How do I work out how many litres are in a pool?

Multiply the water area by the average depth, then by 1000. Average depth is (shallow end + deep end) ÷ 2. An 8 × 4 m pool from 1.0 m to 1.8 m deep is 32 × 1.4 = 44.8 m³, or 44,800 litres.

What about kidney-shaped pools?

Choose Freeform and enter the water area and edge length measured off the plan. You'll see 0.45 × (A + B) × length quoted online, but it isn't in any standard or manufacturer guide, and calculators don't even agree on the number, so we don't use it.

How much bigger do I dig than the pool?

It depends on the pool. A Leisure Pools fibreglass manual marks the excavation about 100 mm outside the pool edge and at least 100 mm deeper for the bedding layer. Firth's guide for block pools says about 300 mm larger all round. For concrete pools, use your engineer's drawings.

Why is the spoil more than the hole?

Dug soil loosens up. The Caterpillar Performance Handbook gives natural clay a load factor of 0.82, so a cubic metre in the ground becomes about 1.22 m³ in the truck. Topsoil and sandstone swell more, sand less. Site tests give the exact figure.

What are the pool fence rules?

Under AS 1926.1 as summarised by QBCC and SPASA, a pool barrier must be at least 1200 mm high, with no more than 100 mm under it or between verticals, a 900 mm non-climbable zone, and a self-closing gate with the latch at least 1500 mm up. Rules vary by state, so check your regulator.

Free calculator

Pool calculator

Pool volume in litres = water area × average depth × 1000, where average depth = (shallow + deep) ÷ 2. An 8 × 4 m pool from 1.0 to 1.8 m deep holds about 44,800 litres. Dig volume is the pool plus the over-dig and the extra depth under the floor.

Your job

Pool shape

Length

Width

Shallow end depth

Deep end depth

Uses the average of the two depths, which assumes an even slope. Hopper floors hold more.

Excavation and spoil

Over-dig each side

Extra dig below floor

Fibreglass: about 100 mm outside the pool edge and at least 100 mm deeper for bedding (Leisure Pools manual). Use your pool maker's dig sheet if it differs.

Soil

Truck

Soil swell and weight from the Caterpillar handbook (tests give exact values). Truck weights are NSW EPA deemed loads, not legal payloads.

Coping and paving

Coping piece length

Or your coping length

Wastage allowance5%

Allow for cuts at corners and curves. Curved and freeform pools need more.

Paving surround width (0 for none)

Pool safety fence

Fence run

Panel centres

Gates

Gate width

Defaults: a 2400 mm aluminium panel on about 2455 mm centres with a 970 mm gate. Glass and other panels: type your supplier's sizes.

At least 1200 mm high
No more than 100 mm under it or between verticals
900 mm non-climbable zone outside
Gate latch at least 1500 mm up, self-closing
AS 1926.1 as summarised by QBCC and SPASA. Rules differ by state: check your regulator.

Plan to scale; the section exaggerates depth three times.

Water

44,800litres

44.8 m³ at 1.40 m average depth

Dig (bank)

51.7m³

34.4 m² × 1.50 m deep

Spoil to cart

63.0m³ loose

104.4 t, about 10 truck loads

Coping

63pieces

25.2 m at 400 mm each

Paving surround

28.0m²

1.00 m wide

Pool fence

12panels

14 posts, 1 gate

The working, with your numbers

1. Water area8 × 4= 32.00 m²
2. Water volume32.00 × (1 + 1.8) ÷ 2= 44,800 L
3. Dig footprintarea + edge × 0.1 + corners= 34.44 m²
4. Dig volume34.44 × (1.40 + 0.1)= 51.7 m³
5. Spoil51.7 ÷ 0.82 load factor; × 2020 kg/m³= 63.0 m³, 104.4 t
6. Truck loads104.4 t ÷ 10.97 t= 10
7. Coping24.00 m × 1.05 ÷ 0.4= 63 pieces

Typed those measurements in by hand?MetreMate measures them straight off your PDF plans. Free to start.

The formula, in plain words

1Water area: rectangle = length × width; round = π ÷ 4 × diameter²; oval = π ÷ 4 × length × width; rounded ends = length × width − (1 − π ÷ 4) × width². Freeform and kidney pools use the area measured off the plan.
2Litres = water area × (shallow + deep) ÷ 2 × 1000. That assumes an even slope between the ends.
3Dig footprint = water area + edge length × over-dig + corners. Dig volume = footprint × (average depth + extra dig below the floor).
4Spoil to cart (loose) = dig volume ÷ the soil's load factor, and weight = dig volume × the soil's bank density, from the Caterpillar Performance Handbook.
5Truck loads = weight ÷ tonnes per load, rounded up. Presets are NSW EPA deemed loads for soil: 5.58, 10.97 and 15 t.
6Coping pieces = edge length × (1 + wastage) ÷ piece length, rounded up. Paving surround = edge × width + 4 × width² for square corners, or + π × width² for curved pools.
7Pool fence panels = (fence run − gate openings) ÷ panel centres, rounded up. Posts = panels + 1, plus one per gate.

