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Mulch Bed Calculator · Free calculator

30x40 Mulch Bed Calculator

Mulching a 30' × 40' bed (1200 sq ft) 3" deep takes 11.67 cubic yards — 158 bags of 2 cu ft mulch with 5% extra. Here's 2", 3" and 4" depth, bag vs bulk cost and the fabric and edging for 30x40.

Quick answer

3" deep (standard)
11.67 yd³
2 cu ft bags @ 3"
158
2 cu ft bags @ 2"
105
Bags cost @ 3"
$632
Bulk cost @ 3"
$470
Edging
140 LF

▍Mulch Calculator

Material
ft
in
ft
in
in
Waste Factor
$
L = 40' 0"W = 30' 0"D = 3"
Cubic Yards
11.67yd³
incl. 5% waste · Bulk delivery: order 11.75 yd³
Cubic Feet
315.00ft³
Area
1,200.0sq ft
Weight
3.50tons
Weight
7,000lbs
Mulch bags needed
  • 2 cu ft bag (2 ft³ yield)158

Mulch for a 30x40 bed by depth

1200 sq ft, 5% extra. Bags ~$4.00 (2 cu ft), bulk ~$40/yd³.

DepthUseCubic yards2 cu ft bagsBags $Bulk $Weight
2"Refresh existing bed7.78 yd³105$420$3204,667 lbs
3"Standard (weed control)11.67 yd³158$632$4707,000 lbs
4"New bed / heavy weeds15.56 yd³210$840$6309,333 lbs

Bed prep for 30x40

ItemQuantityNotes
Landscape fabric (3' × 50' rolls)91,320 sq ft incl. 10% overlap
Bed edging (20' sections)7140 LF perimeter
Fabric staples134~1 per 9 sq ft
Pickup loads (≈2.5 yd³)5bulk mulch @ 3"

How the math works

  1. Area: 40 ft × 30 ft = 1200 sq ft
  2. Volume @ 3": 1200 × (3 ÷ 12) = 300.00 cu ft
  3. Add 5%: 300.00 × 1.05 = 315.00 cu ft
  4. Cubic yards: 315.00 ÷ 27 = 11.67 yd³
  5. Bags: 315.00 ÷ 2 cu ft = 158 bags

Trade pro tips

  • 11.67 yd³ at 3" — bulk delivery will be cheaper than bags.
  • Keep mulch 2"–3" away from trunks and siding — no "mulch volcanoes".
  • Refreshing an existing bed usually only needs 1"–2" on top.
  • One cubic yard of bulk mulch = 13.5 two-cu-ft bags.
  • A half-ton pickup carries 2–3 yd³ of mulch; a full-size bed with sides can take about 3.

Frequently asked questions

How many bags of mulch do I need for a 30x40 area?

At 3" deep, 158 bags of 2 cu ft mulch. At 2": 105 bags. At 4": 210 bags. All include 5% extra for 1200 sq ft.

How many yards of mulch for 30x40?

2": 7.78 yd³; 3": 11.67 yd³; 4": 15.56 yd³. Bulk mulch is sold by the cubic yard; 1 yd³ = 13.5 bags of 2 cu ft.

How much does it cost to mulch a 30x40 bed?

At 3": about $632 in bags or $470 in bulk before delivery. Bulk is usually cheaper at this size.

How much does the mulch for 30x40 weigh?

About 7,000 lbs at 3" (mulch runs 400–800 lbs per yd³ depending on moisture). That's 4.7 half-ton pickup loads of bulk mulch.