How Many Hydro Flasks Equal a Gallon or Liter?

Hydro Flask bottles come in many different shapes and sizes and are usually measured in US ounces.

So how many Hydro Flasks bottles does it take to make a gallon or to make a liter?

It takes 4 bottles of 32 oz Hydro Flasks to make a Gallon, 6.4 bottles of the 20 oz and 5.3 bottles of the 24 oz size. The 64 oz Hydro Flask is half a gallon and the 128 oz Hydro Flask is a full gallon. The 32 oz is closest to 1 Liter at 946 mL.

Below is a table showing the different sized Hydro Flasks as well as their volume in mL and how many of each bottle you need to make a full gallon or liter:

Size Hydro Flask	Volume in mL	Bottles Required To Make a Gallon	Bottles Required To Make a Liter
12 oz	355 mL	10.7	2.82
16 oz	473 mL	8	2.11
18 oz	532 mL	7.1	1.88
20 oz	592 mL	6.4	1.69
21 oz	621 mL	6.1	1.61
24 oz	710 mL	5.3	1.41
25 oz	749 mL	5.1	1.34
32 oz	946 mL	4	1.06
40 oz	1,182 mL	3.2	0.85
64 oz	1,892 mL	2	0.53
128 oz	3,785 mL	1	0.26