Worked example

An 8 × 4 m fibreglass pool, 1.0 m to 1.8 m deep, dug in natural clay with 100 mm over-dig and 100 mm under the floor, carted in tandem trucks. 400 mm coping with 5% wastage, a 1 m paved surround and a 30 m aluminium pool fence with one gate.

1.Water: 8 × 4 = 32 m² × (1.0 + 1.8) ÷ 2 = 44.8 m³, which is 44,800 litres.
2.Dig: (8.2 × 4.2) = 34.44 m² × (1.4 + 0.1) = 51.66 m³ in the ground.
3.Spoil: 51.66 ÷ 0.82 = 63.0 m³ loose; 51.66 × 2.02 t/m³ = 104.4 t, which is 104.4 ÷ 10.97 = 9.5, so 10 tandem loads.
4.Coping: 24 m edge × 1.05 ÷ 0.4 = 63 pieces. Paving: 24 × 1 + 4 × 1² = 28 m².
5.Fence: (30 − 0.97) ÷ 2.455 = 11.8, so 12 panels and 12 + 1 + 1 = 14 posts.

Answer: 44,800 litres; 51.66 m³ to dig, 10 tandem loads of spoil; 63 coping pieces; 28 m² of paving; 12 fence panels and 14 posts.

How to measure it

Measure the water surface: length and width, or the diameter for a round pool. For a kidney or freeform pool, trace the outline on the plan to get its area and edge length.
Take the shallow and deep end depths from the pool plans or the manufacturer's spec sheet.
Use the pool maker's or engineer's dig sheet for over-dig and the depth under the floor if you have it.
Measure the pool fence run around the pool area, and count the gates.

Where the numbers come from

Every default in the calculator is a number a supplier or manufacturer publishes. We list the source next to it so you can check.

What	Value	Source
Fibreglass: excavation line about 100 mm outside the pool edge	100 mm each side	Leisure Pools fibreglass pool installation manual (used with AS/NZS 1839) (checked 2026-09-30)
Fibreglass: dig at least 100 mm deeper for the bedding layer	100 mm	Leisure Pools fibreglass pool installation manual (used with AS/NZS 1839) (checked 2026-09-30)
Masonry block pool: excavation about 300 mm larger all round	300 mm all round	Firth FIR0744 Masonry Swimming Pools (checked 2026-09-30)
Soil swell: loose = bank ÷ load factor (clay 0.82, earth 0.80, sand 0.89, topsoil 0.70, sandstone 0.60); tests must be made for exact values	0.82 load factor (clay)	Caterpillar Performance Handbook, Edition 50 (2021), p.25-1 and p.27-5 (checked 2026-09-30)
Deemed loads for soil: 5.58 t single axle, 10.97 t tandem, 15 t semi (levy weights, check your truck's payload)	10.97 t per tandem load	NSW EPA Waste Levy Guidelines (July 2026), Table 4 p.13 (checked 2026-09-30)
Sharknose coping paver, 400 x 400 x 40	400 mm	Adbri Masonry 400 x 400 x 40 sharknose paver (Bunnings listing) (checked 2026-09-30)
Travertine bullnose coping, 610 x 406 x 30 (one piece spans 0.61 m)	610 mm	Graystone travertine bullnose coping 610 x 406 x 30 (checked 2026-09-30)
Pool barrier at least 1200 mm high from finished ground level	1,200 mm	QBCC Pool fences (AS 1926.1-2012 as summarised) (checked 2026-09-30)
No more than 100 mm under the barrier or between verticals	100 mm	QBCC Pool fences (AS 1926.1-2012 as summarised) (checked 2026-09-30)
Non-climbable zone of 900 mm on the outside of the barrier	900 mm	SPASA pool fencing rules (checked 2026-09-30)
Gate latch release at least 1500 mm above the ground	1,500 mm	QBCC Gates, latches and hinges (checked 2026-09-30)
Aluminium 2400 x 1200 panel on about 2455 to 2460 mm post centres	2,455 mm	Oxworks aluminium pool fencing (checked 2026-09-30)
Aluminium pool gate 970 x 1200	970 mm	Oxworks aluminium pool fencing (checked 2026-09-30)

Manufacturers named here are the source of the number, not a recommendation. Confirm quantities with your supplier.

Frequently asked questions

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