Cubic to Feet Calculator
Soil Volume Calculator - ft³ · yd³ · Bags · Raised Beds

Soil Calculator - Cubic Feet

How Many Cubic Feet of Soil Do I Need? Raised Beds, Garden Beds, Topsoil & Fill Dirt

Use our free soil calculator in cubic feet to instantly find out how much soil, topsoil, or fill dirt you need for any project. Supports rectangular beds, circular beds, raised bed presets, and custom topdress depth inputs. Get results in cubic feet and cubic yards, plus bag count for 1 cu ft, 1.5 cu ft, 2 cu ft, and 40 lb bags, with a cost estimate for both bags and bulk delivery. Whether you're filling a raised garden bed, topdressing a lawn, or checking topsoil calculator cubic feet needs for a new landscape, this soil calculator cubic feet page gives you the full formula with practical buying guidance.

🌱 Raised Garden Beds🌿 Garden Bed Topdressing🏡 Lawn Topdressing🏗️ Fill Dirt & Grading

Bulk Conversion

1 yd³ = 27 ft³

Classic 4x8 Bed

32 ft³ at 12"

Best Depth

12" for most beds

Coverage

1 yd³ covers 27 ft² @ 12"

Soil cubic feet calculator
LWDepth

Rectangular Soil Inputs

Use standard mode for rectangular garden beds, circular borders, and any in-ground area where you are adding a measured soil layer.

Switch between rectangular and circular while keeping multi-area totals in one running calculation.

ft
ft
in

Use 3" for refresh layers and 12" for full raised-bed style fill.

%

Use 10% for settling, grading, and uneven fill.

Best for in-ground beds, topdressing, and general garden fill.

Multiple Areas

Add up to 5 areas

Use this for multiple garden beds or separate circular planters with their own soil type.

100 ft³

110 ft³ with overage

Total before overage100 ft³

How Deep Should Your Soil Be?

Recommended soil depth by plant type and application, with cubic feet impact.

🌿

Lawn Topdressing

Depth: 1/4" - 1/2"

Best for

  • • Lawn topdressing and leveling
  • • Overseeding prep
  • • Filling low lawn spots
  • • Improving soil under turf

Volume impact

  • • 1,000 ft² at 1/4" = 20.8 ft³ (0.77 yd³)
  • • 1,000 ft² at 1/2" = 41.7 ft³ (1.54 yd³)

Best soil: Screened topsoil or compost only.

Never exceed 1/2" in a single pass. Deeper layers can smother grass.

🌸

Flower Beds & Borders

Depth: 6-8 inches

Best for

  • • Annual flower beds
  • • Perennial borders
  • • Shallow ornamentals
  • • Decorative in-ground beds

Volume impact

  • • 100 ft² at 6" = 60.5 ft³ with overage
  • • 100 ft² at 8" = 80.7 ft³ with overage

Best soil: Topsoil plus compost mix, about 70/30.

Loosen the existing soil 2" to 3" before adding fresh soil for better root penetration.

🥬
GOOD FOR MOST VEG

Shallow Vegetables

Depth: 8-12 inches

Best for

  • • Lettuce, spinach, and greens
  • • Herbs
  • • Small radishes and beets
  • • Strawberries

Volume impact

  • • 100 ft² at 8" = 80.7 ft³ with overage
  • • 100 ft² at 12" = 121.0 ft³ with overage

Best soil: Raised bed mix with topsoil, compost, and perlite.

A 4x8 bed at 12" deep takes 32 ft³ before overage, or about 1.19 yd³.

🍅
RECOMMENDED

Deep-Rooted Vegetables

Depth: 12-18 inches

Best for

  • • Tomatoes and peppers
  • • Cucumbers and squash
  • • Beans and peas
  • • Most full vegetable gardens

Volume impact

  • • 100 ft² at 12" = 121.0 ft³ with overage
  • • 100 ft² at 18" = 181.5 ft³ with overage

Best soil: Premium raised bed mix with compost and aeration.

