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Convert between tonnes, bulk bags, and small bags

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MOT Type 1 quantity with compaction allowance

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Calculator pre-set for 50mm driveway depth

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Calculator pre-set for 30mm path depth

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Calculator pre-set for 40mm patio depth

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Calculator pre-set for decorative borders

How Much Gravel?

Formula, worked examples, and depth guide

Driveway Cost Guide

Full 2026 cost breakdown — DIY vs professional

Gravel vs Alternatives

Gravel vs resin, tarmac, block paving, concrete

Planning Permission

The 5m² rule, SuDS 2025 changes, dropped kerbs

Best Gravel Types

Angular vs rounded, sizes, colours, and prices

How to Lay Gravel

Step-by-step from excavation to finished surface

Stop Gravel Spreading

7 proven containment methods

Gravel on a Slope

Gradient limits and retention techniques

Maintenance Guide

Seasonal upkeep, weed control, and top-ups

Cat-Proof Gravel

Stone selection and deterrents that work

Gravel vs Bark Mulch

Cost, lifespan, and which suits your borders

Wheelchair Access

Gravel grids and accessible surface design

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How Many Bags in a Ton?

One tonne (1,000kg) equals 40 × 25kg bags or 50 × 20kg bags. Use the converter below for any weight and every bag size used by UK suppliers — from 10kg handy bags to 850kg bulk bags.

Bags Needed

50x 20kg

Total Weight

1,000kg

Surplus

0kg

All Bag Options

Quick Reference: Tonnes to Bags

At a glance — how many bags of each size make up common order weights.

Weight10kg bags20kg bags25kg bagsBulk bags (850kg)Tonne bags
250 kg25131011
500 kg50252011
1 tonne100504021
2 tonnes2001008032
5 tonnes50025020065

Worked Examples

Ordering for a Path

You need 470kg of pea gravel and want to order in 20kg bags.

  • Bags needed: 470 ÷ 20 = 23.5 → round up to 24 bags
  • Total delivered: 24 × 20 = 480 kg
  • Surplus: 480 − 470 = 10 kg spare

Bulk vs Small Bags

You need 1.8 tonnes of slate gravel. Compare ordering options.

  • As 20kg bags: 1,800 ÷ 20 = 90 bags
  • As bulk bags (850kg): 1,800 ÷ 850 = 2.1 → 3 bags (2,550 kg)
  • As tonne bags: 1,800 ÷ 1,000 = 1.8 → 2 bags (2,000 kg)

Two tonne bags gives 200kg surplus — useful for future top-ups.

Choosing the Right Bag Size

For small projects under 100kg, individual 10\u201320kg bags are practical and easy to move by hand. For anything above that, ordering larger quantities (200kg, 500kg, or 1000kg) is far more economical. Suppliers like Stones4Gardens, offer both options with nationwide delivery.

Why Round Up?

We always round up to the next whole bag. Gravel settles, gets displaced during spreading, and some is inevitably lost in transit. Having a small surplus is far cheaper than a second delivery to make up the shortfall. The surplus shown in the results tells you exactly how much spare material each option gives you.

Need to Calculate from Measurements?

If you have the area dimensions rather than a weight, our main calculator works out the tonnage for you.

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Frequently Asked Questions

How many 25kg bags in a ton?
There are exactly 40 bags of 25kg in one tonne (1,000kg). The 25kg bag is the standard size for aggregates at UK builders' merchants, so for a full tonne you'd order 40 bags — though a single bulk bag is usually far cheaper.
How many 20kg bags in a tonne of gravel?
There are exactly 50 bags of 20kg in one tonne (1,000kg). In practice, you may need to round up to account for spillage or uneven spreading.
How many 15kg bags make a ton?
You need 67 bags of 15kg to make up a tonne (66.7 rounded up). At that quantity a bulk bag is much better value and saves a lot of lifting.
How many 40kg and 50kg bags in a tonne?
25 bags of 40kg make one tonne, and 20 bags of 50kg make one tonne. 50kg bags are less common in the UK because they exceed the recommended one-person lifting weight.
How many 25kg bags in a bulk bag?
A standard 850kg bulk bag holds the equivalent of 34 × 25kg bags. A full tonne (1,000kg) bag equals 40 × 25kg bags. Check which size your supplier uses — both are sold as 'bulk bags'.
How many 20kg bags make 1000kg?
Exactly 50 bags of 20kg make 1000kg (1 tonne). Ordering larger quantities like 500kg or 1000kg is significantly cheaper per kilogram than buying individual small bags.
What order sizes are available for gravel?
Common order sizes range from 10kg and 20kg bags for small projects, through 100kg and 200kg for medium areas, up to 500kg and 1000kg for larger projects like driveways and patios. Larger orders offer much better value per kilogram.
How many 10kg bags make a tonne?
Exactly 100 bags of 10kg make one tonne (1,000kg). However, for this quantity, ordering bulk bags is far more cost-effective — a single 1,000kg bag replaces 100 small bags.
How heavy is a bulk bag of gravel?
Most bulk bags contain either 850kg or 1,000kg. The 850kg 'jumbo bag' is the industry standard, though many suppliers also offer full tonne (1,000kg) bags. Always check the exact weight with your supplier.
How many tonnes do I need for a driveway?
A typical single-car driveway (5m × 3m) at 50mm depth needs about 1.1 tonnes of gravel. A double driveway (10m × 3m) at the same depth would need around 2.3 tonnes. Use our main calculator for an exact figure.
What's the difference between a tonne and a metric ton?
They're the same thing — both equal 1,000kg. In the UK, we use 'tonne' (metric) rather than the US 'ton' (short ton = 907kg or long ton = 1,016kg). All weights on this site use metric tonnes.
Is it better to order slightly more than I need?
Yes — we recommend ordering 5–10% extra. Gravel settles after laying, some is lost during spreading, and having to arrange a second delivery for a small shortfall is expensive. The surplus shown in our converter helps you plan for this.

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Gravel Depth Guide

Recommended depths for every project type and stone size

Bag to m² Converter

Work out how much area your bags of gravel will cover

Preview different gravel styles with the Stone Visualiser or shop aggregates at Stones4Gardens.