Dirt Calculator is a free earthwork calculator for the four questions every dirt project asks: how many cubic yards does the shape need, what will it weigh, how much extra does compaction demand, and what should the whole order cost. We built it around one belief: a yardage figure is only trustworthy when you can see where it came from β the geometry, the density, the buffer, and the price it is multiplied against.
Every pile is a calculable numberPhoto: Unsplash6
Shapes: rect, slope, circle, triangle, ring, road
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Material densities built in
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Unit systems, converting in place
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Accounts, uploads, or saved inputs
The idea for this site came from a familiar frustration. Dirt advice is rarely written where you need it: it lives in a supplierβs rule of thumb that assumes one depth, or in a forum thread where βa yard covers 100 square feetβ is treated as physics, or in a generic online calculator that returns an answer with no visible method behind it β and never asks whether your fill is sandy or clay, loose or compacted. Chasing the number is easy; knowing whether to believe it is the hard part.
The strange thing is that the arithmetic is old, public, and short. Length times width times depth, divided by twenty-seven, is a formula a ten-year-old can run β and yet projects go short every weekend because the loose yard that arrived is not the compacted yard that was needed, or because the circle bed was measured as a square. What is scarce is not the math β it is the presentation. Calculators that show the formula, let you pick the material that matches your order, and refuse to pretend that loose volume and placed volume are the same number.
So we built the calculator we wanted to use. The flagship tool takes the shape, the dimensions, the material, and the compaction buffer as explicit inputs rather than hidden defaults, and answers with the order you should actually place β cubic yards and cubic meters, weight in tons, truckloads, retail bag counts for small jobs, and a cost total from the price you enter. Six shapes cover the projects that actually happen, and the βadd another areaβ button sums the front yard, the back yard, and the tree ring into one delivery.
And the site stays the way it started: free, without accounts, with every calculation running locally in your own browser. We have no interest in your project data β architecturally, we never receive it. The advertising that keeps the lights on sits clearly apart from the tools, and nothing about the answer is gated behind a subscription.
The method, visiblePhoto: UnsplashThe one-sentence version
We put the volume formula, the material density, and the compaction allowance on the same screen β so the number you order against is one you can defend.
A dirt project raises four practical questions β how much volume the shape holds, what that volume weighs, how much extra compaction demands, and what the order will cost delivered. The calculator takes each of those and answers it completely, and the answers chain: geometry produces the volume, density produces the weight, the buffer produces the order, and the price produces the budget.
From tape measure to orderPhoto: UnsplashThe flagship tool computes cubic yards, cubic feet, and cubic meters for the shapes dirt projects actually come in: flat rectangles, one-edge slopes (wedges), circles, corner triangles, hollow rings around trees and patios, and trapezoid road or trench sections. Add as many areas as the job has β front yard, back yard, and the ring around the oak tree all sum into one order quantity.
Volume is only half the order β the truck is rated in tons. The calculator multiplies your yardage by product-specific densities: about 1.55 tons per loose yard for mixed fill dirt, 1.3 for screened topsoil, 1.72 for clay-heavy fill, 1.0 for compost blends. Pick the actual material and the tonnage your supplier will quote falls out on its own.
Dirt shrinks when it is placed and compacted β typically 10% for sandy fill up to 25% for high-plasticity clay. A slider and presets fold the expected shrinkage into the order so the finished grade is not an inch short. For small jobs the result also converts to standard retail bag counts at 0.75, 1.0, 1.5, and 2.0 cubic feet per bag.
Enter a per-yard price and the tool totals the material cost, adds an optional delivery-fee estimate by ZIP code region, and shows how many truckloads the order fills β pickup bed, single-axle, tandem, or tri-axle. Everything lands in a copyable summary you can paste into a quote comparison or a text to your supplier.
The same arithmetic serves very different decisions β a delivery, a bid, a truck rental, a lesson. These are the people we had in mind while building it; if you recognize yourself in one of them, start with the tool that answers your question.
The most common visitor has a low spot to fill, a lawn to level, or a raised bed to build β and a supplier quote that says 'you need about eight yards.' Enter the actual dimensions, get the yardage with compaction already counted, and read any quote against a defensible number of your own.
Weekend warriors hauling their own material get the full picture: how many cubic yards the project needs, what that weighs in the truck bed (a half-ton pickup and three yards of wet fill are not friends), and whether bagged product from the garden center beats a bulk delivery for a job this size.
Bid preparation is arithmetic under time pressure. The calculator turns a sketch and a tape measure into per-area volumes, buffered order quantities, and tonnage in minutes β useful for double-checking a supplier's takeoff or explaining to a client why the settlement allowance is in the bid.
Backfill around a new pool, structural fill under a patio base, rough grade for a shed pad β these jobs live or die on settlement. The compaction presets and the per-area breakdown show exactly which zone carries the risk and how much extra material keeps the grade where it was drawn.
Raised beds, tree rings, and lawn topdressing run on different rules than structural fill: lighter compost blends, shallower depths, and bagged product that often wins on cost under five yards. The ring and circle shapes plus the bag-count output are built for exactly this scale of job.
Every formula is printed on the page, every density is in a visible table, and the worked example can be re-derived by hand. Change the compaction buffer and watch the order quantity move β earthwork stops being an abstraction and becomes a number you can defend.
