Koi Pond Calculator: every number for a thriving pond
A 14 x 10 ft pond with a 2.5 ft average depth holds about 2,600 gallons, needs a 2,600 GPH pump, a 26 W UV clarifier and a 21 x 17 ft liner, and safely carries about 10 adult koi at 250 gallons each.
Enter your dimensions once and the 11 free calculators size the rest: pond volume, liner, pump, filter sizing, UV, aeration, koi stocking density, salt dosing and feeding amounts. Updated 2026.
Length
14 ft
Width
10 ft
Avg depth
2.5 ft
2,600 gallons
9,840 L · liner 21 × 17 ft
Most-used calculators
Tap a tool, enter your numbers, get an answer plus the gear that fits.
Pond Volume
Gallons & liters from your dimensions.
Koi Stocking Density
How many koi per gallon your pond can hold.
Pump Size (GPH)
Right pump flow for healthy turnover.
Pond Liner Size
Liner + underlayment with overlap.
Waterfall Pump
GPH for your spillway and head.
UV Clarifier Size
Beat green water with the right UV.
Pond Salt Dosing
Pounds of salt for 0.1%, 0.3% or 0.5%.
Pond Aeration
Diffusers and pump size for your depth.
Koi Feeding Chart
How much and how often by water temperature.
Top guides and gear picks
The pages pond keepers use most once the numbers are in.
Best Pond Pumps
Sized by GPH turnover, from 500 to 5,000+ gallons.
Best Pressure Filters
Filter sizing for koi loads, with UV built in.
Best Pond UV Clarifiers
About 10 watts per 1,000 gallons to clear green water.
Best Koi Food
Growth, color and wheat germ formulas by season.
Koi Growth Chart
Expected size by age so you plan for full-grown fish.
Overwintering Koi
Depth, de-icers and when to stop feeding.
Explore the whole hub
Calculators
11 free tools to size your pond and gear.
Explore → 🐠Pond Fish & Koi
Care, size, and stocking by species.
Explore → ⭐Gear Reviews
Pumps, filters, UV, liners, aerators, and more.
Explore → 💧Water & Care
Cycling, algae, parameters, and seasons.
Explore → 📊Reference Charts
Quick-look tables you can bookmark.
Explore → 🛟Troubleshooting
Fix green water, string algae, sick koi.
Explore → 🛒Pond Setups
Tiered shopping lists from starter to premium.
Explore →Sized to real equipment
Our calculators do not just give a number, they translate it into the pump GPH, UV wattage, liner size, and gear that actually fits your pond.
Koi ponds and water gardens
From a first small water garden to a serious koi pond, the tools and guides cover building, stocking, and year-round care.
No fluff, no fear-mongering
Clear, practical advice grounded in how pond keeping actually works, so you can make confident decisions fast.
The Koi Pond Care Planner
11 fill-in worksheets covering the build through year-round care, plus a companion spreadsheet, in one printable kit that keeps your pond healthy all year.
Get the Planner for $39Are you a pond or koi brand?
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