How to Calculate Soil for Your Garden

Whether you're building a new raised garden bed, filling a planter, or topping up an existing area, figuring out how much soil you need is the first step. Our Garden Soil Calculator simplifies this process, but understanding the basic formula is helpful for any gardener.

The Soil Volume Formula

The calculation for the volume of soil needed is a simple formula: Volume = Length × Width × Depth. The key is to ensure all your measurements are in the same unit before multiplying.

For Imperial Measurements (feet, inches):

1. Measure the length and width of your garden bed in feet.
2. Measure the desired depth of your soil in inches.
3. Convert the depth from inches to feet by dividing by 12 (e.g., 12 inches is 1 foot).
4. Multiply the three dimensions together: Length (ft) × Width (ft) × Depth (ft). The result is the volume in cubic feet.

For Metric Measurements (meters, cm):

1. Measure the length and width of your garden bed in meters.
2. Measure the depth in centimeters.
3. Convert the depth from centimeters to meters by dividing by 100 (e.g., 30cm is 0.3 meters).
4. Multiply the three dimensions together: Length (m) × Width (m) × Depth (m). The result is the volume in cubic meters.

Remember that soil is often sold in bags measured in cubic feet or liters. One cubic meter is equal to 1000 liters. It's often a good idea to buy slightly more than you calculate to account for settling.