Key numbers
- Formula: L × W (ft) × compacted depth (in) ÷ 12 ÷ 27 = yd³; yd³ × 1.9 = tons
- Density used: 3,800 lb/yd³ (1.9 t/yd³, about 2.25 t/m³), Ohio DOT's compacted crushed-stone conversion
- Per 100 ft² at 6 in: 1.85 yd³, 3.52 tons; at 4 in: 1.23 yd³, 2.35 tons
- Depth: UW–Madison's gravel road manual calls for at least 6 in of gravel; Oregon State Extension gives 4–6 in of base under pavers
- Sold by ton or yard: TxDOT Item 247 lets base be measured by the cubic yard in trucks or by the dry ton
On this page
How to use the Road Base Calculator
- 1Describe the areaChoose Rectangle (length × width), Circle (diameter) or Known area if you already have the square footage.
- 2Pick your unitsUse US (feet and inches) or Metric (meters and centimeters). Switching converts the numbers you typed, so the area stays the same.
- 3Enter the depthType how deep the road base, compacted (ohio dot 1.9 t/yd³) should be, 6 in is a common starting point for this job.
- 4Choose the materialPick road base, compacted (ohio dot 1.9 t/yd³), crusher run / road base or crushed stone (#57). Each uses its own weight per cubic yard to work out tons.
- 5Allow for settlingChoose the extra: none, 5%, 10% (the default) or 20% for a base you will compact.
- 6Read and price the resultsSee cubic yards, cubic feet, cubic meters, US tons and metric tonnes. Enter your supplier's price per ton for the total cost.
Results update as you type. Back to the calculator ↑
How much road base do I need?
Work out the compacted volume, then convert it to tons. Road base is placed loose and rolled down, so measure the finished, compacted depth you want and use a compacted density. That way the tons you order end up as the thickness you planned.
Volume (yd³) = length (ft) × width (ft) × compacted depth (in) ÷ 12 ÷ 27
Tons = volume (yd³) × 1.9 t/yd³ (or your supplier’s compacted figure)
Order = tons × (1 + extra % for edges and subgrade)
The 1.9 t/yd³ comes from Ohio DOT’s construction specifications. Its Item 617 conversion table, used to turn compacted aggregate quantities into pay tons, lists crushed stone at 3,800 lb per cubic yard. That is 140.7 lb/ft³, or about 2.25 tonnes per m³. Gravel, slag and recycled bases weigh differently, and so does one quarry’s limestone against another’s granite, so the calculator lets you type your supplier’s figure.
Worked example: 12 × 50 ft driveway, 6 in compacted base
- Volume: 12 × 50 × 6 ÷ 12 = 300 ft³ ÷ 27 = 11.11 yd³ (8.5 m³)
- Tons at 1.9 t/yd³: 11.11 × 1.9 = 21.11 tons (19.15 tonnes)
- With 10% extra: 12.22 yd³, about 23.22 tons (21.07 tonnes)
Loose stone in a truck weighs less per yard than compacted base, so a quarry quoting loose weight will sell fewer tons for the same yards. Ask your quarry which one its weight is.
How many tons of road base per cubic yard?
About 1.9 tons per compacted cubic yard is the figure this calculator uses, from Ohio DOT. Loose material straight off the truck weighs less per yard because it holds more air. You need more loose yards than compacted yards to build the same layer, but the tons stay the same: rolling squeezes air out, not stone.
That is why the density matters more than the name on the ticket. If your quarry quotes a weight per loose yard, either use that number and add a compaction allowance (ask them how much), or use a compacted figure and add only a small extra for waste. Using a loose density and no allowance is the most common way to come up short.
TxDOT’s flexible base specification (Item 247) shows how buyers are charged. A job can measure base by the cubic yard in vehicles of uniform capacity, by the ton of 2,000 lb dry weight as delivered, or by the cubic yard in the final stockpile. Ask which one your supplier uses before comparing quotes.
