# Volume Converter

> Convert volume units: liter↔gallon, mL↔fl oz.

## What is the Volume Converter?

The Volume Converter converts between different volume measurement units. It provides two conversion tabs: liters↔gallons (US) and milliliters↔fluid ounces (US).

The liter (L) is the standard metric unit of volume used worldwide, defined as exactly 1 cubic decimeter (1,000 cm³). The milliliter (mL) equals 1/1,000 of a liter. These units are used for beverages, cooking, fuel, medicine, and scientific measurements in most countries.

The gallon and fluid ounce are part of the US customary system. The US gallon (3.785 L) differs from the Imperial gallon used in the UK (4.546 L). This converter uses the US gallon, which is the more commonly encountered version. One US gallon = 128 fluid ounces = 4 quarts = 8 pints.

Volume conversions are essential when following international recipes, understanding fuel efficiency (MPG vs L/100km), comparing beverage sizes across countries, and for medical dosage calculations. A common source of confusion is that a US gallon is about 20% smaller than an Imperial gallon, which affects fuel economy comparisons between US and UK vehicles.

## How to Use

1. Select a conversion tab.
• L ↔ gallon: Convert between liters and US gallons. Used for fuel, large liquid volumes.
• mL ↔ fl oz: Convert between milliliters and US fluid ounces. Common for beverages, cooking, medicine.

2. Enter a value in either field.
Type a number and the conversion appears instantly.

Common Examples:
• Water bottle: 500 mL = 16.91 fl oz
• Soda can: 355 mL = 12 fl oz
• Wine bottle: 750 mL = 25.36 fl oz
• Car fuel tank: 60 L = 15.85 gallons
• Milk gallon: 1 gallon = 3.785 L
• Medicine dose: 5 mL = 0.169 fl oz (1 teaspoon)

Note: This converter uses US customary units. UK Imperial fluid ounces and gallons are slightly different (1 UK fl oz = 28.41 mL vs 1 US fl oz = 29.57 mL). When following British recipes or converting UK fuel economy figures, be aware of this distinction.

## Conversion Formulas

■ Liters ↔ US Gallons
1 US gallon = 3.785411784 L (exact)
1 L = 0.264172 US gallons

Formula: gallons = L ÷ 3.785411784
Formula: L = gallons × 3.785411784

Example: 50 L = 50 ÷ 3.7854 = 13.21 gallons
Example: 10 gallons = 10 × 3.7854 = 37.85 L

■ Milliliters ↔ US Fluid Ounces
1 US fl oz = 29.5735296 mL (exact)
1 mL = 0.033814 US fl oz

Formula: fl oz = mL ÷ 29.5735296
Formula: mL = fl oz × 29.5735296

Example: 250 mL = 250 ÷ 29.574 = 8.45 fl oz
Example: 16 fl oz = 16 × 29.574 = 473.18 mL

■ US vs Imperial
1 US gallon = 3.785 L | 1 UK gallon = 4.546 L
1 US fl oz = 29.574 mL | 1 UK fl oz = 28.413 mL

■ Volume Unit Hierarchy
1 US gallon = 4 quarts = 8 pints = 16 cups = 128 fl oz
1 quart = 946.35 mL | 1 pint = 473.18 mL | 1 cup = 236.59 mL

■ Quick Reference
1 teaspoon = 5 mL | 1 tablespoon = 15 mL = 3 tsp
1 cup = 236.59 mL | 1 pint = 473 mL | 1 quart = 946 mL
1 L = 4.227 cups | 1 L = 2.113 pints | 1 L = 1.057 quarts

## Helpful Tips

■ Quick Mental Conversions
• Liters to gallons: Divide by 4 (rough). 20 L ≈ 5 gallons (actual: 5.28)
• Gallons to liters: Multiply by 4. 5 gallons ≈ 20 L (actual: 18.93)
• mL to fl oz: Divide by 30. 300 mL ≈ 10 fl oz (actual: 10.14)
• fl oz to mL: Multiply by 30. 8 fl oz ≈ 240 mL (actual: 236.6)

