loan terms. You’ll need: Project cost, down payment, rate and term Open calculator Monthly and annual budget Pool Maintenance Cost Calculator Total chemicals, pump energy, heat, water, service, seasonal work, and equipment reserves. You’ll need: Pool season, utility rates and maintenance plan Open calculator Square feet and concrete Pool Deck Calculator Estimate deck area, concrete yards, perimeter, material waste, and installed hardscape cost. You’ll need: Pool dimensions, deck width, finish and local cost Open calculator Plan a new interior Pool Resurfacing Cost Calculator Estimate interior area and cost for plaster, quartz, pebble, polished aggregate, or tile. You’ll need: Pool dimensions, depths, finish and surface condition Open calculator

The numbers are only step one

Use your result with the right guide

Browse all maintenance guides
Weekly Pool Maintenance A simple testing and treatment routine. Clear Cloudy Pool Water Find the cause before adding more chemicals. Clean a Green Pool A complete algae recovery plan. How to Shock a Pool Apply the calculated dose safely.