Pool & Spa Calculators
16 calculators16 free calculators for pool & spa homeowners.
Algaecide Dosing
Calculate exactly how much algaecide to add to your pool for weekly prevention, season opening, or an active bloom — with step-by-step guidance for treating green, yellow (mustard), and black algae. Enter your pool volume and algaecide type for the precise dose.
Chlorine Dosing
Calculate exactly how much chlorine to add to your pool. Enter your pool volume, current and target free chlorine levels, and chlorine product type to get the precise dose.
Cyanuric Acid Dosing
Calculate exactly how much cyanuric acid (pool stabilizer) to add to raise CYA to your target level — or how many gallons to drain if CYA is too high. Includes minimum free chlorine guidance.
Fiberglass Pool Repair vs. Reseal
Compare spot-repairing your fiberglass pool's gelcoat damage against resealing (refinishing) the whole interior. See what each costs by pool size and damage extent — and why osmotic blistering means you must resurface, not patch.
Hot Tub Running Cost
Estimate the yearly cost to run a hot tub or Jacuzzi — electricity, chemicals, water, and filters. Electricity is the big one; see your annual and monthly cost, what drives it, and how a good cover and lower temperature cut the bill.
Pool Deck Resurfacing Cost Estimator
Estimate pool deck resurfacing costs by material — Kool Deck, concrete overlay, stamped concrete, or pavers. Enter your deck area and condition for an instant project cost range.
Pool Fill Cost
Estimate the cost to fill or top off a swimming pool with water. Compare city/tap water vs. bulk water delivery, account for sewer charges and the common pool-fill exemption, and see the fill time. (For removing or filling in a pool, see our pool removal calculator.)
Pool Filter Replacement Cost
Calculate pool filter replacement costs for sand, cartridge, and DE filters. See if your filter is overdue and estimate your 5-year maintenance cost.
Pool Heating Cost
Calculate exact monthly pool heating costs for gas, electric, or heat pump systems. See seasonal expenses and compare heating methods.
Pool Installation Cost Estimator
Estimate what a new swimming pool will cost to install. Compare gunite, fiberglass, vinyl, and above-ground pools by size, add heater, deck, fencing, and more, and see a realistic low-to-high price range.
Pool Pump Energy Cost
Estimate what your pool pump costs to run per year by type, horsepower, run hours, and electricity rate — and see what a variable-speed pump would cost for the same job, the annual savings, and how fast the upgrade pays for itself.
Pool Removal Cost
Estimate the cost to remove or fill in an inground pool. Compare partial fill-in vs. full pool demolition by pool size, material, site access, and debris disposal — and see what it costs to fill in a swimming pool.
Pool Salt
Calculate exactly how much salt to add to your pool. Enter your pool volume, current salt level, and target ppm to get the precise weight and number of 40-lb or 50-lb bags needed.
Pool Shock Treatment
Calculate exactly how much pool shock or bleach you need. Supports HTH, calcium hypochlorite, and liquid chlorine for any pool size (e.g. 12,000 gallons).
Pool Volume
Calculate your pool volume in gallons for rectangular, oval, round, and kidney-shaped pools. Enter length, width, and depth to get an accurate gallon count for chemical dosing.
Spa Electrician Cost
Estimate what an electrician charges to wire a hot tub or spa — the 240V circuit, code-required GFCI disconnect and bonding, wire run, trenching, and a possible panel upgrade. See the cost by run distance, amperage, and whether your panel needs upgrading.
About Pool & Spa Calculators
Owning a pool or spa means making expensive decisions with incomplete information. You need to know exactly how much water your pool holds before you can buy chemicals, plan a drain, or understand your water bill. You need accurate calculations for pump sizing, filter capacity, and heating requirements—get these wrong and you'll either waste thousands on oversized equipment or watch your pool stay cloudy and cold.
This calculator hub gives you the math to make those calls confidently, converting your pool's dimensions into the gallonage and flow rates that actually matter for daily operation and maintenance. Beyond the basics, a pool or spa is a long-term investment that requires precise understanding of costs and timelines. You might wonder if it's cheaper to heat with a gas heater or heat pump, how long it really takes to fill your 20,000-gallon spa, or what size pump you actually need to turn over your water properly.
These aren't academic questions—they determine whether you spend $200 or $1,200 annually on heating, and whether you're maintaining a healthy pool or fighting algae blooms. Our calculators handle the conversions and formulas you don't want to get wrong, so you can make decisions based on actual numbers instead of guesses or salesman recommendations.