A 4x8 bed takes 32 ft³ at 12" and 48 ft³ at 18" before overage.

🥕

Root Vegetables

Depth: 18-24 inches

Best for

  • • Carrots and parsnips
  • • Potatoes
  • • Daikon radish
  • • Long-root crops

Volume impact

  • • 100 ft² at 18" = 181.5 ft³ with overage
  • • 100 ft² at 24" = 242.0 ft³ with overage

Best soil: Loose, rock-free mix with compost and coarse sand or perlite.

Compacted soil creates forked or stunted roots, so texture matters as much as depth.

🌳

Trees, Shrubs & Fill Dirt

Depth: 12-36 inches

Best for

  • • Backfilling low areas
  • • Tree and shrub planting zones
  • • Grading and leveling
  • • Foundation transitions

Volume impact

  • • 100 ft² at 12" = 121.0 ft³ with overage
  • • 100 ft² at 24" = 242.0 ft³ with overage
  • • 100 ft² at 36" = 363.0 ft³ with overage

Best soil: Fill dirt for structure, then topsoil on the plant root zone.

Use fill dirt for the base and cap it with topsoil if roots need to grow in the finished grade.

Topsoil vs. Fill Dirt vs. Potting Mix

Topsoil: the plant-growing layer for gardens, lawn topdressing, and landscape beds.

Fill dirt: structural fill for leveling, grading, and backfill, not for roots.

Potting mix: lightweight container media, too expensive and too airy for large in-ground jobs.

Compost: the best amendment for soil health, usually mixed in rather than used alone.

Key Soil Facts

  • • 1 yd³ = 27 ft³
  • • 40 lb bag ≈ 0.75 ft³ topsoil
  • • 1.5 cu ft bag = common garden-soil size
  • • 2 cu ft bag = common bulkier retail size
  • • 4x8 ft bed at 12" needs 32 ft³ before overage
  • • Add 10% overage when ordering

Raised Bed Quick Reference

  • • 4x4 ft at 6" = 8.0 ft³
  • • 4x4 ft at 12" = 16.0 ft³
  • • 4x8 ft at 6" = 16.0 ft³
  • • 4x8 ft at 12" = 32.0 ft³
  • • 4x8 ft at 18" = 48.0 ft³
  • • Formula: ft³ = L x W x H(in) ÷ 12

1 Cubic Yard Coverage

  • • At 1" = 324 ft²
  • • At 2" = 162 ft²
  • • At 3" = 108 ft²
  • • At 6" = 54 ft²
  • • At 12" = 27 ft²
  • • At 24" = 13.5 ft²

Raised Bed Soil Calculator - Quick Reference

Pre-calculated cubic feet for common raised bed sizes and depths.

Bed SizeDepth 6"Depth 8"Depth 10"Depth 12"Depth 18"Depth 24"
4x2 ft4.0 ft³5.3 ft³6.7 ft³8.0 ft³12.0 ft³16.0 ft³
4x4 ft8.0 ft³10.7 ft³13.3 ft³16.0 ft³24.0 ft³32.0 ft³
4x6 ft12.0 ft³16.0 ft³20.0 ft³24.0 ft³36.0 ft³48.0 ft³
4x8 ft16.0 ft³21.3 ft³26.7 ft³32.0 ft³48.0 ft³64.0 ft³
4x10 ft20.0 ft³26.7 ft³33.3 ft³40.0 ft³60.0 ft³80.0 ft³
4x12 ft24.0 ft³32.0 ft³40.0 ft³48.0 ft³72.0 ft³96.0 ft³
4x16 ft32.0 ft³42.7 ft³53.3 ft³64.0 ft³96.0 ft³128.0 ft³
4x20 ft40.0 ft³53.3 ft³66.7 ft³80.0 ft³120.0 ft³160.0 ft³
Convert ft³ to bags or yd³: divide by 27 for cubic yards, divide by 2 for 2 cu ft bags, or divide by 1.5 for 1.5 cu ft bags and round up. For example, a 4x8 ft bed at 12" depth needs 32 ft³ base volume, which is 1.19 yd³ or 16 x 2 cu ft bags before overage.

