A free mulch calculator for beds and tree rings, in cubic yards or bags.
See how much mulch your beds need in cubic yards or bags, at the depth Penn State Extension suggests.
Your numbers
Add an area for each bed. A circle around a tree takes the distance across it.
Your result
Fill in the fields above to see your result.
Embed this tool on your site
Paste the code into any page: WordPress, Webflow, Squarespace, Ghost or plain HTML. It's free with the credit under it, which links back to navid.me.
This free mulch calculator works out how much mulch your beds and tree rings need, in cubic yards for a delivery or in bags.
It takes rectangles, circles and triangles, so a bed and the ring around a tree go in together.
I built it because mulch comes in bags and in bulk by the yard, and the count decides which you buy.
Here's how deep to spread it, a worked example, and the mistakes to avoid.
TL;DRKey takeaways
What is a mulch calculator?
A mulch calculator turns the size of your beds and the depth you want into the mulch to buy.
It gives cubic yards for a bulk delivery, and bags of 1.5, 2 or 3 cubic feet.
How deep to spread mulch
Penn State Extension's guide to mulching trees gives the depths, and warns when the layer's too deep.
| Mulch | Depth |
|---|---|
| Organic mulch | 2 to 4 inches |
| Finely textured or double-shredded | 1 to 2 inches |
| Poorly drained soil | Less |
It also says to keep mulch off the trunk: 3 to 5 inches away from young trees, and 8 to 10 inches from mature ones.
A worked example
Here's the example the calculator loads: a 20 by 4 foot bed and a tree ring 8 feet across, 3 inches deep.
80 + 50.3 = 130.3 square feet. × 3 ÷ 12 = 32.6 cubic feet, or 1.21 cubic yards. That's 17 bags of 2 cubic feet.
Mistakes to avoid
These are the slips that come up most.
- Piling mulch against the trunk
- Spreading more than 4 inches
- Leaving the depth in inches when dividing by 27
Who is the mulch calculator for?
It's for gardeners and anyone tidying their beds, and these tools help around it.
- Cubic yard calculator – for soil or compost
- Gravel calculator – for paths between beds
- Square footage calculator – for any area
Spread it 2 to 4 inches deep, and your trees will thank you.
Plan your money with your AI
Take your numbers further in
Mulch Calculator FAQs
Questions about the mulch calculator? Here's what to know.
A mulch calculator works out how much mulch your beds need, in cubic yards or bags.
Multiply square feet by the depth in inches, divide by 12, then divide by 27 for cubic yards.
2 to 4 inches, by Penn State Extension, and 1 to 2 for finely textured mulch.
13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet.
About 108 square feet at 3 inches deep.
3 to 5 inches from young trees and 8 to 10 inches from mature ones, by Penn State Extension.
Yes, switch to meters and type the depth in centimeters.
Yes, it's free with no sign-up.
It runs in your browser, and your numbers stay on your device.
I did.
I'm Navid Moazzez, and I made the mulch calculator as one of my free tools on navid.me.
More about me.
Navid Moazzez
AI business strategist & AI OS builder
Navid Moazzez helps creators and founders master AI and build their own AI Operating System (AI OS) to automate their business and life.
Navid.me is reader-supported. When you buy through links on this site, I may earn an affiliate commission. Learn more.
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