To convert acre-feet per day to US gallons per day, multiply by 325,851.4958. That factor is the whole relationship: both units measure volumetric flow, so the conversion is a proportion with no offset and no substance-specific constant.
Irrigation and reservoir release rates in the western United States. The rating unit for reverse-osmosis membranes and water demand.
Standard versus actual volume. Gas flow in CFM depends on pressure and temperature, which is why compressor ratings say SCFM and specify the reference conditions. Converting the number is exact; comparing two ratings measured at different conditions is not. Two tables follow: rounded steps for quick lookup, and a set of real reference quantities converted into US gallons per day, which is usually more useful than the bare number.
The formula
acre-feet per day- The amount you are converting, in acre-feet per day
325,851.49576- The exact number of US gallons per day in one acre-foot per day
US gallons per day- The converted result
How it works, step by step
- Enter the value in acre-feet per day.
- It is multiplied by 325,851.49576, the exact factor between the two units.
- The answer is shown in US gallons per day, with the reverse conversion beneath it.
- Check the reference table if you want a figure of comparable size.
Worked examples
A bathroom tap: 0.007 ac ft/d in US gallons per day
At 0.007 ac ft/d (a bathroom tap), the same quantity in US gallons per day is 0.007 × 325,851 = 2280.96 GPD. One acre-foot per day is 325,851 US gallons per day, so the numbers grow as expected.
A garden hose: 0.021 ac ft/d in US gallons per day
A garden hose comes to about 0.021 ac ft/d. Multiplying by the factor: 0.021 × 325,851 = 6842.88 GPD. Dividing the answer back by 325,851 returns the figure you started with, which is the quickest way to check you have the factor the right way up.
How to read your score
Frequently asked questions
How many US gallons per day are in one acre-foot per day?
Exactly 325,851.49576. Every figure on this page is that one number multiplied by your input, so the only rounding is at the display step.
What is the formula to convert acre-feet per day to US gallons per day?
US gallons per day = acre-feet per day × 325,851.49576. Reversed, acre-feet per day = US gallons per day ÷ 325,851.49576, which is the same as multiplying by 3.06888264443e-06.
Which is the bigger unit, the acre-foot per day or the US gallon per day?
The acre-foot per day. One acre-foot per day equals 325,851 US gallons per day.
What does this quantity actually measure?
Both units measure volumetric flow. That is why a single factor is enough: there is no temperature offset and no material property involved, unlike conversions that cross between different quantities.
What is a acre-foot per day?
Irrigation and reservoir release rates in the western United States.
What is a US gallon per day?
The rating unit for reverse-osmosis membranes and water demand.
Why does my answer differ from another converter?
Almost always because the other tool rounded the factor before multiplying. This page keeps full double precision through the calculation and rounds only for display, and it prints the factor it used so you can see where any difference came from.
Is there a quick way to do ac ft/d to GPD in my head?
Plenty of people do this in their head: multiply by 330,000 instead of using the exact factor 325,851.4958. At 100 that shortcut gives 33,000,000 US gallons per day, off by 414850.424005 US gallons per day or about 1.27%. Fine for a rough estimate, not fine for anything you are cutting to size or dosing.
Acre-Feet Per Day to US gallons per day reference tables
| Acre-Feet Per Day | Us Gallons Per Day |
|---|---|
| 0.5 ac ft/d | 162,926 GPD |
| 1 ac ft/d | 325,851 GPD |
| 2 ac ft/d | 651,703 GPD |
| 3 ac ft/d | 977,554 GPD |
| 5 ac ft/d | 1.62926e+06 GPD |
| 10 ac ft/d | 3.25851e+06 GPD |
| 20 ac ft/d | 6.51703e+06 GPD |
| 25 ac ft/d | 8.14629e+06 GPD |
| 50 ac ft/d | 1.62926e+07 GPD |
| 75 ac ft/d | 2.44389e+07 GPD |
| 100 ac ft/d | 3.25851e+07 GPD |
| 250 ac ft/d | 8.14629e+07 GPD |
| 500 ac ft/d | 1.62926e+08 GPD |
| 1000 ac ft/d | 3.25851e+08 GPD |
| 5000 ac ft/d | 1.62926e+09 GPD |
Exact factor: 1 acre-foot per day = 325,851.49576 US gallons per day.
| Quantity | ac ft/d | GPD |
|---|---|---|
| A dripping tap | 7.005e-06 ac ft/d | 2.282 GPD |
| A bathroom tap | 0.007005 ac ft/d | 2282 GPD |
| A shower head | 0.01121 ac ft/d | 3652 GPD |
| A garden hose | 0.02101 ac ft/d | 6847 GPD |
| A fire hydrant | 4.203 ac ft/d | 1.369e+06 GPD |
| The Thames at London | 4553 ac ft/d | 1.484e+09 GPD |
Published reference values, converted with the same factor this page uses.