Convert US gallons to US fluid ounces in one step. Results update live in both directions, with a worked formula, nearby units and a 1–100 chart you can click.
gal
fl oz
Step-by-step calculation
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How to use the Gallons to Ounces Converter
Type a value in the Gallons (US) box. The fluid ounces (US) result appears instantly.
Going the other way? Type in the Fluid ounces (US) box, or press the ⇄ swap button.
Set the precision with the decimal places menu.
Check the working in the step-by-step box, then press Copy result or click any row in the tables below.
Gallons (US) to fluid ounces (US) formula
fl oz = gal × 128
Take the value in US gallons.
Multiply it by 128 (the number of US fluid ounces in one US gallon).
Example: 1 gal × 128 = 128 fl oz.
Reverse formula (US fluid ounces to US gallons): gal = fl oz ÷ 128. Example: 1,536 fl oz ÷ 128 = 12 gal.
The factor is a whole number (128), so this one is easy to do in your head.
gal to fl oz conversion table (1–100)
Click any row to load it into the converter.
Gallons (US) to fluid ounces (US)
Gallons (US)
Fluid ounces (US)
1 gal
128 fl oz
2 gal
256 fl oz
3 gal
384 fl oz
4 gal
512 fl oz
5 gal
640 fl oz
6 gal
768 fl oz
7 gal
896 fl oz
8 gal
1,024 fl oz
9 gal
1,152 fl oz
10 gal
1,280 fl oz
11 gal
1,408 fl oz
12 gal
1,536 fl oz
13 gal
1,664 fl oz
14 gal
1,792 fl oz
15 gal
1,920 fl oz
16 gal
2,048 fl oz
17 gal
2,176 fl oz
18 gal
2,304 fl oz
19 gal
2,432 fl oz
20 gal
2,560 fl oz
21 gal
2,688 fl oz
22 gal
2,816 fl oz
23 gal
2,944 fl oz
24 gal
3,072 fl oz
25 gal
3,200 fl oz
26 gal
3,328 fl oz
27 gal
3,456 fl oz
28 gal
3,584 fl oz
29 gal
3,712 fl oz
30 gal
3,840 fl oz
31 gal
3,968 fl oz
32 gal
4,096 fl oz
33 gal
4,224 fl oz
34 gal
4,352 fl oz
35 gal
4,480 fl oz
36 gal
4,608 fl oz
37 gal
4,736 fl oz
38 gal
4,864 fl oz
39 gal
4,992 fl oz
40 gal
5,120 fl oz
41 gal
5,248 fl oz
42 gal
5,376 fl oz
43 gal
5,504 fl oz
44 gal
5,632 fl oz
45 gal
5,760 fl oz
46 gal
5,888 fl oz
47 gal
6,016 fl oz
48 gal
6,144 fl oz
49 gal
6,272 fl oz
50 gal
6,400 fl oz
51 gal
6,528 fl oz
52 gal
6,656 fl oz
53 gal
6,784 fl oz
54 gal
6,912 fl oz
55 gal
7,040 fl oz
56 gal
7,168 fl oz
57 gal
7,296 fl oz
58 gal
7,424 fl oz
59 gal
7,552 fl oz
60 gal
7,680 fl oz
61 gal
7,808 fl oz
62 gal
7,936 fl oz
63 gal
8,064 fl oz
64 gal
8,192 fl oz
65 gal
8,320 fl oz
66 gal
8,448 fl oz
67 gal
8,576 fl oz
68 gal
8,704 fl oz
69 gal
8,832 fl oz
70 gal
8,960 fl oz
71 gal
9,088 fl oz
72 gal
9,216 fl oz
73 gal
9,344 fl oz
74 gal
9,472 fl oz
75 gal
9,600 fl oz
76 gal
9,728 fl oz
77 gal
9,856 fl oz
78 gal
9,984 fl oz
79 gal
10,112 fl oz
80 gal
10,240 fl oz
81 gal
10,368 fl oz
82 gal
10,496 fl oz
83 gal
10,624 fl oz
84 gal
10,752 fl oz
85 gal
10,880 fl oz
86 gal
11,008 fl oz
87 gal
11,136 fl oz
88 gal
11,264 fl oz
89 gal
11,392 fl oz
90 gal
11,520 fl oz
91 gal
11,648 fl oz
92 gal
11,776 fl oz
93 gal
11,904 fl oz
94 gal
12,032 fl oz
95 gal
12,160 fl oz
96 gal
12,288 fl oz
97 gal
12,416 fl oz
98 gal
12,544 fl oz
99 gal
12,672 fl oz
100 gal
12,800 fl oz
Fluid ounces (US) to gallons (US)
Fluid ounces (US)
Gallons (US)
1 fl oz
0.01 gal
2 fl oz
0.02 gal
3 fl oz
0.02 gal
4 fl oz
0.03 gal
5 fl oz
0.04 gal
6 fl oz
0.05 gal
7 fl oz
0.05 gal
8 fl oz
0.06 gal
9 fl oz
0.07 gal
10 fl oz
0.08 gal
11 fl oz
0.09 gal
12 fl oz
0.09 gal
