How much pool shock do I need for my pool?

The amount depends on your pool size, current chlorine level, and water conditions. Use the Pool Shock Calculator on Standard Chemicals to determine the exact dose based on your pool.

What is calcium hypochlorite pool shock?

Calcium hypochlorite (cal hypo) is a fast-acting, unstabilized chlorine used to quickly raise chlorine levels, kill algae, and restore water clarity without adding cyanuric acid (CYA).

Does calcium hypochlorite add cyanuric acid (CYA)?

No. Calcium hypochlorite does not add cyanuric acid, making it ideal for pools with high stabilizer levels where additional CYA would reduce chlorine effectiveness.

Why is my pool still green even when chlorine levels are high?

A pool can remain green due to algae growth, poor circulation, or high cyanuric acid levels reducing chlorine effectiveness. In these cases, a stronger shock treatment is typically required.

When should I use pool shock instead of chlorine tablets?

Pool shock is used for rapid chlorine increases to treat algae, cloudy water, and contamination, while chlorine tablets are used for slow, ongoing sanitation and maintenance.

Pool Size Calculator

How many gallons are in my pool?

Not sure how many gallons are in your pool? Enter your pool dimensions below to estimate your pool size in gallons.

For rectangular pools only. This calculator uses a standard pool volume formula and gives an estimate for pools with both a shallow end and a deep end.

Pool Length (Feet)

Pool Width (Feet)

Does Your Pool Have a Deep End?

Pool Depth (Feet)

How to Calculate Pool Gallons

Knowing your pool volume is important when adding chlorine, pool shock, algaecide, stabilizer, and other pool chemicals. If your gallon estimate is too low, you may under-dose your pool. If it is too high, you may add more product than needed.

This pool size calculator is designed for rectangular pools. If your pool has one consistent depth, the math is simple: length × width × depth × 7.48.

How to Measure Your Pool

Length: Measure the longest inside length of the pool in feet.
Width: Measure the inside width of the pool in feet.
Uniform Depth Pools: Measure the water depth in feet.
Shallow/Deep Pools: Measure the shallow-end depth and deepest part of the pool in feet.

Important: This calculator provides an estimate only. Actual water volume may vary based on slope design, hopper shape, steps, tanning ledges, benches, and your actual water fill level.

Why Pool Gallons Matter

Your pool gallon count affects nearly every chemical treatment decision, including:

How much pool shock to add
How many chlorine tablets to use
Proper algaecide dosing
pH, alkalinity, and calcium hardness adjustments

Once you estimate your gallons, you can more accurately dose your pool chemicals and keep your water cleaner, safer, and easier to maintain.

Please use our Pool Shock Calculator to understand your suggested calcium hypochlorite dosage and Chlorine Tablet Calculator to understand your suggested weekly tablet usage to maintain a crystal clear pool all summer long.

Helpful Tip

If your result seems slightly higher than expected, that is intentional. This calculator is built to lean a little high for variable-depth pools so pool owners have a more conservative estimate when calculating chemical dosage.