Pond Calculators

Every number you need to plan and run a healthy koi pond or water garden. Free, instant, and sized to real pond equipment.

Pond & build

Start here when planning a pond.

Gallons & liters from your dimensions, any shape.

Liner and underlayment size with overlap.

Reservoir/basin size for a pondless build.

Estimate the full build cost of your pond.

Move and circulate the water.

Pump flow for healthy turnover.

GPH for your spillway width and head height.

Air pump and diffuser sizing.

Keep the water clear and safe.

UV wattage to beat green water.

Pond salt for your target concentration.

Gallons, liters, °F/°C, ppm and more.

Stock without overloading the pond.

How many koi and goldfish your pond can hold.

Take your calculator results off the screen and onto paper: build planner, stocking planner, water-test log, and seasonal maintenance schedule.