13 fl oz
0.1 gal
14 fl oz
0.11 gal
15 fl oz
0.12 gal
16 fl oz
0.12 gal
17 fl oz
0.13 gal
18 fl oz
0.14 gal
19 fl oz
0.15 gal
20 fl oz
0.16 gal
21 fl oz
0.16 gal
22 fl oz
0.17 gal
23 fl oz
0.18 gal
24 fl oz
0.19 gal
25 fl oz
0.2 gal
26 fl oz
0.2 gal
27 fl oz
0.21 gal
28 fl oz
0.22 gal
29 fl oz
0.23 gal
30 fl oz
0.23 gal
31 fl oz
0.24 gal
32 fl oz
0.25 gal
33 fl oz
0.26 gal
34 fl oz
0.27 gal
35 fl oz
0.27 gal
36 fl oz
0.28 gal
37 fl oz
0.29 gal
38 fl oz
0.3 gal
39 fl oz
0.3 gal
40 fl oz
0.31 gal
41 fl oz
0.32 gal
42 fl oz
0.33 gal
43 fl oz
0.34 gal
44 fl oz
0.34 gal
45 fl oz
0.35 gal
46 fl oz
0.36 gal
47 fl oz
0.37 gal
48 fl oz
0.38 gal
49 fl oz
0.38 gal
50 fl oz
0.39 gal
51 fl oz
0.4 gal
52 fl oz
0.41 gal
53 fl oz
0.41 gal
54 fl oz
0.42 gal
55 fl oz
0.43 gal
56 fl oz
0.44 gal
57 fl oz
0.45 gal
58 fl oz
0.45 gal
59 fl oz
0.46 gal
60 fl oz
0.47 gal
61 fl oz
0.48 gal
62 fl oz
0.48 gal
63 fl oz
0.49 gal
64 fl oz
0.5 gal
65 fl oz
0.51 gal
66 fl oz
0.52 gal
67 fl oz
0.52 gal
68 fl oz
0.53 gal
69 fl oz
0.54 gal
70 fl oz
0.55 gal
71 fl oz
0.55 gal
72 fl oz
0.56 gal
73 fl oz
0.57 gal
74 fl oz
0.58 gal
75 fl oz
0.59 gal
76 fl oz
0.59 gal
77 fl oz
0.6 gal
78 fl oz
0.61 gal
79 fl oz
0.62 gal
80 fl oz
0.62 gal
81 fl oz
0.63 gal
82 fl oz
0.64 gal
83 fl oz
0.65 gal
84 fl oz
0.66 gal
85 fl oz
0.66 gal
86 fl oz
0.67 gal
87 fl oz
0.68 gal
88 fl oz
0.69 gal
89 fl oz
0.7 gal
90 fl oz
0.7 gal
91 fl oz
0.71 gal
92 fl oz
0.72 gal
93 fl oz
0.73 gal
94 fl oz
0.73 gal
95 fl oz
0.74 gal
96 fl oz
0.75 gal
97 fl oz
0.76 gal
98 fl oz
0.77 gal
99 fl oz
0.77 gal
100 fl oz
0.78 gal
Common values
Gallons (US)
Fluid ounces (US)
Example
0.25 gal
32 fl oz
1 quart
0.5 gal
64 fl oz
Half gallon
1 gal
128 fl oz
1 gallon of milk
2 gal
256 fl oz
2 gallons
5 gal
640 fl oz
5-gallon bucket
10 gal
1,280 fl oz
10 gallons
12 gal
1,536 fl oz
Car fuel tank (approx.)
20 gal
2,560 fl oz
Aquarium size
50 gal
6,400 fl oz
50 gallons
55 gal
7,040 fl oz
Steel drum
100 gal
12,800 fl oz
100 gallons
About gallons (US) and fluid ounces (US)
Gallons (US) (gal). The US liquid gallon is exactly 231 cubic inches, about 3.785 liters. The UK imperial gallon is larger, about 4.546 liters.
Fluid ounces (US) (fl oz). The US fluid ounce is 1/128 of a US gallon, about 29.57 mL. The UK imperial fluid ounce is slightly smaller at about 28.41 mL.
Frequently asked questions
What is 1 US gallon in US fluid ounces?
One US gallon equals 128 US fluid ounces. These are US customary measures.
How do you convert US gallons to US fluid ounces?
Multiply the number of US gallons by 128. For example, 1 gal × 128 = 128 fl oz.
What is 12 US gallons in US fluid ounces?
12 gal is 1,536 fl oz (car fuel tank (approx.)).
How do I convert US fluid ounces back to US gallons?
Divide by 128, or press the ⇄ swap button above. For example, 1,536 fl oz ÷ 128 = 12 gal.
Are US and UK gallons the same?
No. The US liquid gallon is 3.785 liters, while the UK imperial gallon is 4.546 liters, about 20% larger. US quarts and pints are smaller than imperial ones for the same reason. This converter uses US liquid measures.
What is the difference between US and UK fluid ounces?
A US fluid ounce is 29.57 mL and a UK imperial fluid ounce is 28.41 mL. There are 16 US fl oz in a US pint but 20 imperial fl oz in a UK pint. This converter uses US fluid ounces.