Acre Feet to Cubic Yards Conversion

One acre foot equals 1,613.333… cubic yards (1,613 1/3 yd³). To convert acre feet to cubic yards, multiply the number of acre feet by 1,613.333, or more precisely by 1,613.333333. This article explains the conversion, shows the math, and gives you a calculator to do it instantly.

Formula

The conversion relies on the definitions of both units:

• 1 acre foot = 43,560 cubic feet (the volume of 1 acre of area, 1 foot deep).
• 1 cubic yard = 27 cubic feet (3 feet × 3 feet × 3 feet).

Therefore:

Cubic yards = Acre feet × 43,560 / 27

Since 43,560 ÷ 27 = 1,613.333…, the simplified formula is:

Cubic yards = Acre feet × 1,613.333

Where acre feet is the volume you start with (unit: ac ft) and cubic yards is the result (unit: yd³).

Worked Example

Using the calculator defaults (1 acre foot):

1. Start with 1 acre foot.
2. Convert to cubic feet: 1 × 43,560 = 43,560 ft³.
3. Divide by 27 to get cubic yards: 43,560 ÷ 27 = 1,613.333… yd³.

So 1 acre foot = 1,613.33 cubic yards (rounded to two decimals). The calculator shows 1,613.33 yd³, matching the example.

Why This Conversion Matters

Acre feet are used almost exclusively for large water volumes—reservoir capacities, irrigation water allocations, and flood control. Cubic yards are the standard unit for earthwork, concrete, and fill dirt. If you’re a farmer ordering soil for a field, a contractor planning a pond, or a water district reporting deliveries, you may need to switch between these units. The conversion is exact and never changes, so you can rely on it.

How to Do It Without a Calculator

You can do the math by hand in two steps:

1. Multiply the acre feet by 43,560 to get cubic feet.
2. Divide that number by 27 to get cubic yards.

For quick mental estimates, remember that 1 acre foot is roughly 1,600 cubic yards. For precise work, use 1,613.333.

Common Mistakes and How to Avoid Them

• Mixing up acre feet and acre-inches: One acre-inch is 1/12 of an acre foot. If you have acre-inches, divide by 12 first.
• Forgetting that a cubic yard is 27 cubic feet, not 3: This is the most common error. Always divide by 27, not 3.
• Rounding too early: If you round 43,560/27 to 1,613 before multiplying, you lose precision. Keep the full decimal until the end.
• Using the wrong conversion factor: Some sources give 1 acre foot = 1,613.33 yd³, others 1,613.333. Use the latter for accuracy.

Real-World Examples

• Pond excavation: A 2-acre pond with an average depth of 5 feet holds 10 acre feet. That’s 10 × 1,613.333 = 16,133.33 cubic yards of water volume.
• Irrigation canal: A canal that delivers 0.5 acre feet per day to a farm moves 0.5 × 1,613.333 = 806.67 cubic yards of water daily.
• Reservoir storage: A small reservoir with 50 acre feet of capacity holds 50 × 1,613.333 = 80,666.65 cubic yards.

Limits of the Formula

The conversion is pure mathematics and always accurate. The only limits come from measurement: an “acre foot� assumes a perfectly flat acre with uniform depth. Real ponds, reservoirs, and fields have irregular shapes, so the measured volume may differ from the calculated one. Also, water volume changes slightly with temperature and pressure, but for practical purposes the conversion is exact.

Frequently Asked Questions

How many cubic yards are in an acre foot?

Exactly 43,560/27 cubic yards, which equals 1,613.333… yd³. Rounded to two decimals, it’s 1,613.33.

How do I convert cubic yards back to acre feet?

Divide the number of cubic yards by 1,613.333. For example, 3,226.67 cubic yards ÷ 1,613.333 = 2 acre feet.

What is an acre foot used for?

It’s used to measure large water volumes, especially in agriculture, water rights, and reservoir management. One acre foot is enough water to cover one acre of land one foot deep.

Is an acre foot the same as an acre-inch?

No. An acre-inch is 1/12 of an acre foot. To convert acre-inches to cubic yards, multiply by 134.444 (since 1,613.333/12 = 134.444).

How many gallons are in an acre foot?

There are 325,851.429 US gallons in one acre foot (43,560 ft³ × 7.48052 gal/ft³). The calculator shows this as a secondary output.

Why is the conversion factor not a round number?

Because an acre foot is defined as 43,560 cubic feet (based on the acre, which is 43,560 square feet), and a cubic yard is 27 cubic feet. Dividing 43,560 by 27 gives a repeating decimal.

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in af | Acre feet | ac ft | 1 | 0
out yd3 | Cubic yards | yd³ | af * 1613.333333 | 2
out ft3 | Cubic feet | ft³ | af * 43560 | 0
out gal | US gallons | gal | af * 325851.428571 | 0