Gallon.si
Your everyday guide to volume, measurement, and conversion
From cooking and gardening to fuel economy and home plumbing, Gallon.ai explains how volume measurements work - gallons, liters, quarts, and the math to convert between them - plus the history of where these units came from.
No card required · $9/mo Plus · $99/mo Premium
What you get
Everything Gallon.si gives you
🧮
Instant conversions
Gallons to liters, quarts to cups, cubic feet to gallons, explained with the math.
🌎
US vs Imperial
Clear answers on where gallon, pint, and quart sizes actually differ.
🛢️
Real-world sizing
Estimate fuel tanks, water barrels, and container volumes.
🔖
Saved conversion history
Sign in free and keep every conversation for later reference.
Go deeper
Volume and Measurement, Explained
Where common volume units come from and how they're used day to day.
Units and Origins
- US liquid gallon — 231 cubic inches, defined from old English wine-trade measures.
- Imperial gallon — The UK gallon, about 20 percent larger than the US gallon.
- Liter — The metric base unit of volume, defined as one cubic decimeter.
Everyday Uses
- Cooking conversions — Cups, quarts, and gallons in recipes, and how to scale them up or down.
- Fuel economy math — How miles per gallon and liters per 100 km are calculated and compared.
- Home water use — Rough gallons per day for showers, laundry, and irrigation.
Pricing
Simple plans that grow with you
Most popular
Plus
$9/mo
- ✓200 questions per day
- ✓Full saved conversation history
- ✓Step-by-step conversion breakdowns
Premium
$99/mo
- ✓Unlimited questions
- ✓Extended deep-dive answers
- ✓Everything in Plus