Free Pond Calculators and Apps
Plan your pond, understand your water, and keep pond care on track. Every tool on this page is free to use, and only the Pond Tracker asks you to sign in.
Built from years of sizing real ponds and answering the same questions by phone. Work out your gallons before you buy a pump, read a water test without guessing, and keep a record of what you did and when.
Pond apps
Three free apps that work together. A water test you read in Pond Chemist is saved to your Pond Tracker, and the Tracker knows the ponds you sized in the Planner.
Pond Planner
Design your pond in 3D and size your equipment. Shape, depth, liner, volume, pumps and filtration, with a build sheet at the end.
See what it does Open the Pond PlannerPond Chemist
Understand your water tests and what to do next. Type in the numbers from any test kit and read what each one means for your koi.
Explain my results No sign-in neededPond Tracker
Track water, koi, feeding, treatments and maintenance, with reminders on your phone. Free with your Play It Koi account.
Start tracking free Look around a sample pondPond calculators
Answers to the questions we are asked most. Start with your volume: the other four all depend on it.
Pond volume calculator
How many gallons your pond holds. Draw the shape, set the depth, and get the number that sizes your pump, your filter and every dose you measure.
Work out my gallonsPond liner calculator
How much pond liner you need, with the overlap and the underlayment, plus the box welded size if you want a liner made to fit.
Size my linerPond pump sizing calculator
What size pump your pond needs, by volume, waterfall width and the head your plumbing adds.
Size my pumpPond aeration calculator
What size air pump your pond needs, from its size, depth and fish load, with running costs for the year.
Size my air pumpUV sterilizer sizing calculator
What size UV your pond needs for clear water, by gallons and flow rate, and where it belongs in your filtration.
Size my UVSimulators and finders
See how the equipment works before you buy it, and find the part or the people you are looking for.
- Gravity fed rotary drum filter simulator: watch how a gravity fed drum filter cleans itself, and where the water level sits.
- Pump fed rotary drum filter simulator: the same filter plumbed the other way, and what changes.
- PerformancePro pump parts finder: find the right seal, impeller or motor for your pump.
- Planting zone and frost dates: your zone and first and last frost by ZIP code, for pond plants and winter prep.
- Find a koi club: koi clubs and societies by state.
Equipment buying guides
Longer reads behind the numbers, written from years of selling and supporting this equipment.
- Pond pump sizing guide: what size pump you need, by volume, waterfall width and total dynamic head.
- Friction loss and plumbing guide: pipe size, fitting losses, and why your flow drops.
- Pond aeration and air pumps: diaphragm against rocking piston, winter aeration and dissolved oxygen.
- Pressure filters and bead filters: sizing, maintenance, and when to move up to a drum filter.
- Rotary drum filters: drum against bead against sieve, gravity or pump fed, and micron screens.
- Bottom drains: aerated or standard, sizing, settlement chambers and retrofitting.
- UV sterilizers and clarifiers: the difference, how to size one, and where it goes.
Still not sure?
Call or text us on (206) 350-7580, or send us your numbers. We size ponds every day, and we would rather you asked than guessed.