Pool Salt Calculator

Pool salt formula

Salinity in parts per million is a mass ratio. For water, a rise of 1 ppm needs approximately 1 milligram of salt per liter. The calculator uses:

salt (kg) = pool volume (L) × (target ppm - current ppm) ÷ 1,000,000

A 10,000 US gallon pool contains about 37,854 liters. Raising it from 2,000 to 3,200 ppm is a 1,200 ppm increase, requiring about 45.4 kg or 100.1 lb of salt. A 50 m³ pool moving from 1,500 to 3,000 ppm needs 75 kg.

Quick reference for a 10,000 US gallon pool

The exact-bag result is the amount to dose divided by the package size. The whole-bag purchase count is rounded up so you can buy enough, but it is not permission to empty every purchased bag into the pool. Weigh or measure the remainder from the last bag.

When salinity is above target

Adding salt cannot lower salinity. When tested fill water is below the target, the estimated replacement fraction is:

(current ppm - target ppm) ÷ (current ppm - fill-water ppm)

This is a mixing estimate. It does not account for water trapped in plumbing, incomplete mixing or measurement error. If fill water is at or above the target, replacement alone cannot reach that target.

Dose carefully

• Check the target range in the manual for your exact chlorinator. Common operating values are not universal.
• Confirm salinity independently before adding salt. A chlorinator display may not match a separate test.
• Add in stages with circulation running, brush until dissolved and retest before adding the balance.
• Follow the salt and equipment instructions for where to add it, startup delays and new pool surfaces.
• Treat any water-replacement result cautiously. Pool construction, groundwater and local wastewater or stormwater rules can make draining unsafe or unlawful. Seek local professional guidance when unsure.

The calculation is server-backed. Values entered in the regular calculator are sent to the server for calculation, and funnel values are carried in the page URL so each step can continue.