What this calculator works out
This calculator converts an estimated number of rubble or garden bags into a rough cubic yard figure and recommends a skip size, adjusting the advice when the waste is mostly heavy material.
Skips are sold by volume and limited by weight. For heavy waste those two constraints pull in opposite directions, which is why the recommendation changes rather than simply getting bigger.
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Before you order
- Ten builder's bags is roughly a cubic yard. Estimating in bags is easier than estimating in yards, which is why the tool works that way.
- Heavy waste — soil, rubble, hardcore, tiles — hits the weight limit long before the volume limit. Skip firms often refuse to lift an overloaded skip.
- A skip on a public road needs a permit from the council, arranged by the skip company, plus lights and markings.
- Some materials cannot go in a mixed skip at all, and putting them in usually attracts a charge.
A 6-yard skip filled with rubble can weigh more than the vehicle is licensed to lift, so skip firms commonly supply smaller skips for heavy waste and collect more often. Filling a large skip with soil and expecting it to be taken away is a common and expensive misunderstanding.
How this calculator works
Bags to yards, then a size band:
Cubic yards ≈ bags ÷ 10, rounded up
Up to 2 yards — mini skip
Up to 4 — midi skip
Up to 6 — builder's skip
Up to 8 — large builder's skip
Above 8 — 12-yard or larger
Heavy waste above 8 yards is split into multiple smaller loads insteadThe larger skip sizes are designed for bulky light waste — house clearances, packaging, garden material. They are not intended to be filled with rubble, and the recommendation reflects that rather than simply scaling with volume.
Worked example: 40 bags
Using the default figures — 40 bags of mixed waste, not mostly heavy:
- Rough capacity: 40 ÷ 10 = 4 cubic yards
- Recommended: 4-yard midi skip
Change the waste to mostly heavy and the same volume still fits a midi skip, but the weight becomes the binding constraint — 4 cubic yards of soil is roughly 5 tonnes, which is beyond what many midi skips are permitted to carry. In that situation two smaller loads, or a grab lorry, is usually both cheaper and actually possible.
Common mistakes
- Ordering by volume alone for heavy waste. Weight limits bind first.
- Overfilling above the rim. Skips must be level-loaded to be legally transported.
- Putting prohibited items in. Fridges, tyres, plasterboard, paint, chemicals and electricals usually need separate disposal.
- Forgetting the permit for a road placement. It takes days to arrange and the fine for going without is not small.
- Underestimating. A second skip costs far more than one size larger.
Frequently asked questions
Do I need a permit?
If the skip stands on a public road, verge or pavement, yes — a permit from the local council, normally arranged by the skip company, plus cones, lights and reflective markings. On your own driveway or land, no permit is needed. Permits take a few working days, so order early.
What cannot go in a skip?
Typically fridges and freezers, tyres, asbestos, paint, solvents, oil, batteries, gas cylinders, medical waste and electrical items. Plasterboard is usually excluded from mixed skips because it must be disposed of separately, though many firms supply a separate bag for it. Rules vary between companies, so ask.
Should I hire a skip or use the tip?
For a small amount, the household waste recycling centre is free and often quicker. For anything more than a few car loads, or heavy material, a skip usually wins on time and effort. Some councils restrict van and trailer access to tips, which pushes larger jobs towards a skip regardless.
What about a grab lorry?
For soil, rubble and hardcore, a grab lorry is frequently cheaper than skips because it carries far more weight and loads directly from a heap. It needs vehicle access and somewhere to pile the material within reach of the arm. For a large excavation it is almost always the better option.
Is what I enter stored?
No. Estimates are processed in your browser and never transmitted or retained.
Related tools
References
- GOV.UK — waste carrier duty of care, skip permits and household waste rules
- Health and Safety Executive — safe loading and manual handling of construction waste
Sources are checked at publication and can change — how I choose and check references.