Pond Literage Calculator
Work out your pond literage in seconds. This pond literage calculator returns the total pond volume in litres (plus cubic metres and gallons) from the pond length, width, and average depth. Getting the literage right is the starting point for every medication, dechlorinator, and liquid fertilizer dose, and it drives pond pump and filter sizing. Works for backyard koi ponds, preformed shells, and large irregular natural ponds where you already know the surface area.
Pond Literage Formula
Pond volume in litres is surface area (square metres) times average depth (metres) times 1,000:
- Rectangular pond: Length (m) x Width (m) x Avg Depth (m) x 1,000 = litres
- Round pond: pi x Radius^2 x Avg Depth x 1,000
- Oval pond: pi x (Length/2) x (Width/2) x Avg Depth x 1,000
- Irregular pond: Measured Surface Area (sq m) x Avg Depth x 1,000
Average depth equals (shallow + deep) / 2 for ponds with sloped sides. For natural ponds, average depth is usually 40-60% of the maximum depth because the edges taper.
Typical Backyard Pond Literage
- Small patio pond 1.5 x 1 m at 0.5 m deep: about 750 L
- Medium pond 2 x 1.5 m at 0.75 m deep: about 2,250 L
- Koi pond 3 x 2 m at 0.9 m deep: about 5,400 L
- Large pond 4 x 3 m at 1.2 m deep: about 14,400 L
- Round pond 2 m diameter at 0.8 m: about 2,500 L
Why Pond Literage Matters
Every pond treatment bottle lists the dose as "per 1,000 litres" or "per 5,000 litres". Underdose and the treatment fails; overdose and you can kill the fish. Getting pond literage right is the single most useful number for keeping a healthy pond. It also sets the right pond pump size (turn the full volume over every 1-2 hours for koi, every 2-4 hours for goldfish), the right filter rating, and how much dechlorinator to use every time you top up.
Measuring an Irregular Pond
For odd-shaped ponds, measure the surface area first, then multiply by average depth. Three methods:
- Grid method: Stretch a tape across the pond at 1 m intervals, note each width, sum them, and multiply by 1 m to get area in sq m.
- Google Earth tool: Open satellite view, right-click around the perimeter, and Earth returns the enclosed area in square metres or square feet.
- Dye-and-timer method: If you know your pump flow rate in L/min, add food-grade dye and time how long it takes to cycle through; flow x time equals volume.
Fish Stocking by Pond Literage
The cautious koi-pond rule of thumb is 1 cm of fish body length per 30 litres of water. A 5,000 L pond supports about 165 cm of fish, which is roughly 4-5 adult koi (30-40 cm each), 15 goldfish (10 cm each), or a mix. More aggressive guides go to 1 cm per 10 L when you have heavy filtration and aeration; new ponds and hot-weather ponds should stick with the 1 cm per 30 L rule for safety.