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Uniform Depth & Volume per Square Foot

Calculate the volume over a rectangular area and the volume per square foot from a uniform depth.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 10 ft by 10 ft area filled one foot deep holds about 748.05195 US gallons. The same depth corresponds to about 7.48052 US gallons per square foot.

Volume = area × uniform depth; US gallons per ft² = depth in feet × 1,728 ÷ 231

Worked example

Enter these known values and leave the other values blank.

Length
10 ft
Width
10 ft
Uniform depth
1 ft
Covered area
100 ft²
Volume
748 US gal
Volume per square foot
7.48 US gal / sq.ft / ft²

Assumptions and limitations

  • The area is flat and the depth is uniform. Enter a known area directly, or supply rectangular length and width. All dimensions, area and volume must be positive.
  • The per-area denominator stays one international square foot. Its selector changes the volume numerator only: liters per square foot and US gallons per square foot are different numeric representations of the same depth.
  • A US liquid gallon is exactly 231 cubic inches. One cubic foot contains 1,728 cubic inches. The optional acre uses 43,560 international square feet.
  • This is geometry, not a rainfall-runoff, drainage, permeability or load-capacity model. Voids, slopes, absorption and displacement are not added automatically.

Common questions

How much is one inch of depth over one square foot?

One inch over a square foot is 144 cubic inches. Dividing by 231 gives about 0.623377 US gallons per square foot.

Does selecting liters also change the area denominator?

No. The per-area field remains per square foot. Its volume selector changes only the numerator; the label keeps the denominator visible.

References

The international acre is exactly 43560 square international feet; Bookify replaces the rounded captured area factor. Bookify replaces the captured rounded US gallon with the exact 3.785411784-liter definition. The US fluid ounce uses one 128th of the exact US liquid gallon, replacing the rounded captured reciprocal factor.

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