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Volume

FromUnit
gal
0100,000
To
Unit
45.42492

12 gal = 45424.92 mL = 45.42492 L = 189.2705 cup = 1536.000812 fl oz

Suggested Conversions

gal to L

Common Volume units

Tap a unit to set it as your "From" unit (use the rows above for From/To shortcuts).

Conversion tips

  • 1 L = 1,000 mL
  • 1 US gallon ≈ 3.785 L
  • 1 US cup = 240 mL
  • 1 US fluid ounce ≈ 29.57 mL
High Precision Engine

Quick Ratio

1 gal = 3.78541 L

Quick conversions

gal to L

Volume History

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Volume & Capacity Converter

Liquid and dry “cup” measures trip people up because US and metric labels don’t mean the same thing at every border. This page keeps the math in one place so you can scale recipes or compare container sizes without a notebook.

Why these units exist

The liter is tied to the meter cubed in SI, while US customary volume measures (gallon, cup) grew from older wine and grain gallons—hence the stubborn gap between “a gallon” and four liters.

Volume as length cubed

V_target = V_source × (m³ per source unit) / (m³ per target unit)

Each volume unit is defined as a cube of a linear measure or an agreed liquid volume. Because everything ultimately references the cubic meter, you only need consistent ratios—no offsets.

Four ideas worth memorizing

  • 11 mL = 1 cm³ exactly—swap mental models between liquids and small solids.
  • 2US cup ≠ metric cup: recipes need the label’s definition (usually 240 mL for US cup).
  • 3UK vs US gallon differ dramatically—never assume “gallon” on a European datasheet.
  • 4m³ × 1000 = L—move decimals for thousand-liter tanks instead of re-deriving.

Popular conversions on this tool

Jump straight in with common pairings—each link opens this same calculator with units and a value filled in, so you can bookmark or share it.

Where the standards come from

These are independent references—government labs, international measurement bodies, or university course materials—that explain the definitions behind the numbers. We don’t endorse third-party sites; we point to them for deeper reading.

How to Convert Volume

Short version: To convert US Gallons to Liters, multiply by 3.785.

  1. Select your starting volume unit.
  2. Input the amount.
  3. Select your target unit (e.g., Liters).
  4. The result reflects the specific volume definition selected.

Examples people look up

1 Gallon (US)3.785 Liters
1 Cup (US)240 Milliliters
1 Fluid Ounce29.57 Milliliters
1 Liter4.23 Cups

Popular searches we answer on-site

High-intent phrases people type into search engines—each link stays on OC - Online Calculator with a relevant calculator or example.

Frequently asked questions

Are US and UK gallons the same?

No, a UK (Imperial) gallon is about 20% larger than a US gallon.

How many cups in a quart?

There are 4 US cups in 1 US quart.

Why does my measuring cup disagree with a scale?

Volume tools vary by meniscus reading, temperature, and “cup” definition. For repeatability in baking, weigh ingredients when the author gives grams.

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Volume converter — liters, gallons, cups, ml | OC - Online Calculator