Gravel Estimator
This gravel calculator finds the tonnes and tonne bags of gravel or Clause 804 you need in Ireland.
Measure your project
Your answer
That is 1.00 m³.
If you buy bags
If you buy tonne bags
Power Aggregates says to use your supplier's own figure if it gives one.
Which costs less?
This price is for picking it up yourself. Add a delivery fee in "Change prices" if they bring it.
20 mm gravel: €70 a tonne bag, the middle of 5 Irish sellers (Oct 2026). 25 kg bags: €5.25, from only 2 sellers. Prices include 23% VAT where the seller says so. Treat them as a rough guide.
Quick answers
- A 5 × 4 m path, 50 mm deep
- About 1.6 tonnes of 20 mm gravel. That is 2 tonne bags, or 64 bags of 25 kg.
- Weight of 1 m³
- About 1.6 tonnes for 20 mm gravel (Power Aggregates). For packed-down Clause 804 we use about 2 tonnes, worked out from Roadstone's cover figure.
- What a tonne covers
- About 12.5 m² at 50 mm deep, or 25 m² at 25 mm, by our sum. Irish sellers' figures run a little either side.
- Tonne bags
- Irish quarries and most merchants sell them as about 1,000 kg. Power Aggregates says a standard bulk bag holds 800–850 kg, so check the label.
How to work it out
- Measure the length and width in metres. Multiply them to get the area in m².
- Pick the depth in mm. Divide it by 1,000 to get metres.
- Area × depth = the volume of gravel in m³.
- Multiply by 1.6 to get tonnes. For packed-down Clause 804, multiply by 2 (worked out from Roadstone's cover figure).
- Round the tonnes up to whole tonne bags. Tonnes × 40 = 25 kg bags.
5 × 4 × 0.05 = 1 m³
1 × 1.6 = 1.60 tonnes
1.60 tonnes → round up → 2 tonne bags
Gravel for common sizes
| Size | Tonnes, 25 mm | Bags | Tonnes, 50 mm | Bags |
|---|---|---|---|---|
| 3 × 1 m | 0.12 | 1 | 0.24 | 1 |
| 5 × 1 m | 0.20 | 1 | 0.40 | 1 |
| 3 × 3 m | 0.36 | 1 | 0.72 | 1 |
| 5 × 4 m | 0.80 | 1 | 1.60 | 2 |
| 10 × 3 m | 1.20 | 2 | 2.40 | 3 |
| 10 × 5 m | 2.00 | 2 | 4.00 | 4 |
Sizes as shown, nothing extra. Bags are tonne bags of 1,000 kg, rounded up.
What area does 1 tonne of gravel cover?
Our sum uses 1.6 tonnes per m³. Power Aggregates prints its own table for 20 mm gravel.
| Depth | Our sum | Power Aggregates says |
|---|---|---|
| 25 mm | 25 m² | 20 m² |
| 50 mm | 12.5 m² | 12 m² |
| 75 mm | 8.3 m² | 7–9 m² (rough estimate) |
| 100 mm | 6.3 m² | 5–7 m² (rough estimate) |
Why the answers differ
Power Aggregates gives 1.4–1.6 tonnes per m³ for decorative gravel. Crushed stone is heavier, at 1.75–1.8 tonnes.
At about 25 mm, Irish sellers give 20–30 m² a tonne. Howbert & Mays says 25–30 m² at 25–30 mm.
Clause 804: what it is and how much you need
Clause 804 is crushed rock for the base under a drive, path or patio. The name comes from Ireland's road-building spec (TII). The stones run from dust up to about 63 mm. Most of it is under 31.5 mm.
Roadstone now calls it UGM. Many merchants still sell it as "804" or "SR21 / 804".
How deep and how heavy
Roadstone says 150–300 mm of packed-down 804 suits most paving. The right depth depends on your soil and the load. Pack it to within 10–15 mm of the level you need.
We found no Irish seller that gives a weight for 804. Roadstone says a tonne covers about 10–12 m² at 50 mm. We use the heavy end of that: about 2 tonnes per m³ once packed. Wickes in the UK gives 2.08 tonnes for Type 1, a similar stone.
| Size | Tonnes, 150 mm | Bags | Tonnes, 300 mm | Bags |
|---|---|---|---|---|
| 3 × 2 m | 1.8 | 2 | 3.6 | 4 |
| 5 × 3 m | 4.5 | 5 | 9.0 | 9 |
| 10 × 3 m | 9.0 | 9 | 18.0 | 18 |
| 10 × 5 m | 15.0 | 15 | 30.0 | 30 |
Tonne bags, rounded up. For your own sizes, pick Clause 804 in the calculator.
Under a house floor
This page covers 804 under drives, paths and patios. Fill under a house floor is different. Roadstone says to ask for S.R. 21 Annex E fill. The slab page explains the layers. Check the docket says Annex E. Our concrete slab calculator covers floors. Check your local building rules or ask a builder or engineer.
How deep should gravel be?
- Beds and borders: 25–40 mm, says Power Aggregates.
- Paths and patios: 50 mm.
