About MulchVolume
MulchVolume is a free set of mulch quantity calculators and reference guides. It answers the practical questions that come up when you are about to buy mulch — how much you need, how many bags that is, what a yard of it tends to cost, and what the differences between the common materials actually are.
The site currently serves three audiences: the United States, the United Kingdom, and German-speaking readers. Each is treated as its own market with its own units, terminology and sources, rather than as a translation of the others.
How the calculators work
Every calculator here is built on geometry rather than on a lookup table.
You describe the area you are covering — a rectangle, a circle, or a total square footage you already know — and the depth of new mulch you plan to lay. The calculator multiplies area by depth to get a volume, then converts that volume into the units you actually buy in. One cubic yard is exactly 27 cubic feet, and that conversion is applied exactly, not approximated.
When you tell the calculator the size of the bag you are buying, it divides the required volume by that bag volume and rounds up to a whole bag, because you cannot buy part of a bag. When you give it a price, it multiplies through to a material subtotal.
Everything in that chain is arithmetic on the numbers you supply. The calculators run entirely in your browser: the dimensions, depths, bag sizes and prices you type into a calculator are not sent to MulchVolume.
Why the calculators ask you for numbers other sites guess
A lot of mulch calculators quietly fill in a bag size, a coverage figure, or a price for you. MulchVolume generally does not, and that is a deliberate editorial position rather than an omission.
Bag volumes differ between suppliers and between products from the same supplier. Coverage claims printed on a bag depend on the depth the manufacturer assumed. Delivered bulk prices depend on the region, the season, the quantity and the delivery terms. A single hard-coded default would make the tool feel more convenient while making the answer less true for most people using it.
So where a value genuinely varies, the site asks you to read it off the bag, the product page or the quote in front of you. The number you get back is then about your actual purchase rather than an industry average.
Where the figures come from
Statements about materials — how a mulch behaves, what depth a body recommends, what a surfacing material is used for — are attributed on the page to the organisation that published them.
For the United States that generally means university Cooperative Extension services, the USDA Forest Service, and, for playground surfacing, the U.S. Consumer Product Safety Commission. For the United Kingdom it means the Royal Horticultural Society and comparable institutional material. For the German pages it means the Landesbetrieb Landwirtschaft Hessen and the Bayerische Landesanstalt für Weinbau und Gartenbau.
The intention is not to accumulate citations. It is that when the site tells you a figure, you can see whose figure it is, and follow the link to read it in its original context.
Where a number cannot be sourced responsibly, MulchVolume leaves it out. If a whole topic cannot be covered without inventing a constant, the page stays unpublished until it can be. That has happened, and those pages are simply not on the site.
Three markets, not one translated site
The UK pages use litres, bark terminology and UK institutional sources. The German pages use the vocabulary German suppliers and state horticultural bodies actually use, and cite German sources. The US pages use cubic yards, cubic feet and US sources.
Where two markets genuinely disagree — and they sometimes do, particularly on recommended depth — the site reports both positions and attributes each, rather than averaging them into a single number that no source actually published.
What these calculators do not do
They do not know your supplier's real bag sizes, current prices, delivery minimums or availability. A cost figure produced here is an estimate built from numbers you entered; it is not a quote, and MulchVolume is not the supplier.
They are not a substitute for professional landscaping or arboricultural advice on a specific site.
The playground surfacing material on this site describes what the published standards say about loose-fill surfacing. It does not certify an installation and does not determine a safe depth for a particular piece of equipment. That requires the applicable standard and an assessment of the actual site.
Contact
Questions, corrections and problem reports are welcome. You can reach MulchVolume through the contact page.