Backyard Pool Calculators
Plug in your own numbers and get a real answer — the exact dose, the right target, or which option wins for your setup. Same math behind our verdicts. No sign-up. Start with the interactive pool tools up top; chemistry, sizing, and cost-of-ownership calculators follow.
Pool tools
Diagnose My Pool
What's wrong and how to fix it — green, cloudy, chlorine smell, chlorine won't hold, high CYA / 'chlorine lock', mustard algae.
Pick a symptom, enter a couple of numbers, get the diagnosis + exact target + fix.
Open the calculator Pool · Track itPool Tracker (free logbook)
Log every test, get each number judged against the right target for your pool + the exact dose, and watch the trends. No account, nothing uploaded.
A free, on-device pool logbook — no account, and your test history never leaves your browser.
Open the calculator Pool · DosingChemical Dosing Calculator
Exactly how much liquid chlorine, muriatic acid, baking soda, calcium, stabilizer, or salt to add for your gallons and target — plus the free-chlorine target for your CYA.
Add the right amount, not a guess — the same math behind every dose in Pool School.
Open the calculatorPool chemistry
FC Target Calculator
Your minimum, target, and SLAM chlorine for YOUR CYA — with a verdict if you enter your current FC.
Free chlorine is a ratio, not a fixed number — the same published chart rows as our FC/CYA guide, snapped honestly.
Open the calculator Pool · Water balanceWater Balance Calculator (LSI/CSI)
Is your water corrosive, balanced, or scaling? The one index that ties your five numbers together.
Every number can read "in range" while the water still etches plaster or scales your heater.
Open the calculator Pool · ChlorineThe Chlorine Showdown
Raising your free chlorine — liquid vs. trichlor vs. cal-hypo vs. dichlor, head to head, judged on the hidden cost each one adds.
Same chlorine, four costs: trichlor piles on CYA, cal-hypo adds calcium, liquid adds almost nothing.
Open the calculator Pool · Salt cellSalt Cell Run-Time & Lifespan
Free chlorine made per day at your output % and pump hours — plus how that setting sets the cell's lifespan, and why sizing up makes it last.
The cell is the expensive part. See what your % is doing to how long it lasts.
Open the calculator Pool · High CYACYA Drain & Refill Calculator
How much water to replace to bring high CYA back to target — percentage, gallons, and a staged plan for deep drains.
CYA only leaves with the water. The math is proportional — no reducer bottle required, and we'll say so.
Open the calculatorSizing & setup
Pool Volume Calculator
How many gallons is your pool? Every shape — including both kinds of oval and a real diving-pool depth mode.
The (shallow+deep)÷2 shortcut overstates a diving pool 10–15% — and every chemical dose with it.
Open the calculator Pool · HeaterPool Heater Finder
Heat pump, gas, or solar — what size, what it should cost to run per year, and which contender your gallons actually land on. Answer your gallons, above/in-ground, region, season and goal.
Most guides pick a type OR a size. This picks both for your pool, prices the year, and names the exact unit waiting for you — plus the ~50°F heat-pump floor and the no-tax-credit truth.
Open the calculator Pool · CoolerPool Cooler Finder
Your pool is too hot — what actually fixes it? Answer your gallons, your summer air, whether you have a screen cage, and what matters most, and get the technology, the BTU, the run cost, and the unit to buy.
Your air picks the technology and your gallons pick the machine. It will tell you plainly when evaporative cooling cannot work where you live — the thing no product page admits.
Open the calculator Pool · Pump sizingPool Pump Sizing Calculator
Enter your gallons and get the flow you need, the sand filter that handles it, and the pump HP that matches — sized by flow, not horsepower.
A bigger-HP pump channels a sand filter and cleans WORSE. This finds the right size, and warns you off oversizing.
Open the calculatorCost & ownership
Pool Heating Cost Calculator
Heat pump vs gas vs solar — what each really costs to run, and which is cheapest to own.
Draws the 10-year crossover + the honest ~50°F heat-pump floor.
Open the calculator Pool · PumpsPool Pump Savings Calculator
What a variable-speed pump saves you every year versus a single-speed.
Most single-speed owners are quietly losing $500–$900 a year.
Open the calculator Pool · SanitizingSalt vs Chlorine Cost Calculator
Is a salt pool actually cheaper? The real 10-year math, cell replacement included.
Spoiler: salt ≈ chlorine once you count the cell.
Open the calculator Pool · CoolingPool Cooling Cost Calculator
What dropping your pool 5°F actually costs — chiller vs heat/cool pump vs evaporative vs aerator, honest about humidity.
Evaporation is $1.80 a night where it works. Know if it works where you live.
Open the calculator Fire & Heat · Fire tablesFire Table Run Cost Calculator
What an evening around a gas fire table actually costs — propane by the gallon or natural gas by the therm, on your own gas price.
No fire table listing publishes this. $2.30 an hour on propane, 90¢ on a gas line — and 7.2 hours from a full 20-lb tank.
Open the calculator Pool · RobotsPool Robot Cost Calculator
A robot versus paying for pool cleaning — and exactly when it pays for itself.
Stack years of service fees against one upfront robot.
Open the calculator Pool · RobotsPremium Robot vs Pool Service Calculator
Does a $2,000+ robot beat paying the pool guy — and when does it break even?
A $2,199 robot vs a $120/month service: ~19 months to even.
Open the calculatorFit & furniture
Ledge Fit Checker
Yes, this exists: type in your tanning ledge — depth, width, water — and watch every in-pool chair and chaise we cover pass or fail on the spot.
Seats-across, the exact riser size your depth needs, honest 'won't fit' verdicts — every footprint straight from the maker's spec sheet. Nobody else has this.
Open the calculator Furniture · FitPatio Fit Planner
Measure your patio, pick how it’s bounded, and see how much seating footprint is actually left once people can still walk past it — then which sofa sets fit inside it.
It also names the four sellers whose “product dimensions” are a shipping carton, and refuses to guess a footprint from one.
Open the calculatorEvery calculator uses the same figures as the matching showdown or Pool School guide — and more land as we test new gear.