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Mulch Bed Calculator · Free calculator

12x12 Mulch Bed Calculator

Mulching a 12' × 12' bed (144 sq ft) 3" deep takes 1.40 cubic yards — 19 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 12x12.

Quick answer

3" deep (standard)
1.40 yd³
2 cu ft bags @ 3"
19
2 cu ft bags @ 2"
13
Bags cost @ 3"
$76
Bulk cost @ 3"
$60
Edging
48 LF

▍Mulch Calculator

Material
ft
in
ft
in
in
Waste Factor
$
L = 12' 0"W = 12' 0"D = 3"
Cubic Yards
1.40yd³
incl. 5% waste · Bulk delivery: order 1.50 yd³
Cubic Feet
37.80ft³
Area
144.0sq ft
Weight
0.42tons
Weight
840lbs
Mulch bags needed
  • 2 cu ft bag (2 ft³ yield)19

Mulch for a 12x12 bed by depth

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

DepthUseCubic yards2 cu ft bagsBags $Bulk $Weight
2"Refresh existing bed0.93 yd³13$52$40560 lbs
3"Standard (weed control)1.40 yd³19$76$60840 lbs
4"New bed / heavy weeds1.87 yd³26$104$801,120 lbs

Bed prep for 12x12

ItemQuantityNotes
Landscape fabric (3' × 50' rolls)2158 sq ft incl. 10% overlap
Bed edging (20' sections)348 LF perimeter
Fabric staples16~1 per 9 sq ft
Pickup loads (≈2.5 yd³)1bulk mulch @ 3"

How the math works

  1. Area: 12 ft × 12 ft = 144 sq ft
  2. Volume @ 3": 144 × (3 ÷ 12) = 36.00 cu ft
  3. Add 5%: 36.00 × 1.05 = 37.80 cu ft
  4. Cubic yards: 37.80 ÷ 27 = 1.40 yd³
  5. Bags: 37.80 ÷ 2 cu ft = 19 bags

Trade pro tips

  • 1.40 yd³ at 3" — bags are easier than bulk for this size.
  • 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 12x12 area?

At 3" deep, 19 bags of 2 cu ft mulch. At 2": 13 bags. At 4": 26 bags. All include 5% extra for 144 sq ft.

How many yards of mulch for 12x12?

2": 0.93 yd³; 3": 1.40 yd³; 4": 1.87 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 12x12 bed?

At 3": about $76 in bags or $60 in bulk before delivery. Bags are usually simpler at this size.

How much does the mulch for 12x12 weigh?

About 840 lbs at 3" (mulch runs 400–800 lbs per yd³ depending on moisture). That's 0.6 half-ton pickup loads of bulk mulch.