■ Beverage Size Comparisons
Korean/metric sizes vs US sizes:
• Korean soju bottle: 360 mL = 12.2 fl oz
• Korean beer can: 500 mL = 16.9 fl oz
• US soda can: 12 fl oz = 355 mL
• US large drink: 32 fl oz = 946 mL
• Starbucks Grande: 473 mL = 16 fl oz
• Starbucks Venti: 591 mL = 20 fl oz

■ Fuel Economy Conversion
• US uses MPG (miles per gallon): higher = better
• Korea/EU uses L/100km: lower = better
• Conversion: L/100km = 235.21 ÷ MPG
• 30 MPG = 7.84 L/100km | 40 MPG = 5.88 L/100km

■ Cooking Measurements
• 1 cup (US) = 236.6 mL ≈ 240 mL in many recipes
• Korean recipe '1컵' = 200 mL (different from US cup!)
• Japanese recipe '1カップ' = 200 mL
• Australian cup = 250 mL

■ Common Mistakes
• US gallon ≠ UK gallon (3.785 L vs 4.546 L)
• When comparing US and UK fuel economy, account for gallon difference
• Don't confuse fluid ounces (volume) with ounces (weight)

## Frequently Asked Questions

### Q. What's the difference between a US gallon and an Imperial (UK) gallon?

A US gallon equals 3.785 liters while an Imperial (UK) gallon equals 4.546 liters — about 20% larger. This means a car getting 30 MPG in the US (using US gallons) would show about 36 MPG using UK gallons. The difference dates back to 1824 when Britain redefined its gallon based on the volume of 10 pounds of water, while the US kept the older wine gallon measure. This converter uses US gallons, which are more commonly encountered internationally. Always check which gallon system is being referenced.

### Q. How do I convert cooking measurements between metric and US?

Key cooking conversions: 1 US cup = 236.6 mL (often rounded to 240 mL), 1 tablespoon = 15 mL, 1 teaspoon = 5 mL. For precise baking, use weight (grams) rather than volume when possible, as cup measurements vary by ingredient density. Note that Korean recipes typically use 200 mL for '1 cup' while US recipes use about 237 mL — this 15% difference can significantly affect baking results. When following international recipes, always verify which measurement system is being used.

### Q. Why are there different systems for measuring volume?

Volume measurement systems evolved independently in different regions. The metric system (liters) was created during the French Revolution (1795) to standardize measurements using base-10. The US customary system derives from English units that were in use before American independence, based on the wine gallon (231 cubic inches). The UK later reformed its system in 1824 (Imperial units), creating a different gallon. Today, most countries use the metric system, but the US retains its customary units for everyday use, while using metric for scientific work.

### Q. How do I calculate fuel economy between L/100km and MPG?

To convert from L/100km to US MPG: divide 235.21 by the L/100km value. For example, 8 L/100km = 235.21 ÷ 8 = 29.4 MPG. To convert from US MPG to L/100km: divide 235.21 by the MPG value. For example, 35 MPG = 235.21 ÷ 35 = 6.72 L/100km. Note: for UK MPG, use 282.48 instead of 235.21 (because UK gallons are larger). Korean fuel economy is measured in km/L, which can be converted to L/100km by dividing 100 by the km/L value.

### Q. How much water should I drink per day in different units?

The commonly cited recommendation is about 2 liters (8 cups) of water per day, though actual needs vary by body size, activity level, and climate. In different units: 2 L = 0.528 US gallons = 67.6 US fl oz = about 8.5 US cups. The '8 glasses a day' rule assumes 8-ounce glasses (237 mL each), totaling 1.89 L. More recent guidelines suggest 3.7 L (125 fl oz) for men and 2.7 L (91 fl oz) for women from all sources including food. About 20% of daily water intake typically comes from food.