Last checked
May 12, 2026
We checked the page logic, support notes, and related links on this page.
Type 1 sub-base tool
MOT Type 1 Calculator
Estimate MOT Type 1 volume, tonnage, bulk-bag buying quantities, and rough delivery needs for driveways, paths, and compacted sub-base layers.
Volume + tonnes + unitsWaste-aware resultBuying checks
How to use it
Planning before buying
Use this calculator for a planning check, then confirm the final order or quote against live product data and site conditions.
Why trust it
See how the site is maintained
Read the calculator methodology and editorial policy for the standards behind these pages.
Planning summary
Quick answer
Enter base area and compacted depth, add waste, then convert the adjusted volume into tonnes, tons, bulk bags, or loose supply.
Planning summary
Watch most
The common misses are underestimating compacted depth, forgetting edge thickening or levelling corrections, and assuming the loose-delivered quantity matches the installed layer without checking compaction.
Planning summary
Best next move
Check the compacted target depth against the actual build-up first, because edge thickening, turning areas, and weak formation can use more Type 1 than the neat footprint suggests.
Recently used calculators
Pick up from the calculators you used recently on this device.
Quote-ready brief
Use these actions to turn the live calculator result into a cleaner request for builders, suppliers, or merchants.
Run the calculator, then use these actions to prepare the estimate for a real quote request.
Need help deciding what to ask for? Read the quote checklist or contact the team at hello@buildcostlab.com.
Practical checks before you buy
These notes are where BuildCostLab goes beyond a generic calculator result by surfacing the assumptions, buying traps, and next decisions that usually move the real order.
Global terminology and buying units
Use this page across English-speaking markets by matching the local material name, unit, and buying format.
Also known as
Type 1 sub-base calculatorroad base calculatorcrushed rock sub-base calculator
Search intent
mot type 1 calculatortype 1 calculatorsub base calculator
Quick answer
Enter base area and compacted depth, add waste, then convert the adjusted volume into tonnes, tons, bulk bags, or loose supply.
Regional buying note
MOT Type 1 is UK-specific wording. In other markets the closest buying intent may be road base, crushed rock sub-base, or compacted aggregate base.
Unit examples
Use compacted depth in mm, inches, metres, or feet, then convert to cubic metres, cubic yards, tonnes, tons, or bulk bags.
What this estimate includes
The measured volume, waste-adjusted buying quantity, density or unit-size conversion, and a rough material spend when a price is entered.
What it may not include
Unexpected excavation differences, compaction behaviour, haulage constraints, and local delivery charges unless you add them separately.
Key assumptions
MOT Type 1 estimates work best when the footprint, compacted depth, edge detail, and the intended sub-base build-up are clear before the order is placed.
Worked example
Example: a 6m by 3m driveway base at 120mm compacted depth gives 2.16m3 before waste. Add 10 percent and the planning quantity becomes 2.376m3. At roughly 1.8 tonnes per m3, that is about 4.28 tonnes, so five 0.85-tonne bulk bags is the safer planning order.
How this estimate is worked out
We multiply length by width by depth, add the waste allowance, then convert the adjusted volume into tonnes or whole buying units using the stated density and delivery format.
What assumptions sit underneath it
MOT Type 1 estimates work best when the footprint, compacted depth, edge detail, and the intended sub-base build-up are clear before the order is placed.
How rounding is handled
Because bulk materials are bought by bag, bulk bag, tonne, or loose load, the final answer rounds to a real buying quantity rather than stopping at the theoretical trench or base volume.
What changes the result most
Compacted depth, density, edge thickening, and whether the area needs level correction usually move the Type 1 order fastest.
Where people under-order
Drive edges, weak spots, and turning areas often use more Type 1 than the neat footprint suggests once the real build-up is checked.
Practical buying checks
Compare bulk bags against loose tonnes, confirm the specified Type 1 grade, and check whether membrane, bedding, and drainage layers are being priced separately.
Quote-ready checklist
Use these prompts when you want to turn the estimate into a clearer builder, installer, or merchant request.
- State the measured area, target depth, and whether the depth is compacted or loose-delivered.
- Ask how the material will be supplied: bags, bulk bags, loose load, or ready-mix route where relevant.
- Flag any access, storage, delivery, or waste-removal limits before the first quote is treated as final.
Explore this project hub
Open the full Aggregate and Base Estimating project hub to move from quick estimate to deeper guidance.
Related calculators for the same base-build job
Use these linked tools when the Type 1 estimate also depends on sub-base build-up, membrane separation, hardcore below, or nearby drainage trench quantities.
Sub-Base Calculator
Estimate sub-base volume, tonnes, and delivered quantity for paving, patios, paths, and driveway foundations before you order.
Hardcore Calculator
Estimate hardcore volume, tonnes, and bulk-bag buying quantities for driveways, patio bases, shed bases, and general fill work.
Geotextile Membrane Calculator
Estimate geotextile membrane rolls, overlaps, and covered area for driveways, french drains, trenches, and separating aggregate layers.
Pipe Bedding Calculator
Estimate pipe bedding volume, tonnes, and bulk-bag buying quantities for drainage trenches before you order sand or gravel.
Keep planning the same job
These are the strongest next calculators when this estimate is only one part of the buying or quote-prep workflow.
Next stepAggregates
Sub-Base Calculator
Estimate sub-base volume, tonnes, and delivered quantity for paving, patios, paths, and driveway foundations before you order.
Next stepAggregates
Hardcore Calculator
Estimate hardcore volume, tonnes, and bulk-bag buying quantities for driveways, patio bases, shed bases, and general fill work.
Next stepDrainage
Geotextile Membrane Calculator
Estimate geotextile membrane rolls, overlaps, and covered area for driveways, french drains, trenches, and separating aggregate layers.
Next stepOutdoor surfacing
Paving Calculator
Estimate patio slabs, pavers, coverage, cut waste, and rough material cost for patios, paths, and paved garden areas.
Quick answers
These answers are designed to resolve the last practical buying questions people usually have after running the calculator.
How do I use the MOT Type 1 Calculator?
Enter the footprint, compacted Type 1 depth, and a realistic waste allowance, then compare the result as cubic metres, tonnes, and buying units before you order.
What changes the MOT Type 1 Calculator estimate most?
The biggest drivers are compacted depth, density, edge thickening, level corrections, and whether the supplier prices by bulk bag or loose tonne.
Should I round the result up?
Usually yes. Compaction, weak spots, and merchant minimums often justify a modest overage rather than landing exactly on the paper total.
Use this estimate in a quote request
Copy the estimate, add your own notes, and send the same scope to each builder or supplier so the quotes are easier to compare.
- Confirm what the quote should include: materials only, labour only, or both.
- State access, finish level, timing, and any unknowns clearly.
- Ask each supplier or installer to price the same scope and exclusions.
You can also open the wider Aggregate and Base Estimating project hub if the quote depends on more than one material.