TryBuildCalcFill Dirt Calculator (Regrading / Filling Low Spots)
Size your fill dirt order instantly.
🕒 Last updated: September 19, 2026
Inputs
ℹ️Total lawn, bed, or plot area to be filled or topped with topsoil.
ℹ️Typical for Fill Dirt: 2-24 in.
ℹ️Unscreened subsoil/fill material — mainly mineral content with little organic matter — used for bulk grading, filling low spots, and building up grade rather than for planting directly. Depth varies widely by the grading work needed, so no single typical range applies; a topsoil layer is usually still added on top before planting.
Delivery
Shown as loose cubic yards / cubic metres, plus an approximate bulk/FIBC (≈1 m³) bag count for reference.
Cost
Topsoil Needed
6.389 cu yd
172.5 cu ft (4.885 m³ / 5 bulk bag(s) ≈1 m³ each)
Fill Area
300 sq ft
27.87 m² at 6" (15.2 cm) deep
Volume
Bare volume: 150 cu ft (5.556 cu yd / 4.248 m³)
Order volume (+15% settling/waste): 172.5 cu ft
6.389 cu yd / 4.885 m³ / 4,884.6 L
Bulk / Loose
Order: 6.389 cu yd (4.885 m³)
≈5 bulk/jumbo bag(s)
Assumes a ≈1 m³ (≈35 cu ft) bulk/FIBC bag, the common UK/AU size — a US bulk delivery is usually by the loose cubic yard instead.
Fill Dirt
Unscreened subsoil/fill material — mainly mineral content with little organic matter — used for bulk grading, filling low spots, and building up grade rather than for planting directly. Depth varies widely by the grading work needed, so no single typical range applies; a topsoil layer is usually still added on top before planting.
Typical depth range: 2-24 in (general practice guidance, not a fixed standard)
Assumptions Used
Order volume adds a 15% settling/waste allowance on top of the bare fill volume (area × depth), covering typical settling and compaction once topsoil is watered in and worked. Bag sizes are stored as a canonical liter volume so both common US cu-ft retail bags and common UK/AU litre bags can be selected from the same list; results are always shown in cu ft, cu yd, m³, and litres together. Bulk/loose figures assume a ≈1 m³ (≈35 cu ft) bulk/FIBC bag as an additional reference figure — many US suppliers instead sell bulk topsoil loose by the cubic yard, which is shown directly. This calculator estimates material quantity only — it does not verify existing grade, drainage, or soil testing/amendment needs.
Diagram simplified for clarity (not to scale) — fill area shown schematically, topsoil depth shown proportionally.
Looking for the verification checklist, reference tables, tips, or common mistakes?See the complete Topsoil Calculator.
Fill dirt volume for regrading
Fill dirt is unscreened subsoil used mainly for bulk grading and filling low spots — it's not intended for direct planting, so a proper topsoil layer is normally still added on top before seeding or landscaping.
This page defaults to a 300 sq ft area at 6 in deep with fill dirt — edit the inputs above to match your actual regrading project, which can vary widely in depth depending on how much the grade needs to change.
Topsoil Calculator Formula: How Is It Determined?
Fill area and depth combine into a bare volume, a settling/waste allowance is added, then the order volume converts to either a bag count or a bulk quantity.
Step 1 — Fill Area
By Dimensions: Area = Length x Width
By Total Area: Area = entered value (converted to sq ft if entered in m²)
Either enter a rectangular area's length and width, or enter its total area directly — useful for an irregular lawn, bed, or plot where length x width doesn't apply.
Step 2 — Bare & Order Volume
Bare Volume = Area x Depth
Order Volume = Bare Volume x (1 + 15% settling/waste)
The 15% allowance covers typical settling and compaction once topsoil is watered in and worked — a bit higher than a loose organic mulch's allowance, since topsoil compacts more.
Step 3a — Bagged
Bags = ceil(Order Volume / Bag Volume)
Bag volume is stored as a canonical liter figure internally, so both cu-ft-sized (US) and litre-sized (UK/AU) bags come from the same preset list, or enter a custom bag size in either unit.
Step 3b — Bulk / Loose
Order Volume shown directly in cu yd and m³
Bulk Bags (≈1 m³ each) = ceil(Order Volume in m³)
Bulk topsoil is most often bought loose by the cubic yard (common in the US) — the bulk/FIBC (~1 m³) bag count is shown as an additional reference figure, since that's a common bulk-bag size in the UK and Australia.
Worked Example
This example walks through your current inputs above, using the same steps as the Formula section.
Input Values Used
| Input | Value | Why it is used |
|---|---|---|
| Fill Area | 300 sq ft (27.87 m²) | Sets bare volume |
| Depth | 6 in (15.2 cm) — Fill Dirt | Sets bare volume and depth-advisory check |
| Delivery Method | Bulk / Loose | Sets bag count or bulk quantity |
Step 1 & 2 — Volume
| Calculation | Result |
|---|---|
| Bare Volume = 300 sq ft x (6/12) ft | 150 cu ft (5.556 cu yd / 4.248 m³) |
| Order Volume = Bare Volume x (1 + 15%) | 172.5 cu ft (6.389 cu yd / 4.885 m³) |
Step 3 — Bulk / Loose
| Calculation | Result |
|---|---|
| Bulk Bags = ceil(5 m³ / 1 m³) | ≈5 bulk bag(s) |
Figures above are rounded for display; the bag/bulk count is always calculated from full, unrounded values, so it can occasionally look off by one bag if you redo the division yourself using the rounded figures shown.
Therefore, a 300 sq ft area at 6" deep needs approximately 6.389 cu yd of fill dirt.
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Disclaimer: This calculator provides approximate results for planning and estimation purposes only. Actual requirements may vary based on site conditions, materials, workmanship, and local building regulations. Always consult a qualified engineer, architect, or construction professional before making final decisions.