Soil Volume Formulas - All Shapes & Applications

Use these formulas to verify cubic feet, cubic yards, bag counts, and topdress coverage.

Soil Volume Formulas (cubic feet)

RECTANGULAR BED:
  ft³ = Length(ft) x Width(ft) x Depth(in) ÷ 12

CIRCULAR BED:
  ft³ = pi x (Diameter(ft) ÷ 2)² x Depth(in) ÷ 12

MULTIPLE RAISED BEDS:
  ft³ = Length x Width x Depth(in) ÷ 12 x Quantity

TOPDRESSING:
  ft³ = Area(ft²) x Depth(in) ÷ 12

UNIT CONVERSIONS:
  yd³ = ft³ ÷ 27
  2 cu ft bags = ft³ ÷ 2
  1.5 cu ft bags = ft³ ÷ 1.5
  40 lb bags = ft³ ÷ 0.75

OVERAGE:
  Order = calculated ft³ x 1.10

COVERAGE:
  ft² = ft³ x 12 ÷ Depth(in)

Raised Bed vs. Garden Bed

In-ground garden beds use a surface layer added on top of existing soil, often only 2 to 6 inches. Raised beds are empty containers that need full-depth fill, usually 6 to 24 inches.

That is why a 200 ft² garden refresh at 3 inches only needs 50 ft³ base volume, while a single 4x8 ft raised bed at 12 inches already needs 32 ft³.

Example 1: Standard 4x8 Raised Bed

A classic 4 x 8 ft raised bed, 12 inches deep.

Step 1: ft³ = 4 x 8 x 12 ÷ 12 = 32 ft³

Step 2: Add 10% overage = 35.2 ft³

Step 3: yd³ = 35.2 ÷ 27 = 1.30 yd³

Step 4: 2 cu ft bags = 35.2 ÷ 2 = 17.6, so buy 18 bags

Result: Order about 1.5 yd³ bulk soil or buy 18 x 2 cu ft bags.

Example 2: Three Raised Beds

Three 4 x 8 ft beds, each 12" deep.

Step 1: Single bed = 4 x 8 x 12 ÷ 12 = 32 ft³

Step 2: Three beds = 32 x 3 = 96 ft³

Step 3: Add 10% overage = 105.6 ft³

Step 4: yd³ = 105.6 ÷ 27 = 3.91 yd³

Result: Order 4 yd³ bulk topsoil instead of moving 50+ bags.

Example 3: Lawn Topdressing

Topdressing a 2,000 ft² lawn with 1/2 inch of screened topsoil.

Step 1: ft³ = 2,000 x 0.5 ÷ 12 = 83.3 ft³

Step 2: Add 10% overage = 91.7 ft³

Step 3: yd³ = 91.7 ÷ 27 = 3.40 yd³

Result: Order about 3.5 yd³ screened topsoil and apply in thin passes.

Soil Types - Choosing the Right Material

Different soil products solve different problems. Use the right one for the job instead of just the cheapest one.

🌱

Topsoil

Natural mineral soil with some organic matter, usually screened for rocks and debris.

Best for

  • • Garden beds
  • • Lawn topdressing
  • • Mixing into raised beds

Not ideal for

  • • Containers
  • • Standalone premium raised bed fill

Bulk: $25-$45/yd³

Bags: $4-$6 per 40 lb bag

🪴

Raised Bed Mix

Blended topsoil, compost, and aeration material for drainage, fertility, and lighter weight.

Best for

  • • Raised garden beds
  • • Large planters
  • • Vegetable beds

Not ideal for

  • • Large in-ground areas
  • • Budget fill projects

Bulk: $50-$80/yd³

Bags: $8-$12 per 1.5 cu ft bag

🌿

Garden Soil (Bagged)

Convenient pre-blended soil with compost or bark fines, made for in-ground planting beds.