- Drive: 50 mm of gravel on 150 mm of sub-base, says B&Q Ireland. In Ireland that sub-base is Clause 804. Power Aggregates suggests 75–100 mm of gravel on a drive.
A 10 × 3 m gravel drive
Built the B&Q Ireland way, you dig out 200 mm in all.
| Layer | m³ | Tonnes | Tonne bags |
|---|---|---|---|
| Clause 804, 150 mm | 4.5 | 9.0 | 9 |
| 20 mm gravel, 50 mm | 1.5 | 2.4 | 3 |
For 1,000 kg bags. With 800–850 kg bags, the 804 takes 11–12 bags.
For a drive, check your local building rules or ask a builder or engineer.
Tonne bags, 25 kg bags and prices
A tonne bag holds about 1,000 kg, says Kilsaran. 40 small bags of 25 kg make a tonne.
Prices with 23% VAT, where the seller says so (Oct 2026):
- 20 mm gravel: €70 a tonne bag, the middle of 5 sellers (€66–€104).
- General gravel or batch gravel: €67.65, the middle of 11 sellers (€52.99–€79.95).
- Clause 804: €65.50, the middle of 4 sellers (€64.95–€75).
- 25 kg bags of gravel: €5.25, from only 2 sellers. So 40 of them cost about €210.
Revenue charges 23% VAT on sand and gravel.
Batch gravel is for concrete
Batch gravel is stone, grit and sand that you mix with cement, says Kenny Fuels. For concrete, use our concrete calculator.
Questions people ask
How much gravel do I need?
Multiply length × width × depth, all in metres, to get m³. Then m³ × 1.6 = tonnes. For example, 20 m² of path at 50 mm comes to about 1.6 tonnes.
How many square metres will a tonne of gravel cover?
By our sum at 1.6 tonnes per m³, about 12.5 m² at 50 mm and 25 m² at 25 mm. Power Aggregates' table says 12 m² and 20 m². Roadstone says 10 m² at 50 mm for its driveway pebble.
How much gravel per square metre?
Each m² takes about 40 kg at 25 mm and 80 kg at 50 mm. Kilsaran puts 3 bags of 25 kg on each m² at 40 mm.
How much gravel per cubic metre?
About 1.6 tonnes of 20 mm gravel. Power Aggregates gives 1.4–1.6 tonnes for decorative gravel. So one tonne fills about 0.63 m³.
How many wheelbarrows in a tonne of gravel?
About 14–15 half loads, or 7 full ones. We worked this out for a barrow of 85–90 litres filled to the brim. A full load weighs 136–144 kg.
How much Clause 804 do I need?
Work out the m³ with the depth after packing down. Then m³ × 2 = tonnes. We worked out the 2 from Roadstone's cover figure. At 150 mm deep, each m² takes about 0.3 tonnes.
How deep should a gravel driveway be?
B&Q Ireland lays 50 mm of gravel on 150 mm of packed-down sub-base (Clause 804 in Ireland). Power Aggregates suggests 75–100 mm of gravel. Check your local building rules or ask a builder or engineer.
How much is a tonne bag of gravel in Ireland?
About €70 for 20 mm gravel, the middle of 5 sellers, in October 2026. Clause 804 is about €65.50, from 4 sellers. Prices include 23% VAT where the seller says so.
Where our numbers come from
- Gravel cover per tonne: Power Aggregates, Cork (12 m² at 50 mm)
- Gravel weight: Wickes UK 20 mm gravel bulk bag (800 kg covers 20 m² at 25 mm)
- Driveway gravel cover: Roadstone Driveway Pebble (10 m² per tonne at 2 in)
- 20 mm gravel tonne bag: Howbert & Mays, Dublin (€70 inc VAT)
- Decorative gravel cover: Kilsaran (3 bags per m² at 40 mm)
- Clause 804: TII road spec, crushed rock 0/31.5 mm (2013)
- Sub-base: TII road spec UGM A and UGM B, 0/31.5 mm (2023)
- Clause 804: Roadstone page (now called UGM, 0–31.5 mm)
- Clause 804 depth: Roadstone guide (150–300 mm, packed down)
- Type 1 weight and price: Wickes 800 kg bag (checked Oct 2026)
- Hardcore under floors: S.R. 21 Annex E grades (Roadstone FAQ)
- Fill under floors: Roadstone granular fill and S.R. 21 grades
- Gravel driveway: B&Q Ireland guide (150 mm sub-base, 50 mm gravel)
- Batch gravel tonne bag: Kenny Fuels, Wexford (€65 inc VAT, 1,000 kg)
- Tonne bags: CoreBuild, Dublin (gravel, hardcore, sand €67.65 inc VAT)
- Tonne bag prices: the middle price from Irish sellers (Oct 2026)
- 25 kg gravel bag price: Woodie's and Goodwins (Oct 2026)
- Wheelbarrow sizes: B&Q Ireland (Walsall 85, 90 and 120 litres)
- VAT on sand and gravel in Ireland: standard rate (Revenue)
- Irish VAT rates: Revenue (23%, 13.5%, 9%)
Made by BuildersCount. Last checked 4 Oct 2026.
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