Gallons per Square Foot Calculator

Use this gallons per square foot calculator to convert between area, depth, and water volume. It is a practical way to estimate how much water a pool, tank, basin, or coated surface will hold when you know the footprint and fill depth.

ft2
ft
gal
gal/ft2

Result

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Quick Answer: One cubic foot of water contains 7.48052 gallons. Multiply the depth in feet by 7.48052 to get gallons per square foot, then multiply by area to get total gallons. Divide if you want the area or the depth instead.

What This Gallons per Square Foot Calculator Helps You Do

Use this gallons per square foot calculator to convert between area, depth, and water volume. It is a practical way to estimate how much water a pool, tank, basin, or coated surface will hold when you know the footprint and fill depth.

How to Calculate Gallons per Square Foot Calculator

  1. Choose the value you know - Start with the area, the depth, or the total gallons depending on the situation.
  2. Keep the units consistent - Use feet for depth and square feet for area so the conversion stays simple.
  3. Let the calculator convert - The calculator applies the gallon-per-cubic-foot conversion automatically.
  4. Use the result for planning - Read the gallons per square foot, total gallons, or required area depending on the mode.

Gallons per Square Foot Calculator Formula

Gallons = area × depth × 7.48052
Symbol Definition Unit
Area Surface area ft2
Depth Water depth ft
7.48052 Gallons in one cubic foot of water gal/ft3

Worked Examples

USA - Pool fill depth
  • area: 240
  • depth: 0.333
  • gallons: 0
  • gpsf: 0

Result: Gallons = 597.84 gal

Each square foot holds a measurable amount of water at this depth. The estimate is 597.84 gal.

UK - Aquarium base area
  • area: 0
  • depth: 1
  • gallons: 80
  • gpsf: 0

Result: Area = 10.69 ft2

A one-foot depth lets you back into the required footprint from the gallons figure. The estimate is 10.69 ft2.

EU - Pond volume check
  • area: 150
  • depth: 0.5
  • gallons: 0
  • gpsf: 0

Result: Gallons = 561.04 gal

The pond volume is simply area multiplied by depth and then converted to gallons. The estimate is 561.04 gal.

GCC - Coating coverage
  • area: 100
  • depth: 0
  • gallons: 20
  • gpsf: 0

Result: Depth = 0.03 ft

Spreading a small gallon count over a known area produces a shallow coating depth. The estimate is 0.03 ft.

How to Interpret Your Results

Range Meaning Action
Shallow depth Low gallons per square foot Good for thin coatings, small pond depths, or shallow holding basins.
Moderate depth Typical water coverage Useful for pool fills, tanks, and general volume estimates.
Greater depth Higher gallons per square foot Check containment, weight loading, and fill capacity before proceeding.

Frequently Asked Questions

It estimates the main planning quantity for gallons per square foot work using the formula shown on the page. That gives you a practical number before you order materials, compare suppliers, or talk to a contractor. The gallon-per-square-foot value changes only with depth, because the area cancels once the volume is converted.

Enter the values that match the unit labels beside the fields. If the page expects feet, inches, gallons, pounds, or watts, keep everything in that unit family so the result stays reliable.

The calculator multiplies or divides the main quantity by the values you enter, so every measurement feeds directly into the final answer. A small change in depth, area, density, or factor can make a large difference on a bigger project.

Yes, as long as the units stay consistent within the calculation. If the page expects feet, inches, gallons, or pounds, convert first so the final result is accurate and easy to interpret.

Treat the result as a planning estimate. Use the main output for sizing or ordering, then review the detail rows for waste, weight, cost, or conversion notes before you finalize the purchase.

Yes if the job involves cut losses, uneven ground, spill risk, or irregular shapes. A small allowance is usually safer than ordering exactly to the bare math, especially for gallons per square foot projects that are hard to top up later.

It is exact for the numbers you enter, but real-world projects can still vary because of compaction, tolerances, site conditions, and product differences. Use the result as a solid working estimate, not a final structural or procurement check.

Yes. That is one of its main uses. The result helps you estimate how much to buy, what it may weigh, and what the budget might look like before you place an order or request a quote.
Disclaimer: This is a conversion estimate for planning purposes. Real-world fill volumes can vary slightly because of surface irregularity, evaporation, or material displacement.

Sources

Last reviewed: March 2026