Best for

  • • In-ground beds
  • • Topping up raised beds
  • • Flower borders

Not ideal for

  • • Containers
  • • Very large areas on a budget

Bulk: Usually bagged only

Bags: $5-$8 per 1.5 cu ft bag

🌺

Potting Mix

A soilless or mostly soilless blend that drains fast and stays lightweight in containers.

Best for

  • • Containers
  • • Window boxes
  • • Indoor plants
  • • Seed starting

Not ideal for

  • • In-ground planting
  • • Large raised beds on price-sensitive jobs

Bulk: Usually bagged only

Bags: $8-$15 per 1 cu ft bag

🌾

Compost

Decomposed organic matter that improves fertility, drainage, and moisture retention when mixed into soil.

Best for

  • • Soil amendment
  • • Annual topdressing
  • • Improving clay or sand

Not ideal for

  • • Standalone raised bed fill
  • • Structural grading

Bulk: $25-$45/yd³

Bags: $5-$8 per 1 cu ft bag

🏗️

Fill Dirt

Subsoil with very little organic matter, used where structure and compaction matter more than plant health.

Best for

  • • Grading and leveling
  • • Foundation backfill
  • • Building up low areas

Not ideal for

  • • Planting beds
  • • Raised beds
  • • Topdressing lawns

Bulk: $10-$25/yd³

Bags: Usually bulk only

Common Soil Projects - Volume Planning Guide

Six common soil scenarios with cubic feet estimates and buying notes.

🌱

First-Time Raised Bed Garden

Three 4 x 8 ft beds at 12 inches deep need 96 ft³ before overage or 105.6 ft³ after overage. That is nearly 4 cubic yards of material.

  • • About 53 x 2 cu ft bags if bagged
  • • Bulk is usually cheaper after 2 yd³
  • • Mix topsoil, compost, and aeration material for vegetables
  • • Expect 10-20% settling in the first season
🏡

Lawn Topdressing Project

A 5,000 ft² lawn at 1/4" depth needs 114.6 ft³ with overage. At 1/2", it jumps to 229.2 ft³, so thin depth control matters.

  • • Use screened topsoil or compost only
  • • Apply no more than 1/2" at once
  • • Fall and early spring are safest seasons
  • • Rake and brush material into the turf canopy
🌿

New In-Ground Vegetable Garden

Converting a 200 ft² lawn patch into a garden with a 6" fresh soil layer needs about 110 ft³ after overage, or 4.07 yd³.

  • • Loosen existing soil before adding new soil
  • • A 70/30 topsoil and compost mix is a strong starting point
  • • Annual 1" compost refresh needs only 16.7 ft³ before overage
  • • Bulk delivery simplifies large bed creation
🏗️

Yard Leveling & Grading

A 20 x 15 ft low area filled 6" deep needs 165 ft³ after overage. Using fill dirt for the lower layer and topsoil above cuts cost significantly.

  • • Use fill dirt for structure, topsoil for the plant zone
  • • Layering can save 30-50% versus all-topsoil fill
  • • Check drainage direction before raising grades
  • • Cap with 2-6 inches of plant-friendly soil where roots will grow
🌸

Front Yard Landscape Renovation

A 400 ft² front yard bed with 4" topsoil plus 2" compost ends up around 8.15 yd³ total across the two layers.

  • • Order both materials together if the supplier can blend or deliver once
  • • Topsoil handles mass volume, compost drives fertility
  • • Use this calculator twice when layers use different materials
  • • Bulk discounts often start around 5 yd³
🌳

Tree Planting & Backfill

Tree holes use less soil than people expect because the root ball displaces much of the space. Backfill planning is still useful for multiple trees.

  • • Five trees can still need more than 1.5 yd³ of backfill mix
  • • Blend compost into native soil instead of replacing everything
  • • Avoid pure potting mix in tree holes
  • • Keep finished soil grade level with the surrounding ground

Common Soil Volumes at a Glance

Click any card to pre-fill the calculator above.

Frequently Asked Questions

Common questions about calculating soil in cubic feet, cubic yards, and bags.