Road base by area and depth (table)
Tons at 1.9 t/yd³, including 10% extra. Read the row for your area and the column for your compacted depth.
| Area (ft) | 4 in | 6 in | 8 in | 10 in | 12 in |
|---|---|---|---|---|---|
| 10 × 10 | 1.36 yd³ · 2.58 t | 2.04 yd³ · 3.87 t | 2.72 yd³ · 5.16 t | 3.40 yd³ · 6.45 t | 4.07 yd³ · 7.74 t |
| 10 × 20 | 2.72 yd³ · 5.16 t | 4.07 yd³ · 7.74 t | 5.43 yd³ · 10.32 t | 6.79 yd³ · 12.90 t | 8.15 yd³ · 15.48 t |
| 12 × 24 | 3.91 yd³ · 7.43 t | 5.87 yd³ · 11.15 t | 7.82 yd³ · 14.86 t | 9.78 yd³ · 18.58 t | 11.73 yd³ · 22.29 t |
| 20 × 20 | 5.43 yd³ · 10.32 t | 8.15 yd³ · 15.48 t | 10.86 yd³ · 20.64 t | 13.58 yd³ · 25.80 t | 16.30 yd³ · 30.96 t |
| 16 × 40 | 8.69 yd³ · 16.51 t | 13.04 yd³ · 24.77 t | 17.38 yd³ · 33.03 t | 21.73 yd³ · 41.28 t | 26.07 yd³ · 49.54 t |
| 12 × 50 | 8.15 yd³ · 15.48 t | 12.22 yd³ · 23.22 t | 16.30 yd³ · 30.96 t | 20.37 yd³ · 38.70 t | 24.44 yd³ · 46.44 t |
| 24 × 60 | 19.56 yd³ · 37.16 t | 29.33 yd³ · 55.73 t | 39.11 yd³ · 74.31 t | 48.89 yd³ · 92.89 t | 58.67 yd³ · 111.47 t |
Per 100 ft² with no extra, the numbers are easy to scale:
| Compacted depth | yd³ per 100 ft² | US tons per 100 ft² | m³ per 9.29 m² | tonnes per 9.29 m² | ft² per ton |
|---|---|---|---|---|---|
| 2 in (51 mm) | 0.62 | 1.17 | 0.47 | 1.06 | 85 |
| 4 in (102 mm) | 1.23 | 2.35 | 0.94 | 2.13 | 43 |
| 6 in (152 mm) | 1.85 | 3.52 | 1.42 | 3.19 | 28 |
| 8 in (203 mm) | 2.47 | 4.69 | 1.89 | 4.26 | 21 |
| 12 in (305 mm) | 3.70 | 7.04 | 2.83 | 6.38 | 14 |
How thick should road base be?
For a driveway, plan on at least 6 in of compacted base, and more on soft ground or for heavy trucks. These are the published figures we could verify:
| Use | Base depth | Source |
|---|---|---|
| Gravel road surface | 6 in minimum; up to 10 in or more for heavy loads or poor soil | UW–Madison TIC, PASER Gravel Roads manual |
| Paver patio or walk | 4–6 in of crushed rock, thicker on soft clay or where driven on | Oregon State University Extension |
| Gravel surfacing layer | 1.5–2 in minimum to count as a gravel road surface | UW–Madison TIC, PASER Gravel Roads manual |
Two habits matter as much as the number. Place thick base in lifts and compact each one; Oregon State’s paver guide calls for three lifts with compaction between them. And build on a firm subgrade: base spreads a load, but it does not fix soft, wet soil underneath. If water ponds or the ground pumps under a truck tire, deal with drainage first.
A two-layer driveway is common: a coarser base, then a finer, tighter topping. For a 12 × 50 ft drive, 4 in of base and 4 in of topping are each 8.15 yd³ and 15.48 tons with 10% extra at 1.9 t/yd³. If the topping is a different product, run it through the calculator with that product’s density.
Road base vs crusher run vs #57 stone
They look similar in a pile but do different jobs. Road base and crusher run are dense-graded: stone plus fines that lock together when compacted. #57 is open-graded: clean stone of one size range, with no fines, that drains but does not lock.
| Material | What it is | Compacts hard? | Drains? | Typical use | Calculator density |
|---|---|---|---|---|---|
| Road base (aggregate base, flexible base) | Crushed stone or gravel with fines, often sold to a state DOT grade | Yes | Slowly | Driveway and road base, slab subbase | 1.9 t/yd³ compacted (Ohio DOT) |
| Crusher run (crush and run, DGA) | Unscreened crusher output: stone plus dust | Yes | Slowly | Base and top layer for drives, paths, pads | Ask your supplier |
| #57 stone | Clean crushed stone screened to one size range, no fines | No, it stays loose | Yes | Drainage, French drains, under slabs where specified | Ask your supplier |
Only the road base density is from a published source (Ohio DOT, compacted). Crusher run and #57 weights vary by quarry and by whether they are loose or compacted, so ask your supplier for a tested weight before converting yards to tons.
