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Same water. Clearer units.

Translate volume, flow or height into a unit you can use. Choose a measurement, enter a value and see the conversion factor.

1 Acre-feet equals325,851.429US liquid gallons

Multiply by 325,851.429. Display rounded to nine significant digits.

Signed values are accepted for heights and changes. Changing units does not change the reference datum or turn a height into water volume.

A worked example

One acre-foot is 43,560 cubic feet. Using the international foot and US liquid gallon, that is about 325,851.429 gallons. Ten acre-feet is about 3,258,514.29 gallons.

One cubic foot per second is about 448.831169 US gallons per minute. This describes a rate; it is not a stored volume.

How the calculation works

Result = input × source factor ÷ destination factor. Factors use metres, cubic metres or cubic metres per second as the intermediate unit. Calculations retain the factors’ precision; displayed results are rounded.

One international foot is exactly 0.3048 metres. One US liquid gallon is 0.003785411784 cubic metres. An acre-foot here uses 43,560 international cubic feet.

Common questions

Can I convert feet of lake-level change to gallons?

Not from height alone. Reservoir shape and its elevation–storage relationship are needed. Use our guide to elevation and storage before comparing them.

Does converting feet to metres change the datum?

No. It changes the unit only. A gauge-height reading, reservoir elevation and tidal height can use different reference surfaces even when all are expressed in metres.

Are these imperial gallons or survey feet?

No. The converter uses US liquid gallons and the international foot. Historical survey-foot measurements need their original unit definition.

Sources and next steps

Explore actual lake changes → · Understand stage and discharge → · All tools →