Fill Dirt Calculator for Holes, Trenches and Settled Ground
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The stake is still in the lawn where the excavator finished, the trench line has sunk two inches over the winter, and the ground is finally dry enough to walk without leaving prints. That is the week fill goes in. This dirt calculator turns what you can measure out there into yards.
Fill moves after mud season, not during it
Wet fill smears. It will not compact, it sticks to the wheelbarrow, and it leaves a cavity under the surface that shows up as a dip the following spring.
The window in New Hampshire runs from the end of mud season, once thawed ground has drained, through to the fall freeze. It closes later in the North Country and the higher valleys than it does in the Merrimack towns.
Two practical consequences. First, order for a dry stretch rather than the first mild week. Second, leave the pile high-sided so it sheds rain, and tarp it if a storm is coming, because a soaked pile takes days to become workable again.
Rain changes the weight of fill, not the volume. A yard is still a yard. It is only your wheelbarrow that notices.
Measuring a low spot that has three different depths
Nothing settles evenly, so a single depth reading is almost always wrong.
A dished lawn. Lay a straight board across the hollow from firm ground to firm ground. Measure down to the soil at the deep point, then at a couple of places near the edge. Average them. That average is the depth to enter.
A trench. Length, width and depth all as dug, straight into the boxes. Depth is in inches and the field stops at 24, so for anything deeper, halve the depth, run it, and double the answer.
A hole or old stump cavity. Round holes go in as a circle: diameter in feet, depth in inches.
A berm. Length by width by the average height you are building to. A berm is not a prism, so most people overshoot here; use the average height, not the peak.
The boxes, and the ten per cent
Pick the shape first: rectangle, circle, or multiple areas for up to five separate patches added into one total. That last one earns its keep on a lot with three or four sunken spots, since it gives a single delivery figure.
Length, width and diameter are in feet. Depth is in inches, anywhere from 0.25 to 24. Then choose the material, because that is what sets the weight.
The box adds 10% for compaction and spillage and is ticked by default. On fill it is worth leaving on. Loose fill consolidates, and some of every load stays in the grass.
Out come cubic yards, tons and cubic feet. Email my quote puts the result in writing.
Yards are what you order, tons are what arrives
Fill dirt is sold by the yard here. The ton figure is still useful, since it tells you what is landing on the drive.
- Dry fill dirt: about 2,400 lb per cubic yard, or 1.20 tons
- After a soaking: up to 3,000 lb per yard, or 1.50 tons
- Screened loam, for comparison: about 2,200 lb per yard, or 1.10 tons
Formula, if you want to check the screen: cubic yards = area sq ft x depth in, divided by 12, divided by 27. Tons = cubic yards x 1.20.
Backfilling a trench after the water line goes in
Hypothetical. Thirty feet of trench, 2 feet wide, backfilled 18 inches deep over the bedding.
- 30 x 2 = 60 sq ft
- 60 x 1.5 ft = 90 cu ft
- 90 / 27 = 3.33 cu yd
- 3.33 x 1.20 = 4.00 tons
- With the 10% box: 3.66 cu yd, 4.40 tons
Backfill in 6 to 8 inch lifts, compacting each one. A trench filled in one go will telegraph its whole length across the lawn by the second spring.
A saucer in the back lawn that has been sinking for years
Hypothetical. A saucer roughly 18 by 22 feet, averaging 5 inches down.
- 18 x 22 = 396 sq ft
- 396 x 5 = 1,980, divided by 12 = 165 cu ft
- 165 / 27 = 6.11 cu yd
- 6.11 x 1.20 = 7.33 tons
Fill to about half an inch proud of the surrounding grade and let it settle flush. If grass is going back over it, stop the fill 4 to 6 inches low and finish with screened loam. Fill dirt is subsoil with the organic matter screened out, which is exactly what you want under a grade and exactly what you do not want under seed.
Which of the three ground tools to open
They look alike and they are not.
| You are | Tool |
|---|---|
| Raising a grade, filling a hole, backfilling | this one, for fill dirt |
| Topdressing or building a lawn | the loam calculator |
| Filling raised beds and planting holes | the garden soil calculator |
Depth is what separates them in practice. Fill goes deep and stays put. Loam is the top 4 to 6 inches. Garden soil fills a box.
Keep wood and brush out of buried fill. Stumps and slash rot quietly and leave a sinkhole years later. And if the fill is going under a slab or footings, that is an engineered compaction specification and thinner lifts, not a lawn job.
One more thing worth separating out. Stone bedding in the bottom of a trench is not fill and is not measured here; size that on the gravel tool and order it as its own line.
With yardage in hand, open the product page, set a quantity and a date, and delivery is arranged at checkout by ZIP. How delivery works covers access and where a load of fill can safely be tipped on soft ground. Everything else on the job has an entry in the full set of calculators.
Common questions
Do I measure the hole as it is now, or after I have packed the bottom?
As it is now, loose and unpacked. The number you want is the empty space to be filled. Compaction is handled by the 10% box and by placing the fill in lifts, not by shaving the depth you enter.
An old stump left a round pit. How do I get its area?
Circle mode, and measure the diameter across the widest part. For arithmetic on paper, halve the diameter, square it, and multiply by 3.14. A 4 foot pit at 24 inches deep works out near 12.6 square feet, 25 cubic feet, and about 0.93 yards.
How do I sanity check the yardage before I commit to it?
Square feet times depth in inches, divided by 12, gives cubic feet. Divided by 27 gives yards. A useful landmark: one yard covers 81 square feet at 4 inches and 27 square feet at a foot deep.
Why does the same 6 inches cost more tons in fill than in loam?
Weight per yard. Fill runs near 2,400 lb dry, screened loam nearer 2,200, garden soil about 2,000. Same hole, different loads. Pick the material in the dropdown before you read the ton figure, or you will be comparing the wrong number.
Is 10% enough for a trench that has to carry a drive over it?
Not on its own. Under any surface that takes a wheel, compact in 6 to 8 inch lifts and expect to come back with a wheelbarrow or two once it has been through a freeze and thaw. The allowance covers handling losses, not the consolidation of deep fill.
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