Every dose calculation — chlorine, acid, baking soda — depends on getting your volume right. Select your pool's shape and enter its dimensions.
Every chemical dose is calculated per gallon. Add 20% too little chlorine because you underestimated your pool size and you'll be chasing algae all summer. Add 20% too much acid and you'll overshoot your pH target every time. Volume is the one number that makes every other calculation correct — or wrong.
For length and width, a tape measure along the water line is the most accurate method. For depth, use a telescoping pole or measuring rod. Measure at the shallow end, the deep end, and two or three spots in between. For a pool with a sloped bottom, average depth = (shallow depth + deep depth) ÷ 2, which is what the "Sloped" option above calculates.
For unusual shapes, the approach is always the same: break the pool into sections you can measure, calculate each section, and add them. An L-shaped pool is two rectangles. A kidney pool has two lobes — the (A + B) formula approximates the curved boundary.
Pool walls aren't perfectly vertical, floors aren't perfectly flat, and tape measures aren't perfectly level. A well-measured pool still has ±5–10% error. Dose chemicals conservatively — you can always add more, but you can't easily remove what's already in.
The constant 7.48 converts cubic feet to US gallons. The oval and round constant 5.9 is π/4 × 7.48 ≈ 5.87, rounded to 5.9. The kidney constant 0.45 accounts for the indented-lobe geometry and is consistent with the Pool & Hot Tub Alliance standard.
Enter your pool volume once in PoolChem Tracker and every recommendation — chlorine, acid, baking soda, calcium chloride — calculates the exact dose for your pool size automatically.
