About the Limestone Calculator
Crushed limestone is one of the most widely used building materials in North America. Quarries blast and crush limestone bedrock, then screen it into graded sizes that are known by numbers set by state transportation departments. Clean grades such as #57 drain freely and are used for drainage, driveway tops and under concrete. Grades with fines, such as #411, pack down into a firm, almost paved surface. Screenings, the dust left after crushing, make a smooth bed for pavers and flagstone.
This limestone calculator works out how much you need by grade. Enter the length, width and depth of the area and choose the grade, and it gives the volume in cubic yards, the weight in tons, the number of truckloads and, if you enter a price, the cost. Because the grades weigh different amounts per cubic yard, the same hole takes more tons of #411 than of #57.
How to Use the Limestone Calculator
Enter the length and width in feet and the depth in inches.
Choose the limestone grade.
Enter a waste and compaction allowance, the truck capacity and, optionally, the price per ton.
The Formulas
cubic feet = length × width × depth ÷ 12 × (1 + allowance)
cubic yards = cubic feet ÷ 27
tons = cubic yards × density for the grade
truckloads = ⌈tons ÷ truck capacity⌉Densities used, in US tons per loose cubic yard: #57 1.35, #411 1.5, screenings 1.4 and #3 1.3.
Step-by-Step Example
A 20 × 10 ft area, 4 inches deep, in #57 limestone with 5% extra, at $40 a ton.
volume 20 × 10 × 4 ÷ 12 = 66.67 ft³ × 1.05 = 70 ft³
yards 70 ÷ 27 = 2.59 yd³
tons 2.59 × 1.35 = 3.5 tons
cost 3.5 × $40 = $140
trucks one loadThe same area in #411 would weigh about 3.9 tons, and with a 15% compaction allowance about 4.3 tons.
Limestone Grades Explained
#3 is large stone of about 1½ to 2½ inches, used as the first layer of a gravel driveway or a construction entrance because it spreads loads and resists rutting. #57 is the all-purpose clean stone, about ¾ to 1 inch, used for drainage around foundations and French drains, under slabs and as a driveway top layer. #411 combines #4 stone with screenings, so the fines fill the gaps and lock the stone together when rolled; it makes a hard top for driveways and a firm base for sheds and patios. Screenings, also called limestone dust or manufactured sand, are used in thin layers to level paver and flagstone beds and for paths. Names vary by state, so describe the job to the quarry if you are unsure which grade you need.
Building a Limestone Driveway
A lasting gravel driveway is built in layers over firm subsoil. Strip the topsoil and roots, lay a woven geotextile if the ground is soft, then spread about 4 inches of #3 stone and compact it. Add 2 to 4 inches of #57 or #411 on top and crown the surface so water runs off to the sides. Each layer is calculated separately, so run the calculator once per layer with its own depth and grade. A finished driveway of about 6 to 8 inches holds up to cars and delivery trucks; thinner layers soon rut.
Compaction and Settling
Clean stone settles only slightly, so a 5% allowance covers uneven ground and spreading losses. Stone with fines compacts more: a loose layer of #411 can lose 10 to 20% of its thickness when rolled with a plate compactor. If you need a 4-inch compacted layer, order for about 4½ to 5 inches loose, or raise the allowance to 10 to 15%. The calculator lets you set this percentage to suit the job.
Ordering and Delivery
Quarries and landscape yards sell crushed stone by the ton, and their scales are the final word. Ask for their density for your grade, because moisture and the source rock make a difference. Trucks are loaded by weight up to a legal limit: small single-axle trucks carry about 5 to 8 tons, tandem dump trucks about 15 and tri-axles about 20. Ask the driver to spread the load by tailgating it out while driving slowly, which saves hours of wheelbarrow work. Make sure the truck has a firm route that will not damage lawns, septic systems or buried pipes.
Limestone Versus Other Stone
Limestone is softer than granite or trap rock, so it can break down faster under heavy traffic and its dust can turn sticky when wet. In return it is often the cheapest local stone and compacts very well. Some people avoid limestone near acid-loving plants because it can raise soil pH slightly as it weathers.
Understanding Your Result
The headline gives the tons of limestone of your chosen grade.
The volume line shows the cubic yards and cubic feet with your allowance.
The delivery line gives the number of truckloads.
The cost line multiplies the tons by your price per ton.
When Should You Use This Calculator?
Use it when ordering stone for a driveway, path, patio base or drainage trench.
Use it to compare the weight and cost of different grades for the same area.
Use it to plan how many truckloads to book.
Common Mistakes
Ordering by cubic yards when the quarry sells by tons. Convert with the grade's density.
Ignoring compaction. Stone with fines settles when rolled.
Using one grade for the whole driveway. Large base stone and a finer top work better.
Forgetting delivery access. A loaded truck is heavy and needs firm ground.