Soil Cubic Feet Calculator

If you’re planning a landscaping project, starting a new garden bed, or filling raised planters, one critical step is estimating how much soil you’ll need. That’s where the Soil Cubic Feet Calculator becomes an essential tool. This online calculator helps you quickly determine the volume of soil needed for any space, ensuring that you neither overbuy nor fall short.

Soil Cubic Feet Calculator
* Calculation: Volume = Length × Width × (Depth ÷ 12).
Bags are estimated using 1.5 cubic feet per bag.

📌 What is a Soil Cubic Feet Calculator?

The Soil Cubic Feet Calculator is a digital tool designed to compute the volume of soil needed to fill a specific area, expressed in cubic feet. This is crucial for gardeners, landscapers, and DIY enthusiasts who want to avoid waste and optimize their soil purchases.

The calculator considers the length, width, and depth of your soil bed or planter box and returns the total volume in cubic feet — the standard unit used by most soil suppliers.


🧑‍🌾 How to Use the Soil Cubic Feet Calculator

Using the tool is simple and user-friendly. Follow the steps below:

  1. Measure the area you want to fill (typically in feet).
    • Length (in feet)
    • Width (in feet)
    • Depth or Height (in inches or feet)
  2. Enter the values into the calculator:
    • If depth is in inches, the calculator will auto-convert to feet.
  3. Click "Calculate" to get the total soil volume in cubic feet.
  4. Optionally, the result may show:
    • Cubic yards (for large orders)
    • Number of soil bags needed (if bag size is known)

📐 Formula Used in Soil Cubic Feet Calculator

The calculator uses a basic volume formula, but with a conversion if depth is entered in inches.

Formula (when all dimensions are in feet):

mathematicaCopyEditVolume (cubic feet) = Length (ft) × Width (ft) × Depth (ft) 

Formula (when depth is in inches):

mathematicaCopyEditVolume (cubic feet) = Length (ft) × Width (ft) × (Depth (in) ÷ 12) 

This allows flexibility for users who may have measurements in both inches and feet.


🌿 Real-Life Example

Scenario: You’re planning to fill a raised garden bed that is:

  • Length = 6 feet
  • Width = 4 feet
  • Depth = 12 inches

Step 1: Convert the depth to feet
12 inches ÷ 12 = 1 foot

Step 2: Apply the formula
6 × 4 × 1 = 24 cubic feet

✅ You’ll need 24 cubic feet of soil to fill this garden bed.


🔄 Soil Volume Conversion Table

Cubic FeetCubic Yards1.5 cu ft Bags2 cu ft Bags
27 cu ft1 cu yd18 bags13.5 bags
54 cu ft2 cu yd36 bags27 bags
81 cu ft3 cu yd54 bags40.5 bags

💡 Most garden soil is sold in 1.5 or 2 cubic foot bags.


💡 Helpful Tips for Soil Calculation

  • Round up slightly to account for soil settling.
  • For irregular shapes, break the area into rectangles or circles and calculate individually.
  • Check with your soil supplier if they sell in cubic yards, so you can convert cubic feet accordingly:
    • 1 cubic yard = 27 cubic feet
  • Consider a mix of topsoil, compost, and manure if you're filling beds for vegetables or flowers.

✅ Applications of Soil Cubic Feet Calculator

  • Raised garden beds
  • Planter boxes
  • Lawn topdressing
  • Mulch and compost estimation
  • Filling holes or leveling ground
  • Flowerbeds and landscape edging

🧠 Why Accurate Soil Measurement Matters

Accurate soil estimation avoids:

  • Overbuying, which increases cost and storage hassle.
  • Underbuying, which delays your project.
  • Poor plant health due to insufficient root depth.

This calculator ensures cost-efficiency and project accuracy.


❓ 20 Frequently Asked Questions (FAQs)

1. What is a cubic foot in gardening terms?

A cubic foot is a volume measurement equal to a cube with sides of 1 foot. It's used to measure soil, mulch, and compost.

2. How many bags of soil do I need for 1 cubic foot?

You need one 1 cu ft bag or about two-thirds of a 1.5 cu ft bag.

3. How many cubic feet are in a cubic yard?

There are 27 cubic feet in one cubic yard.

4. What’s the depth of a typical raised garden bed?

Most raised beds are 6 to 12 inches deep, though deeper ones go up to 18 or 24 inches.

5. Can I input inches into the calculator?

Yes. Most calculators allow depth input in inches and convert automatically.

6. How accurate is the soil calculator?

Very accurate if measurements are correct. Always round up for safety.

7. Can I use this calculator for mulch or gravel?

Yes, it works for any material measured by volume.

8. What unit does the calculator output?

It outputs in cubic feet, sometimes with cubic yards and bags as additional info.

9. How do I convert cubic feet to cubic yards?

Divide cubic feet by 27.
Example: 54 cu ft ÷ 27 = 2 cu yd.

10. How many 2 cu ft bags in a cubic yard?

13.5 bags of 2 cu ft each make 1 cubic yard.

11. Is soil sold by cubic foot or yard?

Retail: cubic foot bags. Bulk: cubic yards.

12. How much does a cubic foot of soil weigh?

Moist soil: ~75–100 lbs per cubic foot.

13. Can I use metric units?

Use a converter to switch from feet to meters or inches to centimeters before input.

14. Does this calculator consider soil compaction?

No, but you can add 10–15% to account for compaction over time.

15. Can I reuse the calculator for multiple beds?

Yes. Just input each bed’s dimensions and total the results.

16. Is the tool mobile-friendly?

Most modern calculators are responsive for use on mobile devices.

17. Can I save my results?

Some versions allow you to print or email your result for later use.

18. Can I calculate for round planters?

Yes, if the calculator supports cylindrical shapes. Else use:
π × radius² × height.

19. What’s better — buying bags or bulk soil?

Bags are convenient for small projects; bulk is cheaper for large areas.

20. Does the calculator show cost estimation?

Some versions may let you enter cost per cubic foot or bag for budgeting.


🌼 Final Thoughts

A Soil Cubic Feet Calculator is a practical, time-saving tool for homeowners, gardeners, and landscapers alike. By eliminating guesswork, it ensures precise volume estimation for any soil-filling task. Whether you're planning a raised bed, leveling out your lawn, or preparing a large garden, this calculator will help you stay efficient and cost-effective.