Cubic Feet to Quarts Soil Calculator

This calculator converts a volume of soil measured in cubic feet to quarts, and also shows the equivalent in gallons and liters. You enter the cubic feet value, and it returns the number of quarts (US liquid quarts) of soil, which is the standard unit for bagged soil sold in garden centers. The conversion is based on the fixed relationship: 1 cubic foot = 25.714 US quarts.

Formula

The core conversion is:

Quarts = Cubic feet × 25.714

Where:

• Cubic feet (ft³) – the volume you want to convert (the number you enter).
• Quarts (qt) – the resulting volume in US liquid quarts.
• 25.714 – the exact number of US liquid quarts in one cubic foot (derived from 1 ft³ = 1,728 in³ and 1 US quart = 57.75 in³).

For reference, 1 cubic foot also equals 7.48052 US gallons and 28.3168 liters.

Worked Example

Using the default value of 1.5 cubic feet:

1. Multiply: 1.5 × 25.714 = 38.571
2. Rounded to one decimal place: 38.6 quarts

The calculator also shows:
1.5 × 7.48052 = 11.2 gallons
1.5 × 28.3168 = 42.5 liters

So a 1.5 ft³ bag of potting soil holds about 38.6 quarts, or roughly 11.2 gallons.

Why Soil Volume Units Matter

Bagged soil is typically sold by volume, not weight. In the United States, most commercial potting mixes are labeled in cubic feet (e.g., 1.5 ft³, 2 ft³) or quarts (e.g., 8 qt, 16 qt, 32 qt). Understanding the conversion helps you compare prices and know exactly how much soil you need for a container or raised bed.

One common confusion is that “quarts� in soil bags are US liquid quarts, not dry quarts or imperial quarts. The US liquid quart is the standard used by soil manufacturers. (A dry quart is about 1.16 times larger, but you’ll rarely see it on soil bags.)

How to Choose the Right Bag Size

To figure out how many bags to buy, first calculate the volume of your planter or bed in cubic feet:

• Rectangular bed: length (ft) × width (ft) × depth (ft) = cubic feet.
• Round pot: Ï€ × radius² × height (all in feet) = cubic feet.
• Raised bed: treat it as a rectangular box, using the depth of soil you plan to fill.

Then divide that number by the bag size in cubic feet (e.g., 1.5 ft³ or 2 ft³) to get the number of bags. If you prefer quarts, multiply the cubic feet by 25.714 to get quarts, then divide by the quart size of the bag (e.g., 8 qt, 16 qt).

For example, a 4 ft × 2 ft × 1 ft raised bed holds 8 ft³. That equals 8 × 25.714 = 205.7 quarts. If you buy 16-quart bags, you need 205.7 ÷ 16 ≈ 12.9, so 13 bags.

Common Mistakes and Misconceptions

• Mixing up gallons and quarts: 1 gallon = 4 quarts, but 1 cubic foot = 7.48 gallons, so 1 cubic foot = about 29.9 quarts (not 4). The 25.714 factor already accounts for the cubic-inch difference.
• Using dry quarts: Some older references use US dry quarts (1 ft³ ≈ 25.71 dry quarts, actually slightly different). Stick with liquid quarts for soil bags; it’s the industry standard.
• Ignoring settling: Soil compresses when watered. It’s wise to buy 10–15% extra to top off after settling.
• Weight vs. volume: A cubic foot of dry soil weighs about 40–50 pounds, but weight varies with moisture and composition. Always buy by volume, not weight.

Cost and Comparison Tips

When comparing prices, convert every bag to a common unit (quarts or cubic feet). For instance, a 1.5 ft³ bag is 38.6 quarts, while a 16-quart bag is only 0.62 ft³. The larger bag usually costs less per quart, but check the price per quart to be sure.

Also note that “potting mix� and “garden soil� are different products. Potting mix is lighter and formulated for containers; garden soil is heavier and meant for in-ground use. The volume conversion is the same, but the suitability differs.

Safety and Accuracy Notes

There are no safety hazards in volume conversion, but accuracy matters for plant health. Overfilling a container with soil can block drainage; underfilling leaves roots exposed. Always measure the interior dimensions of your planter (not the outside) and subtract any rocks or drainage material at the bottom.

For large raised beds, consider buying soil in bulk (by cubic yard) instead of bags. One cubic yard equals 27 cubic feet, or about 694 quarts. Bulk soil is often cheaper but requires delivery or pickup.

Frequently Asked Questions

How many quarts are in a 2 cubic foot bag of soil?

Multiply 2 × 25.714 = 51.4 quarts. A 2 ft³ bag holds about 51 quarts (or 12.8 gallons).

Is 1 cubic foot the same as 1 quart?

No. 1 cubic foot is much larger: it equals 25.714 quarts. A quart is about 0.0389 cubic feet.

Why do soil bags list both quarts and cubic feet?

Manufacturers list both to help consumers compare. Quarts are familiar for small pots, while cubic feet is standard for larger volumes. The conversion is fixed, so you can use either.

How much soil do I need for a 5-gallon bucket?

A 5-gallon bucket holds about 0.67 cubic feet (since 1 gallon = 0.1337 ft³). That equals 0.67 × 25.714 ≈ 17.2 quarts. A typical 16-quart bag is almost enough, but you’ll need a bit more to fill to the rim.

Does the calculator work for raised beds?

Yes, as long as you know the bed’s volume in cubic feet. Measure length, width, and depth in feet, multiply them, then enter that number.

What about metric soil bags?

If your soil is sold in liters, use the liters output. 1 cubic foot = 28.3168 liters. For example, 1.5 ft³ = 42.5 liters, which is close to a 45-liter bag.

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in ft3 | Cubic feet of soil | ft³ | 1.5 | 0
out qt | Volume in quarts | qt | ft3 * 25.714 | 1
out gal | Volume in gallons | gal | ft3 * 7.48052 | 1
out L | Volume in liters | L | ft3 * 28.3168 | 1