Construction calculators

Fill Dirt Calculator

Updated Sep 19, 2026 By Infinity Calculator
Rate Formulas
Unit System
Type or speak a description, then press the wand to fill the fields below.
Project Type
Presets set a typical depth, waste % and compaction % — every value stays editable.
Area Dimensions
Area Shape Mode
Calculation Mode
Slope/wedge halves the volume — use it when fill tapers from zero depth at one edge to full depth at the opposite edge.
Quick-Fill Dimension Presets
Shape Diagram
The diagram redraws from your current shape, dimensions and depth.
Fill Depth
Depth is normally entered in inches for residential and commercial fill work.
Fill Material & Compaction
Density drives the tonnage and truckload-by-weight figures.
Compaction Buffer
Compaction buffer: On
Fill dirt compresses and settles after placement — ordering 15% extra is the standard industry recommendation.
0%+15%30%
Buffer: 15%
Delivery & Optional Cost

Fill Dirt Results

Cubic Yards to Order (compaction + waste adjusted)
Estimated Weight to Order
Truckloads — Tandem Axle (14 cu yd)
Coverage Area
Base Volume (raw, no buffer)
Delivered (Loose) Volume
In-Place (Compacted) Volume
Cubic Feet (raw)
Estimated Weight (lbs)
Estimated Weight (tons)
Weight with 15% Compaction Buffer
Raw cubic feet: — Buffer: — Density: — Truck: — Mode: —
Active Density: —
Step-by-Step Solution
Volume Build-Up
Multi-Zone Totals (session only)
Zone Name Dimensions & Depth Cubic Yards Tons Truckloads Remove
No zones added yet — press Add Zone to accumulate multiple areas.
Grand Total 0.00 0.00 0

Introduction

Fill dirt is the soil used to raise low spots, build pads, fill holes, and level ground. Buying too little stalls your job. Buying too much wastes money. This fill dirt calculator tells you how much dirt to order before the first truck rolls in.

Enter your area as a rectangle, circle, triangle, acreage, or plain square footage. Add your fill depth in inches, feet, centimeters, or meters. Pick your soil type, and you get cubic yards, tons, pounds, and the number of truckloads you need.

Dirt settles once it is placed and packed down. That is why the calculator adds a compaction buffer, set at 15% by default. You can change that buffer, add a waste percent for spillage during hauling and spreading, and see the math laid out step by step.

You can also type your job in plain words, sketch the area on a scaled grid, add prices to get a cost estimate, and stack several zones into one grand total. Results copy and print in one click, so you can hand them straight to your supplier.

How to Use Our Fill Dirt Calculator

Enter the size of your area, how deep the fill will be, and the type of dirt. You get cubic yards to order, the weight in tons, how many truckloads you need, and the cost if you add a price.

Unit System: Pick Imperial for feet and tons, or Metric for meters and tonnes. All fields switch over for you.

Describe your project in plain language: Type or speak something like "300 by 80 feet, 8 inches of fill, clay soil," then press the wand button to fill the fields.

Project Type: Tap a job type like Building Pad, Parking Lot, or Utility Trench. This sets a normal depth, waste, and compaction. You can still change any number.

Area Shape Mode: Choose Rectangle, Circle, Triangle, Acreage, or Square Footage to match your site.

Length and Width: For a rectangle, type the two sides of your area and pick feet or meters.

Diameter: For a circle, type the distance straight across the middle.

Base and Height: For a triangle, type the bottom edge and the height straight up from it.

Acreage: Type the land size in acres or hectares if you already know it.

Area (direct entry): Type the square feet or square meters if you already have the area.

Calculation Mode: Choose Flat Fill for even depth. Choose Slope / Wedge Fill when the dirt tapers from zero at one edge to full depth at the other.

Quick-Fill Dimension Presets: Tap Small Yard, Backyard, or Foundation to load common sizes fast.

Draw Area on Map: Open this to sketch odd shapes. Set what one grid square equals, drag a box or tap corners, then press Use This Area to send it to the calculator.

Fill Depth: Type how deep the dirt will go and pick inches, feet, centimeters, or meters. Use the plus and minus buttons to nudge it.

Soil / Fill Type: Pick mixed, sandy, loam, silty, or clay fill. This sets the weight per cubic yard.

Compaction Buffer: Leave this on to order extra dirt for settling. Move the slider or tap a soil shortcut to set the percent. 15% is standard.

Waste / Overage %: Under Advanced Options, add extra for dirt lost during hauling and spreading.

Compaction %: Type an exact buffer percent here if you don't want to use the slider.

Truck Type: Choose your dump truck size so the calculator can count loads.

Price per Ton and Price per Cubic Yard: Add your supplier's price to see the total material cost. Leave blank to skip.

Calculate and Reset: Press Calculate to see results and the step-by-step math. Press Reset to start over.

