What does the Pond Volume Calculator do?

Calculate pond volume in litres, pump size and liner dimensions for rectangle, circle or oval ponds. All calculations are performed in your browser using official UK rates and thresholds.

Does this include delivery costs?

This calculator estimates material quantities and approximate costs. Delivery charges vary by supplier, quantity and location. Bulk orders often qualify for free or reduced delivery.

When is the best time for this project?

Timing depends on the specific project. Generally, spring and autumn are ideal for lawn and planting work, while hard landscaping can be done year-round in dry conditions.

Pond Volume Calculator

Calculate pond volume in litres, pump size and liner dimensions for rectangle, circle or oval ponds.

Last updated: April 2026 · Source: RHS — Ponds

Length (m)

Width (m)

Depth (m)

Volume

3600 litres

Gallons

792

Pump Size

3600 LPH

Liner Size

4.8 x 3.8m

Disclaimer

This calculator is provided for informational purposes only and should not be considered as financial or tax advice. All calculations are performed locally in your browser — no personal data is collected or sent to our servers. Rates and thresholds are sourced from HMRC and GOV.UK and are updated for the current tax year. Always verify results with HMRC or consult a qualified professional before making financial decisions.

How It Works

Pond volume is calculated differently depending on shape. For rectangular ponds: length × width × average depth. For circular ponds: π × radius² × average depth. Irregular ponds are estimated by dividing into sections. Multiply the result in cubic metres by 1,000 to convert to litres. Most garden ponds hold 500–5,000 litres.

Knowing your pond volume is essential for fish stocking (the general rule is 50–75 litres per centimetre of fish), pump sizing (the pump should circulate the full volume at least once every 1–2 hours), filter selection and dosing treatments (algaecides, dechlorinators and fish medications are all dosed per litre).

Enter the pond dimensions and shape. The calculator shows volume in litres and cubic metres, recommended pump flow rate, and stocking capacity. For ponds with shelves or varying depths, use the average depth or calculate each section separately.

Example: Kidney-shaped pond, approx. 3 m × 2 m, average depth 0.8 m

Approximate as oval: π × 1.5 × 1.0 × 0.8 = 3.77 m³
Volume: 3,770 litres
Pump flow rate: 3,770 ÷ 1.5 hours ≈ 2,500 litres/hour
Fish stocking: supports ~50–75 cm total fish length

Source: RHS — Ponds

Frequently Asked Questions

What does the Pond Volume Calculator do?: Calculate pond volume in litres, pump size and liner dimensions for rectangle, circle or oval ponds. All calculations are performed in your browser using official UK rates and thresholds.
Does this include delivery costs?: This calculator estimates material quantities and approximate costs. Delivery charges vary by supplier, quantity and location. Bulk orders often qualify for free or reduced delivery.
When is the best time for this project?: Timing depends on the specific project. Generally, spring and autumn are ideal for lawn and planting work, while hard landscaping can be done year-round in dry conditions.