DIY Project Calculators
Tool Switcher: Fill Dirt
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Measure the gap. Confirm the order.

Fill Dirt Calculator

Calculate the space to fill across several rectangular areas, including a linear change in depth. Use your confirmed volume conversion to estimate loose fill dirt, optional weight and material cost.

  • Uniform depth or a simple wedge
  • No assumed compaction percentage
  • Cubic yards, cubic meters and supplier-based tons

Geometry before ordering

Fill Dirt Calculator

Measure the space to fill, then enter a confirmed conversion to loose material.

The starting 20 × 10 ft area and 12 in depth are arithmetic examples. Enter non-overlapping areas from your measurements. Conversion, density and price have no default values.

Area 1
Depth model
Convert geometric fill to a loose-volume order

Geometry only gives the size of the space to fill. It cannot establish the volume or weight to buy without a confirmed conversion.

Methodology

Separate the space to fill from the material to order

01

Measure the geometric fill

Uniform volume = length × width × depth. For a rectangular area with depth changing linearly along its length and constant across its width, volume = length × width × (start depth + end depth) ÷ 2. One end may have zero depth. This simple wedge model does not represent irregular terrain or a cut-and-fill survey.

US lengths use feet and depths use inches, so divide depth by 12. Metric lengths use meters and depths use centimeters, so divide depth by 100. Add non-overlapping areas before applying one conversion. Divide cubic feet by 27 for cubic yards.

02

Choose one confirmed conversion

A loose-volume allowance uses the geometric fill as its denominator: order = geometric volume × (1 + allowance ÷ 100). A loose-to-final volume reduction uses loose volume as its denominator: reduction = (loose volume − final fill volume) ÷ loose volume × 100, so order = geometric volume ÷ (1 − reduction ÷ 100).

For the same order, a 25% allowance equals a 20% loose-to-final reduction. They are alternative descriptions, not adjustments to stack. The allowance input supports 0–100% as a software limit, not a recommended range; reduction must be below 100%. No value is preselected. Without a confirmed conversion, the result is geometry only.

03

Convert loose volume to weight

Estimated weight = loose order volume × supplier density for that material and moisture condition. US density is lb/yd³; divide pounds by 2,000 for US short tons. Metric density is kg/m³; divide kilograms by 1,000 for metric tonnes. Density remains optional unless you enter a weight-based price. No universal fill dirt density is assumed.

04

Use a quote on the same basis

Material cost = loose volume × price per cubic yard or cubic meter, or estimated weight × price per US short ton or metric tonne. Switching units converts density and the quote to preserve the physical order and cost. The core retains precision; displayed values are shortened for readability. Orders are not rounded to whole yards, tons or truckloads. Delivery, tax and labor are excluded.

Worked example · illustrative inputs

A 20 × 10 ft area changing from 6 to 18 in deep

200 ft³geometric fill at 12 in mean depth

×

1.25example loose-volume allowance

→

250 ft³loose volume to order

The geometric fill is 200 ÷ 27 = about 7.407 yd³. A confirmed 25% loose-volume allowance gives 250 ft³, or about 9.259 yd³. A confirmed 20% loose-to-final reduction gives the same result: 200 ÷ 0.80 = 250 ft³. With an illustrative supplier density of 2,000 lb/yd³, the order weighs about 9.259 US short tons. At an illustrative $30 per yd³, material cost is about $277.78.

These percentages, density and price demonstrate the arithmetic; they are not recommended soil properties, a compaction specification or a current retail quote. The calculator initially shows geometry only and leaves those inputs blank.

Buying guidance

Check the order before checkout.

Frequently asked questions

A second look at the estimate.

How much fill dirt do I need?

First calculate the space to fill from the measured areas and depths. Then obtain a conversion to the supplied loose volume. Without that conversion, the calculator reports geometric fill only, not a purchase quantity.

Can I enter an area with a sloping fill depth?

Yes, when depth changes linearly from one end to the other along a rectangle and is constant across the width. Enter both end depths; the tool uses their average. Split other simple regions into non-overlapping areas. Irregular terrain requires a different measurement method.

Is 20% shrinkage the same as a 20% allowance?

No. A 20% loose-volume allowance multiplies geometric fill by 1.20. A 20% reduction measured relative to loose volume divides geometric fill by 0.80, giving a 25% increase. Always confirm the volume state and denominator before entering a percentage.

Can I use a bank shrinkage factor or a Proctor compaction percentage?

No. Bank-to-compacted factors start from undisturbed material volume and do not directly describe loose delivery volume. A Proctor compaction percentage is not this calculator's volume reduction. Use only a confirmed loose-to-final volume relationship; the calculator does not derive one from those values.

Can I calculate fill dirt tons and cost?

After entering a volume conversion, add the supplier's loose density to calculate weight. Material cost uses your volume or weight quote. A weight quote requires density. With no price, cost remains uncalculated; no density or price is assumed.

Should I use Fill Dirt or Topsoil?

Use Fill Dirt for geometric fill with uniform or linearly changing depth and an explicit conversion to loose supply. Topsoil combines landscaping areas at their own uniform depths and supports bag or bulk purchasing. Neither tool establishes that a material is suitable for a structural use.

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Sources and limitations

Geometric fill estimates for non-overlapping rectangles with uniform depth or depth changing linearly between two ends. A loose-volume order requires a user-confirmed conversion. No generic density, shrinkage, compaction target or engineering design is supplied. The loose-to-final reduction formula follows the explicit definition shown above. The FHWA source explains why material states and project-specific factors matter; its bank-to-compacted factors are not adopted as loose-volume inputs. This tool does not model excavation, cut-and-fill balancing, irregular surfaces, load-bearing capacity, drainage or installation methods.

Last reviewed: November 4, 2026