Pool Volume Calculator
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.
Pool Shape
Choose the shape that best matches your pool. Kidney and freeform shapes use a standard industry approximation (0.45 factor).
Pool Dimensions
Measure the longest length and widest width, wall to wall.
Length
Width
Pool Depth
Enter your shallow end and deep end depths. Average depth is calculated automatically. For a flat-bottom pool, enter the same value for both.
Shallow End
Deep End
Pool Volume
15,148 gal
57,341 liters
Use this volume in your pool chemistry calculators
Your pool volume is the starting point for dosing chlorine, CYA, shock, algaecide, and salt. Use the number above whenever a pool calculator asks for pool volume.
Calculations use the standard 7.48052 gallons per cubic foot conversion.
💡About this calculator▼
Before you add a single chemical to your pool, you need to know how many gallons it holds. Every chemical dosing recommendation — chlorine, shock, CYA stabilizer, algaecide, salt — is calculated per 10,000 gallons. Get this number wrong and you'll either underdose (ineffective treatment) or overdose (wasted money, potential damage to equipment and swimmers).
This calculator covers rectangular, oval, round, and kidney-shaped pools. Enter your dimensions and depth and get an accurate gallon count in seconds.
The calculator multiplies your pool's surface area by its average depth to get the volume in cubic feet, then converts to gallons using the standard conversion factor of 7.48052 gallons per cubic foot. Surface area is computed differently for each shape: length × width for rectangular pools, the stadium formula (rectangle + two semicircular ends) for oval pools, the circle formula (π × radius²) for round pools, and the 0.45 industry shape factor for kidney and freeform pools. Average depth is calculated as (shallow end + deep end) ÷ 2.
📐How it's calculated▼
Rectangular: Volume (gal) = Length × Width × Average Depth × 7.48
Oval (flat-sided stadium shape): Surface Area = (Length − Width) × Width + π × (Width ÷ 2)² Volume (gal) = Surface Area × Average Depth × 7.48
This models the real-world construction of oval pools: a rectangle with one semicircular end on each side. A 30 × 15 ft oval has roughly 402 sq ft of surface area — about 14% more than a pure ellipse.
Round (circular): Volume (gal) = π × (Diameter ÷ 2)² × Depth × 7.48
Kidney / Freeform: Volume (gal) = 0.45 × Length × Width × Average Depth × 7.48
Average Depth: Average Depth = (Shallow End Depth + Deep End Depth) ÷ 2
The 0.45 factor for kidney shapes is the standard industry approximation. It represents roughly 45% of the bounding rectangle being filled with water, which matches the typical kidney and figure-eight contour.
📎Source: Pool & Hot Tub Alliance (PHTA) water chemistry standards and industry pool volume calculation methodology
🔍Finding your inputs▼
Pool Shape: Choose the shape that best matches your pool. If your pool has an irregular shape not listed, estimate using the nearest shape. Kidney and freeform pools typically vary ±5–10% from the calculation depending on the exact contour — this is normal and acceptable for chemical dosing purposes.
Pool Length / Width: Measure from the inside wall to the inside wall at the longest and widest points. Do not measure across the coping or the deck. For oval pools, measure the full length and full width, not the radius.
Pool Diameter: For round pools, measure across the widest point from inside wall to inside wall.
Shallow End Depth: Measure from the water surface to the pool floor at the shallowest point — typically near the steps or the entry end. For above-ground pools with a flat bottom, use the actual water depth, not the pool wall height.
Deep End Depth: Measure from the water surface to the pool floor at the deepest point. For flat-bottom pools, enter the same value as the shallow end depth.
⚠️Special situations▼
Pool has a beach entry or zero-edge design
Beach entry pools gradually slope from the deck to full depth. Estimate average depth conservatively — the sloped entry holds significantly less water than a vertical-walled pool of the same footprint. A rough adjustment is to subtract 10–15% from the calculated volume.
Pool has a tanning ledge, wading shelf, or baja step
Calculate the main pool volume normally. Then estimate the ledge or shelf as a separate rectangle: length × width × shelf depth × 7.48. Add the two volumes together for total gallons.
Above-ground round pool: wall height vs. water depth
The water depth is always 6–12 inches less than the wall height. A pool advertised as "52 inches deep" has a wall height of 52 inches — the actual water depth is typically 44–48 inches (3.7–4.0 ft). Always measure actual water depth when the pool is full.
Kidney pool result seems too low
The 0.45 shape factor is conservative for pools that are closer to oval than kidney. If your pool is a gentle curve rather than a true kidney, calculate using the Oval option for a higher estimate, then average the two results. The true volume is likely between them.
❓Common questions▼
How many gallons is a typical in-ground pool?
A standard residential in-ground pool — roughly 30 ft × 15 ft with a 3.5 ft shallow end and 6 ft deep end — holds approximately 15,000 to 17,000 gallons. Smaller pools (20 × 10) hold around 5,000 gallons. Larger pools (40 × 20) can hold 30,000+ gallons. Above-ground round pools typically hold 3,000–12,000 gallons depending on diameter and depth.
Why does pool volume matter for chemical dosing?
Pool chemicals work by concentration — parts per million (ppm) in the water. To raise the concentration by 1 ppm, you need 1 mg of chemical per liter of water, which works out to a precise number of ounces or pounds per gallon of pool water. If you overestimate your pool size, you add too little chemical and the treatment fails. If you underestimate, you add too much and waste product, potentially causing water issues or irritation.
How accurate is the kidney shape factor?
The 0.45 factor is the standard used across the pool industry and is accurate within ±5–10% for most true kidney and figure-eight shapes. The factor approximates the ratio of a kidney's area to its bounding rectangle. For chemical dosing, this level of accuracy is entirely sufficient — a 10% error means 1.5 oz of chlorine instead of 1.7 oz in a 10,000-gallon pool.
Should I use gallons or liters for chemical dosing?
In the US, nearly all pool chemical labels show dosage in ounces or pounds per 10,000 US gallons. Use the gallons figure. The liters figure is included for reference — useful if you buy European products or use a metric test kit.
My pool builder gave me a different volume. Which is correct?
Pool builder estimates are often rounded to the nearest 1,000 gallons and may use slightly different shape factors or depth assumptions. Small differences (5–10%) are normal. For chemical dosing, either number is accurate enough. If there is a large discrepancy (>15%), measure your pool dimensions independently — the calculator is only as accurate as the dimensions you enter.
🔗 Related Calculators
Algaecide Dosing Calculator
Calculate exactly how much algaecide to add to your pool. Enter your pool volume and algaecide type to get the precise dose for weekly prevention, season opening, or treating an active algae outbreak.
Cyanuric Acid Dosing Calculator
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.
Pool Heating Cost Calculator
Calculate exact monthly pool heating costs for gas, electric, or heat pump systems. See seasonal expenses and compare heating methods.
Pool Salt Calculator
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.
Chlorine Dosing Calculator
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.
Pool Shock Treatment Calculator
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).