About KoiPondCalculator.com

Why This Site Exists

A backyard pond runs on numbers. How many gallons does it actually hold? What size liner do you need, with the right overlap? How big a pump keeps the water turning over and the waterfall flowing? How many koi can it carry before the bioload outruns your filter? Get those right and a pond is a calm, beautiful, low-stress feature. Get them wrong and you end up with green water, struggling fish, and pumps that cannot keep up. Yet the answers are scattered across forums, contradictory advice, and rules of thumb that fall apart for koi, which grow large and produce a lot of waste.

We built KoiPondCalculator.com to put the math first. Our calculators turn your pond dimensions and goals into clear, equipment-ready answers in seconds, and our guides back those answers with practical, accurate advice for koi ponds, goldfish ponds, and water gardens.

What We Do

We are a calculator-first pond resource for keepers of every level, from a first small water garden to a serious koi pond. We research products, explain the why behind every number, and lay out your options so you can decide with confidence. Everything is written with one goal: accurate, practical help without the overwhelm.

• Calculators: pond volume, liner size, pump GPH, waterfall pump, koi stocking, UV clarifier, aeration, salt dosing, and cost
• Pond fish: koi, goldfish, and pond fish care, with size, water needs, and stocking
• Gear reviews: pumps, filters, UV clarifiers, liners, aerators, and netting, sized to your pond
• Water and care: the nitrogen cycle, new ponds, algae, parameters, and seasonal maintenance
• Reference charts: bookmark-worthy tables for volumes, liner sizes, pump turnover, and stocking
• Troubleshooting: clear fixes for green water, string algae, sick koi, and pump problems

How We Make Money

We are transparent about this. KoiPondCalculator.com earns money through the Amazon Associates program. When we recommend a product and you buy it through our link, we earn a small commission at no extra cost to you.

This keeps the calculators and guides free. We only recommend gear we believe is genuinely good for your pond and your fish, and we will never push the undersized pumps or weak filters that set new pond owners up to fail.

What We Are Not

We are not veterinarians, and our calculators are planning tools, not guarantees. Every pond is different. Nothing here is a substitute for professional advice on a sick fish.

If a koi or goldfish is ill, injured, or behaving abnormally, test your water first, then reach out to a knowledgeable koi or pond specialist or an aquatic veterinarian. We are here for the planning and everyday-care decisions that happen alongside that help.

Our Approach

Warm, practical, accurate, and honest. A well-built pond is one of the most rewarding things you can add to a backyard, and our job is to help you get the numbers and the care right so you can spend more time enjoying the water and the fish, and less time fighting problems.