How Much Topsoil Do You Need? A Complete Buying Guide

By Anthony Hudson · Updated July 30, 2026 · 6 min read

The short version: a cubic yard of topsoil covers about 100 square feet at 4 inches deep — but the right depth, and whether to buy bags or bulk, depends entirely on what you're building. Here's the full breakdown, plus the shortcut that skips the math.

The formula behind every topsoil order

Every topsoil quantity comes from the same three-step conversion: area in square feet, times depth in inches, divided by 12 (giving cubic feet), divided by 27 (giving cubic yards). A 10×10 raised garden area at 6 inches deep: 100 × 6 ÷ 12 ÷ 27 = 1.85 cubic yards. Our topsoil calculator runs this instantly from your own dimensions — enter length, width, and depth, and it hands you both the cubic yard total and a bag count.

How much depth your project actually needs

Depth is where people either overspend or come up short, and it depends entirely on what's going in the ground:

Raised beds are their own calculation since you're filling a box, not topping a surface: a standard 4×8-foot bed at 12 inches deep needs 32 cubic feet — almost exactly 1.2 cubic yards, or about 42 standard 40-lb bags. Enter those same dimensions into the topsoil calculator's advanced settings and it does this exact box math for you.

Bags or bulk delivery?

The crossover point is lower than most people expect, because topsoil is heavy — a cubic yard weighs 1,800 to 2,200 pounds, roughly double what mulch weighs. A standard 40-lb bag holds about 0.75 cubic feet, so one yard is 36 bags: hauling that from a garden center is a genuine workout, not a quick errand. Past about half a yard, bulk delivery usually wins on both price and your back — most suppliers charge a flat delivery fee, so one full load beats two carloads of bags every time.

Topsoil, garden soil, or compost?

These get used interchangeably but aren't the same product. Plain topsoil is the base fill — right for leveling, filling holes, and building up grade. Garden soil (or "garden mix") is topsoil blended with organic matter, better suited to anything you're planting directly into. Compost is pure organic material, usually mixed into either at 20–25% rather than used alone. For a raised bed or new planting area, a topsoil-compost blend grows noticeably better than straight topsoil for a modest price difference.

A buying tip that saves a second delivery

Topsoil settles after rain and foot traffic — often 10–15% within the first few weeks. If you're filling to a precise final grade (up to a patio edge, or level with a lawn), order slightly over the calculated amount and rake down, rather than ordering exactly to the number and finding a low spot later. For lawn leveling specifically, apply in thin half-inch layers over several weeks instead of one thick pour — grass grows through thin layers and gets smothered under thick ones.

Whatever the project, the topsoil calculator handles the volume math instantly — plug in your area and depth, and it returns cubic yards, a bag count, and a straight bags-vs-bulk recommendation based on your total.