Pond Volume Calculator

Pond Volume for Pumps and Fish

Pond volume determines three critical things: pump size, filter capacity, and fish stocking limits. Undersize any of these and you'll have water quality problems — algae, murky water, or stressed fish. The calculator gives you gallons, which is the unit used for all pond equipment sizing and fish stocking recommendations.

A koi pond needs significantly more volume than a garden pond. The minimum recommended size for koi is 1,000 gallons — and serious koi keepers recommend 250 gallons per adult fish. A 6-foot koi can live 30+ years, so build bigger than you think you'll need. Garden ponds with just plants and small goldfish can be much smaller.

The Bottom Line

Free pond volume calculator. Gallons for garden ponds, koi ponds, and water features. Use this calculator to get an accurate estimate before purchasing materials or requesting contractor quotes. Accurate measurements save money and prevent project delays.