Gravel Calculator for Ledge, Camp Roads and Shed Pads
Enter your project dimensions
Ledge decides how deep a lot of New Hampshire gravel goes, and no gravel calculator can see it from here. Measure, probe, then type.
The tool turns your feet and inches into cubic yards, tons and cubic feet. It does that part honestly. The rest is on you, and this page says which parts.
What the tool estimates, and what it leaves to you
It works out:
- Loose volume for a rectangle, a circle, or up to five separate areas added into one total.
- Weight in tons, from the density of the material you choose.
- An optional 5% extra for compaction and spillage.
It does not:
- Find ledge. If the bar hits rock at 4 inches where you planned 8, enter what you can actually fit.
- Know your frost. Frost reaches about 48 inches in the south of the state and 60 or more up north. Gravel sits well above that either way, so expect heaves every spring.
- Allow for mud season. Soft, thawing ground swallows stone that dry ground would hold up.
- Size armor stone. Culvert and bank work with big rock has its own rip rap calculator.
- Price anything. Prices live on the product pages.
Four units, one pile
People mix these up. Quick sort:
Square feet. Length times width. Flat area, no depth.
Cubic feet. Square feet times depth in feet. Three inches is 0.25 ft; six inches is 0.5 ft.
Cubic yards. Cubic feet divided by 27. The usual way to talk about a pile.
Tons. Cubic yards times the weight of one yard. A ton is 2,000 lb.
Stone doesn't all weigh the same. The calculator uses these figures:
| Tons in a yard | Pounds, roughly | Dropdown rows at that weight |
|---|---|---|
| 1.50 | 3,000 | Crusher run / road base |
| 1.40 | 2,800 | Driveway / walkway gravel; pea gravel (3/8"); crushed stone (#57, 3/4") |
| 1.35 | 2,700 | River rock (1-3") |
Put together: cubic yards = length (ft) x width (ft) x depth (in) ÷ 12 ÷ 27. Tons = that answer times the left-hand column.
Locally, the base row covers crushed gravel, the standard stuff under drives and pads. NHDOT specifies it as Item 304.3; that item number is how the material is described here, not a certification.
Running it
- Shape first. Rectangle for most things. Circle if it's round. Multiple areas if it's neither.
- Feet for the sides. Diameter, if round.
- Inches for depth. The box takes 0.25 up to 24.
- The stone, from the dropdown.
- The 5% box, if tires or a plate compactor will pack it.
- Calculate. Out come cubic yards, tons, cubic feet.
Want the figure in writing? Use Email my quote under the result.
One habit worth keeping: measure where the stone will stop, not where the grass happens to stop.
Three jobs, worked by hand
Examples only. Your ground will have its own opinions.
Ditch lining at a culvert outlet
A camp road culvert is scouring the ditch below it. Line 16 ft of ditch, 5 ft wide, 6 inches deep with 3/4 inch crushed stone.
- 16 x 5 = 80 sq ft
- 80 x 0.5 = 40 cu ft
- 40 ÷ 27 = 1.48 cu yd
- 1.48 x 1.40 = 2.07 tons
If spring runoff moves stone that size, it's a rip rap job instead.
Rock garden on a thin-soil knoll
Some spots have too little soil over the granite to bother planting. Cover a 12 x 7 ft bed with 3 inches of river rock.
- 12 x 7 = 84 sq ft
- 84 x 0.25 = 21 cu ft
- 21 ÷ 27 = 0.78 cu yd
- 0.78 x 1.35 = 1.05 tons
Loose cover. Untick the 5%.
Shed pad
The shed is 10 x 14. Make the pad a foot wider on every side, so 12 x 16, with 6 inches of crushed gravel.
- 12 x 16 = 192 sq ft
- 192 x 0.5 = 96 cu ft
- 96 ÷ 27 = 3.56 cu yd
- 96 ÷ 27 x 1.50 = 5.33 tons
- With the 5% box ticked: 3.73 cu yd, 5.60 tons
How much slack to order
Driven or packed stone: tick the 5%. Some people go to 10% on a new drive.
Loose cover in beds: no extra needed.
Rounding: round up, not down. Short is worse than a little left over.
Ledge: cuts the other way. Probe in several spots, average the real depth, and enter that. Where rock sits high, you may be building up rather than digging down. Then the depth you type is the finished height above the rock, and the pad's edges need grading to shed water.
Timing: base work runs from the end of mud season into late fall. Frozen ground won't compact, and wet ground in April eats stone.
Order it
Take the tons figure to the product page. Choose a quantity and a delivery date there, and delivery is arranged at checkout by ZIP code. Leave the truck firm ground and clear room to dump.
Not sure which stone matches what's already on your road? The contact page has the ways to call or text New Hampshire Rock Supply. Other materials have their own calculators.
Common questions
How close to right is the number it gives me?
As close as your measurements. The weights are rounded averages for dry material, so treat tons as a planning figure. Probe for ledge and average a few depth readings; that matters more than the decimals.
Same 4 inches, two different stones. Why do the tons come out different?
Weight per yard differs. Crushed gravel runs about 3,000 lb a yard, river rock about 2,700. Same volume, different load.
I'm filling a trench, not a flat patch. Will it work?
Yes. Trench length is the length, trench width is the width, trench depth goes in inches. The box stops at 24 inches, so for anything deeper, enter half the depth and double the answer.
What depth do I type for topping up an old drive, and what for a new one?
Topping up: about 2 inches of surface gravel. New: 3 to 4 inches of compacted base, then 2 to 3 inches on top. Run each layer as its own calculation.
I have my tons. Which product page do I order from?
The one matching the material row you picked. Crusher run / road base means crushed gravel or crusher run. Pea gravel means pea stone. Driveway / walkway gravel means driveway gravel or walkway gravel.
Related calculators
That tonnage ships free.
Driveway gravel, #57, crusher run: priced by the ton, delivered across New Hampshire.