Add Zone: Save the current result and add another area. The table adds up all zones for one grand total.

What Is Fill Dirt?

Fill dirt is plain subsoil dug from below the topsoil layer. It has little or no organic matter, so it does not rot, shrink, or sink much over time. That makes it the right material to raise low spots, build up a pad, fill a hole, or level a yard before you pour concrete or lay sod.

Fill Dirt vs. Topsoil

Topsoil is dark, rich, and full of roots and organic material. It is great for growing grass and plants, but it settles and breaks down, so it is a poor base for building. Fill dirt is the opposite. Use fill dirt for the bulk of the work, then add a few inches of topsoil on top if you plan to plant.

Common Uses for Fill Dirt

  • Building pads: a firm, level base under a house, shed, or slab
  • Parking lots and road base: raises grade before gravel or asphalt
  • Trench backfill: refills the ditch after pipe or cable goes in
  • Foundation backfill: packs soil back against basement or footing walls
  • Grading and drainage: slopes the ground so water runs away from buildings
  • Filling holes: old pools, stump holes, and washouts

How Fill Dirt Is Measured and Sold

Fill dirt is sold by the cubic yard or by the ton. One cubic yard equals 27 cubic feet, or a pile about 3 feet on every side. Weight depends on the soil type and how wet it is. Most fill dirt runs about 1.4 to 1.8 tons per cubic yard. Sandy fill is lighter. Clay is heavier and holds more water.

Why You Should Order Extra

Loose dirt takes up more room in the truck than it does after it is packed down. When you spread it and run a compactor or roller over it, the volume drops. That is called compaction or settling. Most jobs need about 10% to 25% extra. Sandy soil shrinks less, around 10%. Heavy clay shrinks more, around 20% to 25%. Add a little more, often 5% to 15%, for waste lost during hauling and spreading. Running short means paying for a second delivery, which costs far more than a few extra yards up front.

Truckloads and Delivery

Dirt is delivered by dump truck. A standard single-axle truck carries about 10 cubic yards. A tandem axle holds 12 to 14 yards, a tri-axle about 16 yards, and a semi end dump or belly dump can move 18 to 22 yards. Trucks are also limited by weight, so a load of wet clay may fill less space than a load of dry sand. Always round truckloads up, since you cannot buy half a load.

Tips for a Good Fill Job

  • Strip grass, roots, and soft mud before you place fill.
  • Place dirt in layers, or "lifts," about 6 to 8 inches thick, and compact each one.
  • Dirt that is slightly damp packs the best. Too dry will not bind; too wet turns to mush.
  • Slope the finished grade away from buildings so water drains off.
  • Check local rules. Many towns need a permit before you haul in large amounts of fill or change drainage.
  • Call 811 or your local utility locate service before you dig.

Formulas used

Coverage area (rectangle, circle, triangle)
A = L \times W \quad\text{or}\quad A = \pi\left(\frac{D}{2}\right)^2 \quad\text{or}\quad A = \tfrac{1}{2} B \times H
Fill volume (flat or slope/wedge)
V_{ft^3} = A \times d \times f,\quad f = \begin{cases} 1 & \text{flat fill} \\ 0.5 & \text{slope / wedge} \end{cases}
In-place volume in cubic yards
V_{yd^3} = \frac{V_{ft^3}}{27}
Delivered (loose) volume with compaction buffer
V_{loose} = V_{yd^3} \times \left(1 + \frac{C}{100}\right)
Volume to order including waste / overage
V_{order} = V_{loose} \times \left(1 + \frac{W_{\%}}{100}\right)
Material weight from density
W_{lb} = V_{yd^3} \times \left(\rho_{t/yd^3} \times 2000\right),\qquad W_{tons} = \frac{W_{lb}}{2000}
Number of truckloads
N = \left\lceil \frac{V_{order}}{C_{truck}} \right\rceil
Estimated material cost
C = P_{ton} \times M_{order} \;+\; P_{yd^3} \times V_{order}

Frequently asked questions

How many cubic yards of fill dirt do I need?

Multiply length by width by depth in feet, then divide by 27.

Example: a 30 ft by 20 ft area with 6 inches of fill is 30 × 20 × 0.5 = 300 cubic feet. Divide by 27 and you get about 11.1 cubic yards.

Then add 10% to 25% for settling and waste, so you would order around 13 yards.

How much does a cubic yard of fill dirt weigh?

Most fill dirt weighs about 2,000 to 2,700 pounds per cubic yard when dry.

  • Sandy fill: about 2,900 lb (1.45 tons)
  • Mixed or silty fill: about 3,100 lb (1.55 tons)
  • Sandy loam: about 3,240 lb (1.62 tons)
  • Clay-heavy fill: about 3,440 lb (1.72 tons)

Wet dirt can weigh 10% to 20% more, since water adds weight.

