Store gallons, preferred targets, and product strengths in this browser only.
Free pool care calculators
Free pool care calculators for every test reading.
Calculate salt, chlorine, pH, alkalinity, stabilizer, volume, pump flow, heating cost, and shock dose from the readings in your hand. Each tool gives the answer first, then the formula, source notes, and retest plan behind it.
No signupUse every calculator free.
Local defaultsSave gallons in your browser.
Formula visibleCheck the math before dosing.
Start here
What do you need to fix?
Pick your situation. We'll send you to the right calculator with sensible starting values.
Low salt reading Salt cell warning — calculate pounds to add. Low chlorine FC dropped below target — estimate liquid or granular dose. Cloudy or green water Need to shock — estimate dose from CYA and gallons. Not sure about gallons Estimate pool volume before dosing chemicals. Pump size or runtime Estimate required GPM before comparing pump curves. Heating cost planning Estimate heat-up cost from gallons, temperature rise, and energy price. pH too high Estimate muriatic acid for a staged pH drop. pH too low Estimate soda ash to raise pH in stages. CYA is off Stabilizer too high or too low — plan the fix. Alkalinity drifting TA out of range — baking soda or acid plan.
Formula first Every calculator shows the math and assumptions behind the result.
References checked Sources include manufacturer manuals, public-health guidance, and dosing formulas.
Local defaults Optional My Pool settings stay in your browser and are never uploaded.
Retest workflow Results are planning numbers with staged additions and retesting built in.
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Choose by problem
Nine calculators for the most common pool math.
The pages are connected: if you do not know gallons, estimate volume first; if you already have a salt, chlorine, pH, alkalinity, circulation, or heating-cost question, go straight to the right calculator.
Saltwater pools
Pool Salt Calculator
Find how many pounds and bags of pool salt to add from your gallons, current salt ppm, and target ppm.
Use when Salt reading is low
You get Pounds, bags, cost, and a staged add plan
- High-salt warning
- 40 lb bag shopping list
- Maintenance log
Free chlorine
Pool Chlorine Calculator
Estimate how much liquid chlorine, bleach, or cal-hypo to add from pool gallons and your target free chlorine raise.
Use when Free chlorine is below target
You get Product amount, ppm raise, side-effect note, and retest plan
- 10% and 12.5% liquid chlorine
- Bleach and cal-hypo options
- Startup and daily dosing
pH adjustment
Pool pH Calculator
Estimate 31.45% muriatic acid or soda ash for staged pH adjustments based on gallons and current pH.
Use when pH is above or below target
You get Conservative dose, first-add amount, and retest guidance
- Lower pH with muriatic acid
- Raise pH with soda ash
- Retest-first guidance
Total alkalinity
Pool Alkalinity Calculator
Estimate baking soda to raise total alkalinity or acid process guidance when alkalinity is high.
Use when Total alkalinity is outside range
You get Baking soda pounds or acid-stage plan with pH warning
- Raise TA with baking soda
- Lower TA with acid and aeration
- Links naturally to pH
CYA / stabilizer
Pool Stabilizer Calculator
Estimate cyanuric acid stabilizer to add from pool gallons, current CYA ppm, and target CYA ppm.
Use when CYA is below or above target
You get Dry stabilizer pounds, ounces, staged add plan, or dilution warning
- CYA dose
- High-stabilizer dilution
- Links to chlorine and shock
Pool gallons
Pool Volume Calculator
Estimate gallons for rectangular, round, or quick surface-area pool measurements before dosing chemicals.
Use when Gallons are unknown
You get A gallons estimate you can send into the salt calculator
- Rectangle and round pools
- Average-depth inputs
- Prefills salt calculator
Pump flow planning
Pool Pump Size Calculator
Estimate required GPM from pool gallons and turnover time, then compare the flow to filter limits and pump curve planning.
Use when Pump size or runtime is uncertain
You get Required GPM, turnover estimate, filter-limit warning, and sizing boundaries
- GPM from turnover
- Filter max-flow check
- Pump curve reminder
Heat-up cost
Pool Heating Cost Calculator
Estimate the cost to heat a swimming pool from gallons, temperature rise, heater type, energy price, and efficiency or COP.
Use when You want to heat the pool
You get BTU needed, runtime, fuel use, heat-up cost, and weather caveats
- Heat pump, gas, propane, electric
- Formula-visible BTU math
- Not an exact monthly bill
Chlorine dose
Pool Shock Calculator
Estimate a shock dose from pool gallons, current free chlorine, target ppm, and product strength.
Use when Chlorine needs a controlled raise
You get Estimated liquid chlorine or cal-hypo amount
- Solid or liquid products
- PPM increase shown
- Safety reminder
STEP 1 Test first
Use a current salt or chlorine reading instead of guessing from last week.
STEP 2 Confirm gallons
Chemical doses scale with water volume, so use a reasonable pool gallons estimate.
STEP 3 Add in stages
Start below the full calculated amount when overshooting would create extra work.
STEP 4 Retest
Circulate, brush if needed, then retest before making a second adjustment.
Methodology
Built for pool math you can check.
Last updated July 8, 2026. Reviewed for formula consistency, source links, product-label boundaries, and conservative dosing language.
Formula visible
Each calculator keeps the formula or table factor near the result so the answer can be audited.
Label first
Product labels, equipment manuals, and local rules override planning estimates.
Transparent methods
Formulas, assumptions, and source notes are shown so the estimate can be checked.
Retest before repeating
Calculations are staged to reduce overshooting and unnecessary chemical stacking.
Pool calculator workflow
Start with the measurement that controls the dose.
Pool chemical math usually starts with two numbers: how many gallons are in the pool and how far the current test reading is from the target. If gallons are uncertain, estimate pool volume first. If gallons are known, use the salt, chlorine, pH, alkalinity, shock, pump size, or heating cost calculator for the problem you need to solve.
The calculators show the result first, then keep the formula visible so the answer can be checked. Salt and chlorine use gallons and ppm change. pH and alkalinity use staged adjustment logic because those readings interact. Volume uses dimensions and average depth.