Compost Calculator

Topdressing a lawn uses a very thin layer, about a quarter to half an inch, raked in so the grass shows through. That is less than a cubic yard per 1,000 square feet. Beds take more: 2 to 3 inches worked into the top several inches of soil.

Building new raised beds? The raised bed soil calculator mixes compost with topsoil for you.

Measure the length and width in feet, multiply for square feet, then decide the depth in inches. For odd shapes, split the area into rectangles, circles, and triangles and add them up; the calculator lets you add as many areas as you need and subtract cut-outs like a tree ring or an air-conditioner pad.

No tape measure? Open the Draw on satellite map tab, find your address, and trace the outline. Or use Pace it off: count steps along each side. Measure depth in a few spots, because ground is rarely flat.

Want the area on its own first? The lawn size calculator measures any part of your yard and carries it into the other calculators.

A quarter inch over 1,000 sq ft takes about 0.77 cu yd. Half an inch takes about 1.5.

A cubic yard of compost weighs 800 to 1,200 lb (about 0.5 tons typical). Moisture is the big swing: the same pile weighs more after rain.

See every material side by side on the material weights chart.

It takes 27 bags of 1 cu ft to make one cubic yard, and each bag weighs about 40 lb. Bags cost more per yard but skip the delivery fee and the minimum order. Bulk is cheaper per yard once the delivery fee is spread over enough material.

With example prices of $7 a bag, $45 a yard in bulk, and $75 delivery, bulk starts winning at about 0.6 cubic yards. These are examples, not your local prices: type your own into the Order Ticket above and it recalculates the break-even.

Do not forget the labor. One cubic yard in bags means lifting 27 bags, about 1,000 lb in total, twice: into the cart and out of the car.

One cubic yard of compost weighs about 1,000 lb. A full-size half-ton pickup typically carries 1,500 to 2,300 lb, and a midsize pickup 1,100 to 1,700 lb. Your exact number is on the Tire and Loading Information sticker on the driver's door jamb.

That means weight runs out first. At the low end of a half-ton's payload, you can carry only about 1.5 cubic yards per trip, even though a 6.5 ft bed holds about 2.1 level full. A bed that looks half empty can already be over the limit.

The Haul Check in the calculator does this math for your truck and your load, and tells you how many trips it takes.

• Do not go over half an inch when topdressing an existing lawn. Thicker layers smother the grass. (Penn State Extension)
• For beds, work 2 to 3 inches into the top 6 to 8 inches of soil rather than leaving it on top. (Penn State Extension)

• Topdressing a lawn more than half an inch deep.
• Leaving compost in a thick layer on top of beds instead of mixing it in.
• Buying bags for a lawn job; bulk is far cheaper per yard.