How many tons of fill dirt are in a cubic yard?

About 1.4 to 1.8 tons, depending on the soil and how wet it is.

Sandy fill runs near 1.45 tons per yard. Clay runs near 1.72 tons per yard. If you need to go the other way, one ton covers roughly 0.6 to 0.7 cubic yards.

How much fill dirt fits in a dump truck?

It depends on the truck size:

  • Single-axle dump: about 10 cubic yards
  • Tandem axle (10-wheeler): 12 to 14 cubic yards
  • Tri-axle: about 16 cubic yards
  • End dump semi: about 18 cubic yards
  • Belly dump: about 22 cubic yards

Trucks also have weight limits. Wet clay may hit the legal weight before the bed is full.

How much extra fill dirt should I order for compaction?

Order 10% to 25% extra. The right number depends on the soil:

  • Sandy or granular fill: about 10%
  • General residential fill: about 15%
  • Clay or structural fill: 20% to 25%

Loose dirt shrinks when you pack it down. A second delivery costs far more than a few extra yards.

How much area does one cubic yard of fill dirt cover?

One cubic yard is 27 cubic feet. Coverage depends on depth:

  • 2 inches deep: about 162 sq ft
  • 4 inches deep: about 81 sq ft
  • 6 inches deep: about 54 sq ft
  • 12 inches deep: 27 sq ft

To find it fast, divide 324 by the depth in inches to get square feet per yard.

How much fill dirt do I need to cover an acre?

One acre is 43,560 square feet. To cover it 1 inch deep takes about 134 cubic yards.

  • 1 inch: about 134 yd³
  • 6 inches: about 807 yd³
  • 12 inches: about 1,613 yd³

Add your compaction buffer on top of those numbers.

What is the difference between fill dirt and fill sand?

Fill dirt is subsoil, usually a mix of clay, silt, and sand. It packs tight and holds its shape, so it works for building pads and raising grade.

Fill sand drains fast and shifts more. It is used under pavers, around pipes, and in spots where water must move through. Sand also settles less, so you need less extra material.

Can you use fill dirt to grow grass?

Not by itself. Fill dirt has almost no organic matter, so grass and plants struggle in it.

Use fill dirt for the bulk of the job, then cap it with 4 to 6 inches of topsoil before you seed or lay sod.

How deep should fill dirt be under a concrete slab?

Most slabs sit on 4 to 12 inches of compacted fill, plus 4 to 6 inches of gravel base.

The exact depth depends on how much you need to raise the grade and on local soil. Place the fill in 6 to 8 inch lifts and compact each layer. Poor compaction under a slab leads to cracks.

What is a lift in fill dirt work?

A lift is one layer of dirt you spread and pack before adding the next.

Most crews use lifts of 6 to 8 inches for clay and silt, and up to 12 inches for sandy fill with heavy equipment. Dumping 2 feet at once means the bottom never gets packed, and the ground sinks later.

How long does fill dirt take to settle?

Compacted fill settles very little, and most of it happens in the first few weeks.

Dirt that is just dumped and not compacted can settle for 1 to 3 years and drop several inches. If you cannot compact it, mound it 10% to 15% higher than the finished grade and let rain pack it down.

Is fill dirt free?

Sometimes. Contractors digging basements or ponds often give dirt away just to avoid haul-off fees, but you usually pay for the trucking.

Bought fill dirt typically runs $8 to $25 per cubic yard, plus delivery. Screened or clean fill costs more than raw dirt. Free dirt can hide rocks, roots, and trash, so check it before you take it.

Do I need a permit to bring in fill dirt?

Often yes, especially for large amounts. Many towns require a grading or fill permit if you change drainage, move more than a set number of yards, or work near a wetland or flood zone.

Call your local building or zoning office first. Also call 811 before any digging so buried lines get marked.

What is the best fill dirt for a trench backfill?

Use clean granular fill or sand around pipes and cable, then native fill dirt above it.

Skip rocks, chunks of concrete, and organic matter near the pipe, since they can dent or crack it. Compact in 6 inch lifts so the trench line does not sink and leave a rut.

Why does clay fill need more extra material than sand?

Clay holds air pockets and water when it is loose. When you roll it, those spaces close and the volume drops a lot, often 20% to 25%.

Sand grains already sit close together, so they compress less, usually about 10%. That is why clay jobs need a bigger buffer.

How do I figure fill dirt for a sloped area?

If the fill tapers from zero at one edge to full depth at the other, the shape is a wedge. Find the flat-fill volume, then take half of it.

Example: 100 ft by 50 ft with fill going from 0 to 12 inches. Flat would be 185 cubic yards. The wedge is about 93 cubic yards.

If both edges have some depth, average the two depths instead.