How do I calculate cubic feet of soil?
Use this formula: ft³ = Length(ft) x Width(ft) x Depth(in) ÷ 12 For a raised bed: ft³ = Length x Width x Height(in) ÷ 12 Examples: 4x8 ft bed at 12" = 32 ft³ 10x10 ft bed at 6" = 50 ft³ 1,000 ft² lawn at 1/2" = 41.7 ft³ Always add 10% for overage: 32 x 1.10 = 35.2 ft³ to order. At 12" depth, cubic feet equals square feet because 12 ÷ 12 = 1.
How many cubic feet of soil are in a cubic yard?
1 cubic yard = 27 cubic feet. Bulk soil and topsoil are usually sold by the cubic yard. How many raised beds does 1 yd³ fill? 4x4 ft at 12" = 16 ft³, so 1 yd³ fills 1.69 beds 4x8 ft at 12" = 32 ft³, so 1 yd³ fills 0.84 beds 4x8 ft at 6" = 16 ft³, so 1 yd³ fills 1.69 beds Coverage of 1 yd³ as a layer: At 1" = 324 ft² At 2" = 162 ft² At 3" = 108 ft² At 6" = 54 ft² At 12" = 27 ft² To convert your ft³ to yd³: yd³ = ft³ ÷ 27
How many bags of soil do I need for a raised bed?
For a standard 4x8 ft raised bed at 12" deep: 4 x 8 x 12 ÷ 12 = 32 ft³ With 10% overage = 35.2 ft³ Bag count by size: 2 cu ft bags = 18 bags 1.5 cu ft bags = 24 bags 1 cu ft bags = 36 bags 40 lb bags at 0.75 ft³ each = 47 bags Other common 12" raised beds: 4x4 ft = 16 ft³ base 4x6 ft = 24 ft³ base 4x8 ft = 32 ft³ base 4x12 ft = 48 ft³ base 4x16 ft = 64 ft³ base For 3 or more beds, bulk delivery usually wins on cost and labor.
How much does a cubic yard of topsoil cover?
1 cubic yard of topsoil covers: At 1/4" = 1,296 ft² At 1/2" = 648 ft² At 1" = 324 ft² At 2" = 162 ft² At 3" = 108 ft² At 6" = 54 ft² At 12" = 27 ft² Formula: ft² covered = 324 ÷ depth(in) To find cubic yards needed: yd³ = Area(ft²) x Depth(in) ÷ 324
How deep should soil be in a raised bed?
Recommended raised-bed depth: 6-8 inches: Lettuce, spinach, herbs, strawberries 10-12 inches: Tomatoes, peppers, cucumbers, beans This is the most common raised-bed depth 14-18 inches: Larger tomatoes, melons, and heavier feeders 18-24 inches: Carrots, parsnips, potatoes, deep-rooted crops If you are unsure, 12 inches works for most vegetable gardens.
What is the difference between topsoil and fill dirt?
Topsoil: Contains organic matter and nutrients Used for planting beds, lawn topdressing, and gardens Often costs $25-$45 per cubic yard Fill dirt: Mostly subsoil with little or no organic matter Used for grading, leveling, and structural fill Often costs $10-$25 per cubic yard Use fill dirt for the lower bulk layer and cap it with topsoil if plants will grow in the finished area.
Should I buy bagged soil or bulk topsoil delivery?
Use bagged soil when: You need less than 1-2 yd³ You only have one small raised bed You need a specific specialty mix Bulk delivery access is poor Use bulk delivery when: You need more than 2 yd³ You are filling multiple raised beds You are topdressing a lawn or large garden Cost savings matter Example comparison: 2 cu ft bags at $6 each = about $81 per yd³ Bulk topsoil often runs $30-$45 per yd³ Above roughly 2 yd³, bulk is usually 2x to 3x cheaper.

Your calculations deserve precision.

From cubic meters to cubic feet, compare volumes quickly with clear formulas and fast results.

Start Calculating