Fill Dirt Calculator

What Is Fill Dirt Calculator?

The Fill Dirt Calculator is a focused estimating tool that converts site dimensions and target depth into compacted cubic yards, then scales that requirement for delivery, loads, and cost. Unlike generic volume tools, it accounts for shrink during compaction, waste/contingency, density for tons, and truck capacity, so the final plan reflects jobsite reality. Whether you’re building pads, grading yards, filling low spots, or backfilling trenches, the calculator exposes every intermediate number, enabling you to audit assumptions, compare quotes, and order confidently. Because inputs are modular—shape, depth unit, compaction, waste, density—you can quickly explore scenarios and avoid under-ordering or paying for unnecessary extra loads.

About the Fill Dirt Calculator

This calculator supports rectangular areas, circular areas, and linear trenches. You can enter depth in feet or inches, toggle a compaction loss fraction (e.g., 8–15%), and add a waste factor to cover irregularities, bulking, and grade tolerance. Density (tons per cubic yard) converts volume to weight for haul planning and scale tickets, while truck capacity (yd³ per load) returns rounded loads for dispatch. Outputs are organized for purchasing: compacted yards, delivered loose yards, adjusted yards after waste, tons, and loads—plus a clear path for pricing with per-yard or per-ton rates. With consistent formulas, the Fill Dirt Calculator standardizes planning across crews and projects.

How to Use this Fill Dirt Calculator

1) Choose shape: rectangle/square, circle, or trench. 2) Enter length and width (or diameter; for trench, length and trench width). 3) Enter target finished depth (in feet or inches). 4) Set compaction loss fraction k (typical 0.08–0.15) to scale compacted volume into delivered loose yards. 5) Add a waste factor w (e.g., 0.05–0.12). 6) Provide density (tons/yd³) and truck capacity (yd³/load). 7) Submit to see compacted yd³, delivered yd³, adjusted yd³, estimated tons, and truckloads. Revise inputs to compare deeper fill, changed density, or different truck sizes.

Examples Using the Fill Dirt Calculator

Example A (pad fill): 50 ft × 20 ft × 12 in. Compacted yd³ ≈ (50×20×12)/324 ≈ 37.04. With k=0.10 → delivered ≈ 37.04/0.90 ≈ 41.15 yd³. Waste w=0.05 → adjusted ≈ 43.21 yd³. Density 1.30 tons/yd³ → ≈ 56.2 tons. Truck 10 yd³ → loads = ⌈43.21/10⌉ = 5.

Example B (circular fill): Dia 30 ft, depth 8 in. Compacted yd³ ≈ [π×30²/4]×8/324 ≈ 17.45. k=0.12 → delivered ≈ 19.83 yd³. w=0.08 → adjusted ≈ 21.41 yd³. Density 1.25 → ≈ 26.8 tons. Truck 12 yd³ → loads = ⌈21.41/12⌉ = 2.

Example C (trench backfill): 120 ft × 3 ft × 18 in. Compacted yd³ ≈ (120×3×18)/324 = 20.00. k=0.15 → delivered ≈ 23.53 yd³. w=0.05 → adjusted ≈ 24.70 yd³. Density 1.35 → ≈ 33.3 tons. Truck 8 yd³ → loads = ⌈24.70/8⌉ = 4.

Core Formulas (rendered responsively)

Compacted volume when length/width are in feet and depth is in inches.

Compacted volume when all dimensions are in feet.

Compacted volume for circular areas using diameter in feet.

Use average depth when grade varies across the area.

Scale compacted volume by compaction loss fraction \(k\) (e.g., 0.10).

Apply waste/contingency factor \(w\) (e.g., 0.08).

Convert adjusted volume to weight using density \(\rho\).

Loads required based on truck capacity \(C\) in yd³ per load.

Key conversion between cubic feet and cubic yards.

FAQs

What is fill dirt used for?

It’s used to raise grades, build pads, fill low spots, backfill trenches, and prepare stable subbases for structures or landscaping.

How do I choose a compaction factor?

Typical planning values range 8–15%. Ask your supplier or engineer; moisture, lift thickness, and compaction equipment influence shrink.

Does the calculator include waste?

Yes. Add a waste fraction to cover irregular boundaries, measurement tolerance, bulking, and shaping losses during grading.

Can I enter depth in inches?

Yes. Use the mixed-unit formula; the calculator handles the 324 divisor automatically.

How many truckloads will I need?

Divide adjusted loose yards by truck capacity and round up. Example: 43 yd³ with 10 yd³ trucks → 5 loads.

How do I convert to tons?

Multiply adjusted yards by density in tons per yd³. Ask your supplier for a current density value for the specific material.

What density should I use for fill dirt?

Common planning range is 1.2–1.4 tons per yd³, depending on moisture and composition (clay, silt, sand, screened blends).

Can I handle irregular shapes?

Break the area into rectangles and circles, compute each, then sum yards. Add a slightly higher waste factor for complex edges.

What if the grade varies?

Use average depth: \((h_{\min}+h_{\max})/2\). For large variations, split the site into zones and compute separately.

Is this a substitute for a grading plan?

No. It’s an estimating aid. Final elevations, slopes, drainage, and compaction requirements must follow project specifications.

Why do supplier quotes differ from my estimate?

They may apply different compaction, density, or rounding rules, and include minimums or delivery zones. Compare assumptions line by line.