Pennsylvania Gravel Calculator for Patios, Lanes and Creek Beds
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Shale that splits, clay that holds water, and a winter that freezes and thaws the same patch of yard again and again: Pennsylvania ground finds out fast when a stone layer came up thin. This gravel calculator turns your tape-measure numbers into cubic yards, tons and cubic feet, so the depth you planned is the depth that goes down. A worked job comes first, because seeing the arithmetic once makes the tool easy to trust.
A Paver Patio Base, Worked Line by Line
Example only. A 14 by 16 ft paver patio behind a house on clay ground, with 6 inches of 2A modified planned under the pavers. The 6 inches is this example's input, not a rule. Your paver maker's instructions and your own ground set the real figure.
| Step | Working | Result |
|---|---|---|
| Area | 14 x 16 | 224 sq ft |
| Depth in feet | 6 ÷ 12 | 0.5 ft |
| Volume | 224 x 0.5 | 112 cu ft |
| Cubic yards | 112 ÷ 27 | 4.15 yd³ |
| Tons at 1.50 t/yd³ | 4.15 x 1.5 | 6.2 tons |
| With the 5% box ticked | 4.15 x 1.05, then x 1.5 | 4.36 yd³, 6.5 tons |
2A modified is crushed stone with the fines left in, so it packs hard, and packed stone is heavy. That is why the example uses the road base line of the material list, at about 3,000 lb per cubic yard, and not the lighter gravel figure.
The problem this solves. A patio base that is two inches short looks fine the day the pavers go down. The cause shows up after a winter or two: a thin base over wet clay lets frost lift and drop the pavers unevenly. The fix is dull but reliable. Measure, let the math set the tonnage, and screed the base to full depth before the first paver is laid.
Two smaller jobs, same method
Dry creek bed (example). A 30 ft run, 3 ft wide, lined 4 inches deep with river rock. That's 90 sq ft x (4 ÷ 12) = 30 cu ft, then 30 ÷ 27 = 1.11 yd³. River rock sits at 1.35 t/yd³, so 1.11 x 1.35 = 1.5 tons.
Fire pit surround (example). A pea gravel circle 14 ft across, 3 inches deep, with a 4 ft pit in the middle. Pick the circle shape and enter 14 ft as the diameter. Area is 3.1416 x 7 x 7 = 153.9 sq ft, which is 38.5 cu ft, or 1.43 yd³, or 2.0 tons at 1.40. The pit itself is only 12.6 sq ft, about 0.16 tons, so taking it out drops the order to roughly 1.8 tons. On a job this small, most people keep the round-up.
How the Gravel Calculator Takes Your Numbers
- Pick a shape: rectangle, circle, or multiple areas. Multiple areas holds up to 5 pieces and adds them together.
- Enter length and width in feet, or the diameter in feet for a circle.
- Enter depth in inches. The box accepts anything from 0.25 to 24.
- Choose the material from the list.
- Tick "add 5% extra for compaction & spillage" if the stone will be packed or driven on.
- Press calculate. If you'd like the figure in writing, use Email my quote.
The math inside is the same as the table above: cubic yards = (length ft x width ft x depth in ÷ 12) ÷ 27, and tons = cubic yards x the density of the stone you picked.
What the Three Output Figures Tell You
- Cubic yards is the size of the pile. Handy for comparing against a truck bed or a job spec.
- Tons is how stone is weighed and sold, so it's the number you order from.
- Cubic feet is the small-job number, handy when you're filling a wheelbarrow of known capacity.
The weight side depends on the material you pick:
| Material in the list | lb per yd³ | Tons per yd³ |
|---|---|---|
| Driveway / walkway gravel | ≈ 2,800 | 1.40 |
| Pea gravel | ≈ 2,800 | 1.40 |
| Crushed stone (#57, 3/4") | ≈ 2,800 | 1.40 |
| Crusher run / road base | ≈ 3,000 | 1.50 |
| River rock | ≈ 2,700 | 1.35 |
Pennsylvania yards sell 2B stone and #57 stone as the same clean 3/4 inch size, so either one goes on the crushed stone line.
Ordering Tolerance on Hilly, Frost-Prone Ground
The 5% box covers stone that settles when it's packed and the bit that never leaves the tarp. Untick it for loose decorative cover that nobody compacts.
Hills change the picture. Water and loose stone both move downhill, so the low end of a sloped lane or pad often gets a thicker base. If you plan that, measure the low section as its own rectangle in multiple-areas mode and give it the deeper figure, rather than guessing at an average.
Frost here reaches about 36 inches in most of the state, from about 30 in parts of the southeast to 42 in the north and the mountains. No stone layer gets below that. What you control is drainage: a base that sheds water heaves far less than one sitting in wet clay. In limestone valleys, don't aim roof or drive runoff at one spot, since concentrated water can open sinkholes.
Picking Stone for Each Layer
- Base under drives, pads and patios: 2A modified, compacted in lifts.
- Surface on a drive: driveway gravel over the compacted base.
- Drainage, wet spots, wall backfill: 2B or #57, clean with no fines.
- Walkways and topping: 1B stone, the small clean chip, or walkway gravel.
- Foot traffic and play areas: pea gravel, rounded so it stays loose.
- Beds and creek beds: river rock.
Base stone shouldn't go down on frozen or muddy ground. Spring after the thaw has dried out, through late fall, is the working window.
Measure It, Then Order It
Run your own numbers above, open the product page for the stone the calculator sized, and choose your quantity and delivery date there. Delivery is arranged at checkout by ZIP code. If you can't tell 2B from 1B in what's already down, send a photo through the contact page and Pennsylvania Rock Supply will help you match it.
Common questions
About how many tons does a single-car gravel drive take?
Example: a 10 by 50 ft drive with 6 inches of 2A modified and 2 inches of driveway gravel on top. The base is 500 sq ft x 0.5 = 250 cu ft, or 9.26 yd³, which is about 13.9 tons at 1.50. The top is 500 x (2 ÷ 12) = 83.3 cu ft, or 3.09 yd³, which is about 4.3 tons at 1.40. Your own length and depth will move those numbers, so run them in the calculator.
What gravel should go under a patio seating area?
For a loose gravel sitting area, 2 to 3 inches of driveway gravel or 1B chip inside solid edging works. A 12 by 14 ft area at 3 inches is 42 cu ft, about 1.56 yd³ or 2.2 tons at 1.40. Under pavers, you're sizing a 2A modified base instead.
Weight and volume both show up in the results. Which one matters when I order?
Yards tell you how big the pile is. Tons are what the stone is weighed and sold by. The conversion depends on the material, which is why the tool asks you to pick one.
My lane runs up a hill. Do I measure level or along the ground?
Run the tape along the ground surface, since that's the area the stone has to cover. If the low end needs a thicker base, run it as its own calculation, since the depth box applies one figure to every area in a run.
Where should the truck drop a load this size?
Pick firm, level ground close to the work, clear of low wires and septic fields, with open access for the truck to back in and dump. A tarp under the pile saves a lot of raking on pavement.
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That tonnage ships free.
Driveway gravel, #57, crusher run: priced by the ton, delivered across Pennsylvania.
