The formula in words
Fill is sold and hauled by the cubic yard. A cubic yard is a box 3 feet long, 3 feet wide and 3 feet tall, which is 27 cubic feet. So the math is three steps. Measure the length and width of the area in feet. Work out the average depth you need to add, also in feet; if you have inches, divide by 12. Multiply the three numbers together for cubic feet, then divide by 27.
Odd shapes are easier in pieces. Split the area into rectangles, run each one, and add them up. Depth is rarely the same everywhere on a lot, so take readings at several spots and average them, or use the existing and proposed grades on your survey and site plan. For a quick feel: one cubic yard covers 27 square feet at 1 foot deep, 54 square feet at 6 inches and 108 square feet at 3 inches.
A worked example with round numbers
This is an example only, with numbers picked to make the math easy, not a quote for your lot. Say you need to raise an area 60 feet long and 50 feet wide by 1 foot.
60 times 50 is 3,000 square feet. Times 1 foot of depth is 3,000 cubic feet. Divided by 27, that is about 111 cubic yards of fill in place, compacted. Raise the same area 6 inches instead, and you use 0.5 for the depth: 1,500 cubic feet, or about 56 cubic yards.
Notice what that 111 means. It is the volume once the fill is down and rolled tight. It is not how many yards you order, and it is not how many truckloads show up. Truck capacity varies by truck, so always ask a supplier how many yards each load carries before you count trips.
Why you order more than the math says: compaction and shrink
Dirt in a truck bed is loose. It has air between the grains. When we spread it, wet it and roll it, that air gets squeezed out and the same dirt takes up less room. In Cape Coral the building inspector wants fill under a foundation compacted to at least 95 percent, tested in the bottom of the foundation, so this squeeze is not optional.
How much it shrinks depends on the material, its moisture and how it was dug, so there is no one honest percentage for every load. Sandy fill behaves differently from fill with shell or clay in it. We figure the allowance from the material we are using and the job in front of us, not from a rule of thumb. Some fill also goes into shaping side slopes, filling soft spots after stripping roots, and the tapered edge of a pad, which a flat rectangle on paper never shows.
How to use the fill calculator on this page
The calculator does the cubic-yard math for you. Enter the length and the width of the area in feet, then the depth you need to add. If the depth is given in inches, enter it in inches; if your plans give feet, convert it first (6 inches is 0.5 feet). The result is cubic yards of fill in place.
Treat that number the way the example above does: it is the compacted volume. Add the allowance your supplier or contractor gives you for the material you are buying. For a house pad, measure out past the footprint to include the shoulders, not just the slab outline. For a lot with low corners, run each section separately and add them. Use the answer as a planning number for budgets and bids, then confirm it against your site plan before you schedule trucks.
What sets the depth on a Cape Coral lot
The depth is not a guess; the plans set it. Cape Coral requires the top of the garage floor to be at least 1 foot above the crown of the road. The swale flow line elevations come from the city, and final grade needs at least 6 inches of fall in the first 10 feet away from the house. The approved site plan ties all of that together.
Flood zones add a limit. In a Special Flood Hazard Area, the city caps on-site fill for a single-family home at 12 inches unless the Building Official approves more, which is why many homes go on stem walls (see stem wall vs monolithic slab). In unincorporated Lee County, a site fill grading plan is required when final grade will sit more than 18 inches above the road crown or an adjacent developed lot. Fill may never be dumped into swales, drainage inlets or canals.
Fill dirt or topsoil: which goes where
People ask whether they need fill or topsoil, and the answer is usually both, in different places. Fill is the structural layer. Under a house pad or a driveway it has to compact and pass a density test, so it should be clean: no roots, muck, stumps, trash or chunks of concrete. Organic material rots, and the ground above it sinks.
Topsoil is for growing things. It belongs in a thin layer near the surface where sod or plants will root, never under a slab or a drive. Using topsoil to raise a lot wastes money and builds in settlement. If you are leveling low spots in an existing yard, a few inches of clean fill topped with a little topsoil before sod usually beats piling topsoil alone. Our sod installation crew grades that top layer before the grass goes down.
Delivery, spreading and getting it right the first time
Ordering the right number of yards is half of it. The other half is getting trucks onto the lot without trouble. Dump trucks need a firm path in and room to tip. On a Cape Coral lot that means staying off owl and tortoise protection zones, off the neighbor's vacant lot and out of the city swale, which has to keep flowing.
We deliver, spread and roll fill rather than leaving a pile in the yard, so the yards you buy end up where the plan wants them. If you would like a second set of eyes on your numbers, send the survey and site plan and we will check the math with you. See fill dirt delivery and hauling or house pads and lot fill, and reach us through the contact page for a free quote.
The short version
- Cubic yards = length x width x depth in feet, divided by 27.
- The math gives compacted volume in place; loose fill from the truck takes more room.
- Shrink depends on the material and its moisture, so ask for an allowance based on what you are buying.
- In Cape Coral flood zones, on-site fill for a single-family home is capped at 12 inches unless the Building Official approves more.
- Structural fill goes under pads and drives; topsoil only belongs in the thin top layer for grass and plants.
Quick answers
How much does a load of fill dirt cost?
Fill dirt runs $250 to $350 a load, depending on where the lot is and how far it is from the pit. Those are Chop's own ranges. Your exact price comes after he sees the lot, and the quote is free: call or text (239) 560-2996.
How deep will one cubic yard of fill spread over 100 square feet?
About 3 1/4 inches: 27 cubic feet spread over 100 square feet is 0.27 feet. That is compacted depth, so loose fill ends up a little thinner once it is rolled.
How many cubic yards of fill does a house pad take?
It depends on the pad size, the height above existing grade and the side slopes. Measure past the footprint to include the shoulders, run the formula, then add the shrink allowance for the material.
Should I use fill dirt or topsoil to raise my yard?
Clean fill to raise it, and only a thin layer of topsoil on top where sod will root. Topsoil under weight settles.
Why did my fill order come up short?
Usually because the order was based on compacted volume without an allowance for shrink, or the depth was measured in only one spot. Side slopes and soft spots also take extra.
See our fill dirt delivery or call (239) 560-2996.