Pool and hot tub calculators
Pool volume
Gallons for rectangular, round, oval and kidney pools.
Chlorine
How much liquid chlorine, bleach, cal-hypo or dichlor to add.
pH
Muriatic acid or soda ash, adjusted for alkalinity and CYA.
Total alkalinity
Baking soda to raise it, acid to lower it.
Salt
Pounds and 40 lb bags for saltwater pools.
Stabilizer (CYA)
How much cyanuric acid to add, or how much water to drain.
Shock
Routine shock, breakpoint or clearing a green pool.
Calcium hardness
Calcium chloride to raise it, water replacement to lower it.
Hot tub
Chlorine, pH and alkalinity doses for spas.
Why use PoolDose?
Real chemistry, not rough charts
Our pH calculator accounts for your alkalinity and stabilizer, and the chlorine calculator sets your target from your CYA level, the way pool chemistry actually works.
Your pool, remembered
Save your volume once. Every calculator fills it in automatically next time. It stays in your browser only: no account, no email.
Clear and safe
Every result shows the amount in the units on your bottle or bag, how to add it and what to watch out for.
Guides
Pool chemistry basics
The six numbers that matter and their ideal ranges.
Clear a green pool
Step-by-step plan to kill algae and get clear water.
Hot tub water care
A simple weekly routine for clean spa water.
Your weekly pool routine in 4 steps
- Test free chlorine and pH two or three times a week, and total alkalinity, stabilizer and calcium every week or two.
- Adjust pH first with the pH calculator, because pH changes how well chlorine works.
- Top up chlorine to the target for your stabilizer with the chlorine calculator.
- Brush, skim and run the pump long enough to turn over your water at least once a day.