Six commitments that shape every page on the site β the same commitments we would want from a tool we used on the job.
Every number the tool produces can be re-derived on paper: L Γ W Γ D Γ· 27 for a rectangle, ΟrΒ²D Γ· 27 for a circle, the trapezoid section formula for roads, and the buffer as a plain multiplier. A calculator that hides its method is a black box, and black boxes do not belong on a purchase order.
Density values follow published geotechnical and supplier reference data β loose delivered state, tons per cubic yard β separated by product: unscreened fill, screened fill, sandy fill, clay fill, topsoil, compost. The material you pick is the density the tool uses, not a generic average.
There is no account, no server round-trip, and no saved history on our side. Every calculation runs locally on each keystroke β which is also why results appear instantly and why the tools keep working once the page has loaded. Close the tab and the inputs are gone.
Loose volume and placed volume are different numbers, and the difference is where projects go wrong. Rather than hiding the shrinkage inside a mystery constant, the buffer is a visible control with published ranges per soil type β so the settlement allowance is part of the answer instead of a surprise in the second delivery.
No pro tier, no paywall in front of the real answer, no sign-up step between you and the yardage. The site is funded by clearly separated advertising; the calculator itself is not the product being sold, and no result is ever gated behind an upsell.
Smart length fields that accept 100, 100' 6", or 1200 inches alike, a unit toggle that converts every field together between imperial and metric, visual shape cards instead of jargon, and a worked example beside the method β the tool is written to be understood on first read, not decoded.
Every constant and table the calculator reads from traces to a published source. These are the sources, what each one governs, and where it shows up in the tools.
The grouping of fills β granular, sandy loam, silty, clay β follows the Unified Soil Classification System's distinctions, because compaction behavior and drainage follow the soil type, not the product name on the ticket.
Density values reflect published supplier and geotechnical reference ranges for loose delivered material β roughly 1.3β1.4 tons per yard for topsoil, 1.5β1.6 for mixed fill, up to 1.72 for clay-heavy fill β shown openly in the material table.
The 10β25% buffer range follows standard earthwork practice: granular fill shrinks least, high-plasticity clay most. The presets map to soil behavior so the allowance you choose matches the material you ordered.
The bag-count output uses the sizes actually on the shelf β 0.75, 1.0, 1.5, and 2.0 cubic feet β so the 'how many bags' answer matches what the garden center sells, not a theoretical package.
Truckload counts use real-world delivered capacities β about 2.5 yards in a half-ton pickup bed, 10 in a single-axle dump, 14 in a tandem, 16 in a tri-axle β so the logistics estimate matches what suppliers actually send.
Dirt Calculator is not affiliated with, endorsed by, or sponsored by any standards body, government agency, or material supplier. References are cited for identification and educational purposes β for work governed by a specification or a permit, consult the geotechnical report, the supplierβs certified density, and the local requirements that govern your job.
Three honest comparisons β against the calculators that hide their method, against the supplier habits every trade relies on, and against the folklore that fills the gap between them.
Plenty of online calculators return a number and nothing else. Here, the formula sits beside the inputs, the density constants are in a visible table, and the worked example can be followed line by line. When you can see the method, you can audit it β and an auditable answer is the only kind worth ordering ten tons against.
A good supplier carries years of rule-of-thumb β a yard covers 100 square feet at three inches, topsoil runs a ton and a third per yard β and for most jobs that habit is close. The calculator's job is different: show you which assumption moves the number. When a quote disagrees with a calculation, compare the depth and the compaction allowance first; the arithmetic is almost never the culprit.
Forum advice β 'order extra, dirt is cheap', 'a yard is a yard', 'bags are always a ripoff' β ignores that earthwork is a chain: the shape sets the volume, the material sets the weight, compaction shrinks the placed depth, and the truck rating sets the delivery. Numbers with their assumptions attached beat anecdotes every time.
The toolset grows from what users ask for at the estimate bench. Three directions are active right now β a written guide library, standalone material calculators, and deeper delivery coverage. Each one is chosen because it answers a question the current tool raises but cannot close.
Built from real job sitesPhoto: UnsplashLong-form guides on fill dirt vs. topsoil, compaction allowances by soil type, bags vs. bulk break-even points, and grading for drainage are on the workbench β each one written to end at a number you can enter somewhere.
Standalone topsoil, gravel, sand, mulch, and road-base calculators β each with product-specific densities and coverage charts β are the most requested additions from the estimate bench.
More ZIP-code regions, seasonal pricing notes, and clearer guidance on when a bulk delivery beats bagged product β growing from what users actually ask about.
Have a request? The fastest way to see a tool built is to describe the problem you were trying to solve β the contact page routes requests straight to the work queue.
The calculator lives on the homepage as one connected workflow β geometry feeds density, density feeds the order. These are the doors into it.
A note on responsibility
The calculator is a planning aid for estimating, comparing, and learning β not a substitute for a site-specific geotechnical design, a structural specification, or a qualified contractorβs judgment. For engineered fill, verify densities and compaction requirements where you build. See our full disclaimer for details.
Questions about the site, the data, or the method? Write to us β every message is read.