What a DOT grade adds. “Road base” on a quarry board often means a product made to a state spec. TxDOT Item 247, for example, sorts flexible base into types by source (Type A crushed stone from a single quarried source, Type B crushed or uncrushed gravel, Type C crushed gravel) and into grades by gradation and plasticity. Grade 1 passes a 1 3/4 in sieve and allows a plasticity index of no more than 10. California’s Class 2 aggregate base is the same idea under Caltrans rules. If your plans name a grade, buy that grade and ask for the supplier’s test data. If they do not, a local “road base” or crusher run is usually what driveway builders use.
Road base in metric
The method is the same in metres: length × width × depth gives m³. Multiply by about 2.25 t/m³ (the metric form of 1.9 US tons per yd³) for tonnes.
Worked example: 4 × 15 m drive, 150 mm compacted
- Volume: 4 × 15 × 0.15 = 9 m³, or 9.9 m³ with 10% extra (12.95 yd³)
- Weight: about 22.3 tonnes (24.6 US tons)
Switch the calculator to Metric to enter metres and centimetres; it shows m³ and tonnes alongside yd³ and tons. If your supplier quotes t/m³, type that into the density box in metric mode.
Common road base mistakes
- Mixing loose and compacted numbers. A loose density with a compacted depth and no allowance leaves you short.
- Adding compaction twice. With a compacted density like 1.9 t/yd³, 5–10% extra is enough.
- Going too thin. Under 6 in of base for a driveway is below what the UW–Madison gravel road manual calls the minimum.
- Building on mud. Base over soft, wet subgrade still ruts. Fix drainage and soft spots first.
- Using #57 where you need base. Clean stone drains but does not lock together; it is not a driving surface base by itself.
- Comparing quotes per yard and per ton. Convert with the supplier’s density before you compare.
All figures are ordering estimates. Your plans, your supplier’s tested density and local practice take priority over this calculator.
FAQ
Frequently asked questions
How many tons of road base are in a cubic yard?
About 1.9 tons once compacted. Ohio DOT's conversion table uses 3,800 lb per yd³ for compacted crushed stone. Loose in a truck it weighs less per yard. Ask your supplier for its tested weight.
How much road base do I need for a 12 × 50 ft driveway?
At 6 in compacted, 11.11 yd³, about 21.11 tons at 1.9 t/yd³. With 10% extra for edges and an uneven subgrade, order 12.22 yd³, about 23.22 tons (21.07 tonnes). At 4 in it drops to 8.15 yd³ and 15.48 tons with the same extra.
How much road base for 100 square feet?
At 4 in compacted, 1.23 yd³ and 2.35 tons. At 6 in, 1.85 yd³ and 3.52 tons. At 8 in, 2.47 yd³ and 4.69 tons. These use 1.9 t/yd³ and no extra; add 5–10% for edges and low spots.
How thick should road base be for a driveway?
Plan on 6 in or more of compacted base for anything a vehicle drives on. UW–Madison's PASER gravel roads manual says a minimum gravel thickness of 6 in is required, with 10 in or more for heavy loads or poor soil. Place it in lifts and compact each one.
How many square feet does a ton of road base cover?
About 43 ft² (4.0 m²) at 4 in compacted, 28 ft² (2.6 m²) at 6 in and 21 ft² at 8 in, using 1.9 tons per cubic yard. A thinner 2 in topping covers about 85 ft² per ton.
Is road base the same as crusher run?
Often, but not always. Both are dense-graded crushed stone with fines that compacts hard. Road base is a regional name for whatever base grade a quarry sells, often to a state DOT spec, while crusher run is the quarry's unscreened crusher output. #57 is different: clean stone with no fines.
How much road base do I need in metric?
Multiply length × width × depth in metres. A 4 × 15 m drive at 150 mm is 9 m³, or 9.9 m³ with 10% extra. At 1.9 t/yd³ (about 2.25 t/m³) that is about 22.3 tonnes (24.6 US tons).
Should I add extra road base for compaction?
Not if you use a compacted density like this calculator's 1.9 t/yd³: compaction is already counted in the weight. Add 5–10% for uneven subgrade, edges and spillage. If you use a loose density instead, add more for compaction and ask your supplier how much.
5 Sources
- Ohio DOT Construction and Material Specifications, Item 617, Table 617.06-1 conversion factors (compacted crushed stone 3,800 lb/yd³)
- TxDOT Item 247 Flexible Base, as adopted by the City of Abilene, TX (types, grades, measurement by yd³ or ton)
- UW–Madison Transportation Information Center, PASER Manual: Gravel Roads (minimum 6 in gravel)
- Oregon State University Extension, 10-Step Guide to Installing Pavers (4–6 in crushed rock base)
- NIST SP 811, Appendix B.9 conversion factors
Last reviewed October 10, 2026 by M Bilal. Found an error? Tell us.