Mulch How Much Mulch Do I Need for 100 to 1,000 sq ft?
Short answer: 100 sq ft needs 0.62 cubic yards (9 bags of 2 cu ft) at 2 inches or 0.93 cubic yards (13 bags) at 3 inches. For any size, multiply square feet by depth in inches and divide by 324 to get cubic yards.
Key takeaways
- 100 sq ft: 0.62 yd³ at 2 inches, 0.93 yd³ at 3 inches.
- 500 sq ft: 3.09 yd³ (42 bags of 2 cu ft) at 2 inches, 4.63 yd³ (63 bags) at 3 inches.
- 1,000 sq ft: 6.17 yd³ at 2 inches, 9.26 yd³ at 3 inches.
- Each inch of depth over 100 sq ft adds 8.33 cu ft, or 0.31 cubic yards.
- Above about 2 yards (27 bags of 2 cu ft), compare bags with bulk delivery.
Find your bed size in the table below to see cubic yards and the number of 2 or 3 cu ft bags at the two most common depths. Bag counts are rounded up to whole bags.
| Area | 2 inches deep | 3 inches deep | ||||
|---|---|---|---|---|---|---|
| Yards | 2 cu ft bags | 3 cu ft bags | Yards | 2 cu ft bags | 3 cu ft bags | |
| 100 sq ft | 0.62 | 9 | 6 | 0.93 | 13 | 9 |
| 150 sq ft | 0.93 | 13 | 9 | 1.39 | 19 | 13 |
| 200 sq ft | 1.23 | 17 | 12 | 1.85 | 25 | 17 |
| 250 sq ft | 1.54 | 21 | 14 | 2.31 | 32 | 21 |
| 300 sq ft | 1.85 | 25 | 17 | 2.78 | 38 | 25 |
| 400 sq ft | 2.47 | 34 | 23 | 3.70 | 50 | 34 |
| 500 sq ft | 3.09 | 42 | 28 | 4.63 | 63 | 42 |
| 600 sq ft | 3.70 | 50 | 34 | 5.56 | 75 | 50 |
| 750 sq ft | 4.63 | 63 | 42 | 6.94 | 94 | 63 |
| 1,000 sq ft | 6.17 | 84 | 56 | 9.26 | 125 | 84 |
Formula: area (sq ft) × depth (in) ÷ 12 = cubic feet; ÷ 27 = cubic yards; cubic feet ÷ bag size = bags. Example: 200 sq ft at 3 in = 50 cu ft = 1.85 yd³ = 25 bags of 2 cu ft.
Common bed dimensions, already converted
Most people know a bed’s length and width, not its square footage. Here are typical dimensions with the math done. Bag counts are 2 cu ft bags, rounded up.
| Bed | Area | Yards at 2 in | Bags at 2 in | Yards at 3 in | Bags at 3 in |
|---|---|---|---|---|---|
| 3 × 10 ft border | 30 sq ft | 0.19 | 3 | 0.28 | 4 |
| 4 × 8 ft raised bed | 32 sq ft | 0.20 | 3 | 0.30 | 4 |
| Circle, 10 ft across | 78.54 sq ft | 0.48 | 7 | 0.73 | 10 |
| 4 × 20 ft foundation bed | 80 sq ft | 0.49 | 7 | 0.74 | 10 |
| 10 × 10 ft or 5 × 20 ft | 100 sq ft | 0.62 | 9 | 0.93 | 13 |
| 6 × 30 ft border | 180 sq ft | 1.11 | 15 | 1.67 | 23 |
| 10 × 20 ft bed | 200 sq ft | 1.23 | 17 | 1.85 | 25 |
| 8 × 40 ft island | 320 sq ft | 1.98 | 27 | 2.96 | 40 |
For round beds around trees, subtract the trunk area. The tree ring calculator handles that for you.
Sizes not in the table: scale it up
Mulch volume grows in a straight line with area and depth, so you can add rows together or multiply them:
- 1,500 sq ft = 1,000 + 500 sq ft. At 2 inches: 6.17 + 3.09 = 9.26 yd³. At 3 inches: 1,500 × 3 ÷ 324 = 13.89 yd³.
- 2,000 sq ft = 2 × 1,000 sq ft. That is 12.35 yd³ at 2 inches or 18.52 yd³ at 3 inches.
- 4 inches deep = double the 2-inch figure. 500 sq ft at 4 inches is 500 × 4 ÷ 324 = 6.17 yd³.
- Top-ups: use the depth you are adding, not the final depth. University of Illinois Extension advises checking existing mulch depth before adding more. 300 sq ft that needs 1 more inch takes only 300 × 1 ÷ 324 = 0.93 yd³.
To convert any of these yard figures to bags, see how many bags of mulch are in a yard.
How to measure an irregular bed
- Split it into simple shapes – rectangles, triangles and circles – and add up their areas.
- For curvy beds, measure the length along the middle and take the average of 3–4 widths; length × average width is usually within 10%.
- Subtract big obstacles such as patios or large shrubs you won't mulch under.
Bags or bulk?
Above roughly 2 yards (about 27 bags of 2 cu ft), bulk delivery often works out cheaper even with a delivery fee. Run your numbers in the bags vs bulk guide, or enter your exact dimensions and prices in the mulch calculator.
Frequently asked questions
How much mulch do I need for 100 square feet?
You need 16.67 cu ft (0.62 cubic yards, or 9 bags of 2 cu ft) at 2 inches, or 25 cu ft (0.93 cubic yards, or 13 bags) at 3 inches.
How many bags of mulch do I need for 200 square feet?
With 2 cu ft bags you need 17 bags at 2 inches or 25 bags at 3 inches. With 3 cu ft bags it is 12 or 17.
How many yards of mulch do I need for 500 square feet?
500 sq ft takes 3.09 cubic yards at 2 inches or 4.63 cubic yards at 3 inches.
How much mulch do I need for 1,000 square feet?
About 6.17 cubic yards at 2 inches or 9.26 cubic yards at 3 inches. That is 84 or 125 bags of 2 cu ft, so bulk delivery is usually more practical.
How much mulch for a 10 × 20 bed?
A 10 × 20 ft bed is 200 sq ft. It needs 1.23 cubic yards at 2 inches or 1.85 cubic yards (25 bags of 2 cu ft) at 3 inches.