๐ Household
Hot Tub Chemical Calculator
Hot tubs hold far less water than pools, so a teaspoon too much of anything can swing the readings badly. Sanitizer is dosed per 100 gallons rather than per 10,000, and bromine is often preferred because it works better at high temperature.
How it works
Hot tub volume
Current sanitizer level
Target sanitizer level
Sanitizer type
Current pH
Target pH
Current total alkalinity
Sanitizer to add
pH adjuster needed
pH adjustment direction
Baking soda to add
Dosing note
Frequently asked questions
How do I use the Hot Tub Chemical Calculator?
Fill in the fields above โ the result recalculates instantly as you type. Everything runs in your browser, so the values you enter are never collected or stored.
Is this calculator free?
Yes. It is completely free, requires no account, and works on phones, tablets and desktops.