Mulch Calculator
Working out how much mulch you need gets easier when the mulch calculator turns bed size and target depth into cubic yards of mulch, mulch bags, order buffer, weight, and optional bagged-vs-bulk mulch cost before you buy material.
Project Inputs
Order Summary
Suggested order
2.04 cu yd
Based on 1.85 cu yd measured volume for 200 sq ft at 3 in depth, plus a 10% order buffer. 1.6 cu m if your supplier quotes metric volume.
- Coverage area
- 200 sq ft
- Measured volume
- 1.85 cu yd
- Bag plan
- 28 bags
- Order weight
- 815 lb
18.58 sq m
50 cu ft
25 base at 2 cu ft each
370 kg
Formula Breakdown & Buying NotesShow details
Current calculation
How the current order was built
Area = length x width
20 ft x 10 ft = 200 sq ft
Volume (cu ft) = area (sq ft) x depth (ft)
200 sq ft x 0.25 ft = 50 cu ft
Cubic yards = cubic feet / 27
50 / 27 = 1.85 cu yd
Suggested order = measured volume x 1.10
50 cu ft x 1.10 = 55 cu ft (2.04 cu yd)
Bags = suggested cubic feet / bag size
55 / 2 = 28 bag(s)
Coverage per bag
8 sq ft
At 3 in depth with 2 cu ft bags
Cost formula
Add bag and/or bulk pricing to compare purchase cost.
Material profile
Selected mulch type and planning notes
Bark mulch
Organic mulch with an estimated density of 400 lb per cubic yard.
Best for
- Flower beds
- Tree rings
- General landscape refreshes
Watch for
- Can shift on steep slopes or in hard runoff
- Needs periodic top-ups as it settles and breaks down
Use Scenarios
Refresh layer
Top up an established bed without guessing
Use the mulch calculator to convert a thin refresh layer into cubic yards and bag count before you buy more bark or wood chips than the bed actually needs.
First order
Plan a new garden bed, tree ring, or border
If you are standing at a new bed asking how much mulch you need, measure the footprint and target depth once, then use the result to compare the measured volume, buffered order quantity, and handling weight before delivery day.
Buying choice
Compare bags with bulk delivery
Add optional bag and bulk pricing when you want the page to show whether bagged vs bulk mulch is the better fit for the project size, handling effort, and material cost.
Formula Explanation
Step 1
Measure the mulch footprint
Area = length x width
The calculator starts with the bed, border, or walkway footprint. Irregular areas should be broken into smaller rectangles before you total the mulch area.
Step 2
Convert the depth into feet
Depth (ft) = inches / 12 or centimeters x 0.0328084
Mulch depth is usually entered in inches or centimeters, but cubic-feet and cubic-yard math needs the depth expressed in feet first.
Step 3
Find the measured volume in cubic yards
Volume (cu yd) = area (sq ft) x depth (ft) / 27
Measured volume tells you the mathematical cubic yards of mulch needed before any overage, supplier rounding, or cleanup buffer is added to the order.
Step 4
Apply a buying buffer and bag math
Suggested order = measured volume x 1.10; bags = suggested cubic feet / bag size
The page adds a 10% buffer for settling, shape cleanup, and small losses, then converts the buffered volume into mulch bags if you plan to buy bagged mulch.
How to Read the Result
Primary output
Suggested order
This is the buffered amount to buy, not just the measured hole or bed volume. It helps you order cubic yards of mulch with a modest margin instead of running short near the end of the project.
Bag planning
Bag plan and per-bag coverage
Mulch bags are based on the selected bag size and the current depth. When the depth changes, the same bag covers more or less area, so the bag plan changes too.
Material read
Weight, type, and optional cost
Volume stays the same across mulch types, but weight, durability, and pricing can change a lot. That is why the page separates the yardage math from the material profile.
Quick reference: 1 cubic yard covers about
Coverage changes with depth, even though the yardage stays the same.
| Depth | Coverage | Metric equivalent |
|---|---|---|
| 1 in | 324 sq ft | 30.1 sq m |
| 2 in | 162 sq ft | 15.0 sq m |
| 3 in | 108 sq ft | 10.0 sq m |
| 4 in | 81 sq ft | 7.5 sq m |
Example Cases
Worked example
Case 1: 20 x 10 ft garden bed at 3 in
Inputs
- Area: 20 x 10 ft
- Depth: 3 in
- Mulch type: Bark mulch
- Bag size: 2 cu ft
Computed Results
- Area: 200 sq ft
- Measured volume: 1.85 cu yd
- Suggested order: 2.04 cu yd
- Bag plan: 28 bags
- Order weight: 815 lb
- Cost read: Bulk $85.56 vs bags $154.00; bulk saves $68.44
Interpretation
This is a common medium-size bed where the measured yardage is still manageable in bags, but the buffer pushes the shopping list high enough that bulk can become the cleaner buy.
Decision Hint
Use a case like this to compare whether the project is still a store-run job or whether a driveway delivery will save enough time and handling to be worth it.
Worked example
Case 2: 12 x 6 ft border refresh at 2 in
Inputs
- Area: 12 x 6 ft
- Depth: 2 in
- Mulch type: Wood chips
- Bag size: 3 cu ft
Computed Results
- Area: 72 sq ft
- Measured volume: 0.44 cu yd
- Suggested order: 0.49 cu yd
- Bag plan: 5 bags
- Order weight: 244 lb
- Cost read: Bulk $18.58 vs bags $35.00; bulk saves $16.42
Interpretation
A shallower refresh layer keeps the total volume low, so the job may still be easier to finish with a handful of larger bags even if the bulk cost on paper looks lower.
Decision Hint
For light top-ups, compare the price result with transport and cleanup effort instead of looking at material cost alone.
Worked example
Case 3: 8 x 1.2 m walkway at 7.5 cm
Inputs
- Area: 8 x 1.2 m
- Depth: 7.5 cm
- Mulch type: Rubber mulch
- Bag size: 3 cu ft
Computed Results
- Area: 9.6 sq m
- Measured volume: 0.94 cu yd
- Suggested order: 1.04 cu yd
- Bag plan: 10 bags
- Order weight: 376 kg
- Cost read: Bags $120.00 vs bulk $269.33; bags save $149.33
Interpretation
This metric example shows that a modest walkway can still need close to a full cubic yard once the depth is substantial, especially with a long-lasting but heavier material such as rubber mulch.
Decision Hint
When the material is expensive or unusually heavy, use the result to check both the budget and the handling plan before you commit to pickup or delivery.
Boundary Conditions
Sources & References
- University of Florida IFAS - Choosing and Installing MulchesUsed for coverage math, the common 2- to 4-inch planning range, and the reminder that mulch should not touch trunks or stems.
- University of Minnesota Extension - Mulching 101Used for homeowner-facing mulch guidance, including material selection, refresh behavior, and why mulch depth is a planning decision rather than just a decorative choice.
- Arbor Day Foundation - Arborist Advice: Mulching 101Used for tree-focused application guidance, especially the gap around trunks and the warning against volcano mulching.
- Mulch & Soil Council - Mulch Selection and Installation GuideUsed for practical selection and installation notes, including the difference between organic and inorganic mulch choices in common landscape situations.