The internet loves to ask: “What’s 1/3 cup in mililiters?” Answer: 79 ml. That’s about three shots of espresso. Or half a can of soda. Or the volume of a small hummingbird’s soul.
If you have a baby bottle with markings, you can use that. Just don’t let the baby see you. They get jealous of flour.
Pro tip: Use a standard coffee mug. Most mugs hold 8 to 12 ounces (240–350 ml). Fill it roughly one-quarter to one-third full. It’s not scientific. It’s mug science.