What Is Acre-Inch?
An acre inch is a unit used to measure volume, especially water used on farms. It means enough water to cover one acre of land to a depth of one inch.
Farmers and water managers use the acre inch to plan how much water is needed to grow crops or to fill canals and ponds on farmland.
Definition
An acre inch is the volume of water that covers:
- an area of 1 acre
- to a depth of 1 inch
In common volume units, one acre inch is about:
- 3,630 cubic feet
- 102.8 cubic meters
- 102,800 liters of water
- 27,150 US gallons of water, approximately
There are 12 acre inches in one acre foot. So:
- 1 acre inch equals 1 divided by 12 of an acre foot
- 12 acre inches equal 1 acre foot
History / Origin
The acre inch grew out of farming needs in places that used the acre as a land unit, such as the United States and some other English speaking regions.
Farmers needed a simple way to talk about how much water was being spread over a field. They already measured land in acres and water depth in inches. Putting these together made the acre inch a natural and easy unit for irrigation planning.
As irrigation systems, dams, and canals were built in the 19th and 20th centuries, engineers and water agencies started using both the acre inch and the acre foot to talk about stored and delivered water.
Symbol & Abbreviation
The acre inch is usually written in a few short forms:
- ac in
- acre in
- sometimes written in full as acre inch
All of these mean the same thing. It is not an official SI unit, but it is widely understood in irrigation and water management.
Current Use Around the World
The acre inch is still used mainly in countries where land is often measured in acres, for example:
- The United States
- Parts of Canada
- Some regions of India, Pakistan, and a few other countries that still use acres for farmland
Typical uses include:
- Irrigation planning for crops such as corn, wheat, cotton, and vegetables
- Water delivery records by irrigation districts and water companies
- Estimating rainfall storage on fields when rain is measured in inches
In science and most engineering, people prefer metric units such as cubic meters or liters. Still, the acre inch remains popular with many farmers because it matches the way they think about their land and water depth.
Example Conversions
These examples show how an acre inch compares to other units.
| Amount | In Acre Inches | In Other Units |
|---|---|---|
| 1 acre inch of water | 1 ac in |
about 3,630 cubic feet about 102.8 cubic meters about 102,800 liters about 27,150 US gallons |
| 1 acre foot of water | 12 ac in |
about 43,560 cubic feet about 1,233 cubic meters |
| 6 acre inches | 6 ac in |
half an acre foot about 616,800 liters |
| Rain on 1 acre, 2 inches deep | 2 ac in | about 205,600 liters of water |
Simple rules you can remember:
- Multiply acre inches by 12 to get acre feet
- Divide acre feet by 12 to get acre inches
Related Units
The acre inch is closely linked to these other units:
- Acre foot a larger volume unit used for reservoirs and lakes, 1 acre foot equals 12 acre inches
- Acre a unit of area, often used for farmland, 1 acre is about 4,047 square meters
- Cubic foot a volume unit in the US customary system
- Cubic meter the main metric volume unit used in science and engineering
- Liter a common metric volume unit, 1 cubic meter equals 1,000 liters
- US gallon a volume unit used in the United States for liquids like water and fuel
FAQs
What is an acre inch in simple words
An acre inch is the amount of water that would cover a piece of land that is one acre in size with water that is one inch deep.
How many acre inches are in an acre foot
There are 12 acre inches in one acre foot. An acre foot is the volume of water that covers one acre to a depth of one foot.
Is an acre inch a metric unit
No, the acre inch is not a metric unit. It belongs to the US customary and older English system. The metric equivalent is usually given in cubic meters or liters.
How many liters are in one acre inch
One acre inch is about 102,800 liters of water.
How many US gallons are in one acre inch
One acre inch is about 27,150 US gallons of water.
Who uses acre inches today
Acre inches are mainly used by farmers, irrigation districts, and water managers in countries that measure land in acres, such as the United States.
Why use acre inches instead of cubic meters
For many farmers, acres and inches match the way they already measure their fields and water depth. Acre inches make it easy for them to picture how much water is going onto their land, even though cubic meters are better for scientific work.
Can I convert acre inches to cubic meters
Yes. To convert acre inches to cubic meters, multiply the number of acre inches by about 102.8. For example, 3 acre inches is about 308.4 cubic meters.
