Water & bottle guides
Start with the question you have. Volume conversions tell you how much a container holds; daily intake references answer a different question.
How many bottles is a gallon?
Convert US or Imperial gallons to your bottle size, including the remainder.
Water bottle sizes
Compare ml, liters and US fluid ounces, then choose a capacity that fits your refill routine.
2 liters in water bottles
A worked example and table for common capacities.
How much water should I drink?
Understand published adult references and what counts as total water.
Exercise and heat
Why a general reference does not calculate your exercise needs.
Water and weight loss
What the evidence can and cannot tell you.
Quick answers
Is 2 liters four bottles?
Yes, if each bottle holds 500 ml. Different bottle capacities give different counts. See the conversion table.
Is a US gallon the same as an Imperial gallon?
No. A US gallon is about 3.785 liters; an Imperial gallon is about 4.546 liters. Choose the system in the gallon converter.
Does a bottle count tell me how much to drink?
A bottle count expresses volume. A chosen volume or a population reference is not a personalized drinking prescription. Read the method and limits.