Volume Converter for Liters, Milliliters, Cups and Gallons Online
Convert metric, US customary, and Imperial volume units with instant results and clearly labeled measurement systems.
Convert Volume
Enter a volume, choose the starting unit, and select the unit you want.
How to Use the Volume Converter
The volume converter changes a value from one liquid or capacity unit to another. Enter the amount, choose the starting unit, then select the unit you need. The result updates instantly.
- Enter a volume. Use zero or any positive number.
- Select the starting unit. Choose metric, US customary, or Imperial units.
- Select the target unit. The converted volume appears immediately.
- Use Swap Units. Reverse the source and target without retyping the value.
- Check the equivalent values. The result panel also shows the same volume in common units.
Shortcut buttons make common volume conversions such as liters to milliliters, gallons to liters, and cups to milliliters faster to select.
How Volume Conversion Works
The calculator uses milliliters as its internal base. It first converts the entered value to milliliters, then converts that result into the selected target unit.
Volume in mL = Input Value × Source Unit Factor
Converted Volume = Volume in mL ÷ Target Unit Factor
This approach keeps the calculation consistent across metric, US customary, and Imperial units.
Volume Conversion Formula
Each unit has a fixed relationship to milliliters. Once the input is converted to the base unit, the calculator divides by the target unit’s milliliter factor.
Convert 2 liters to US gallons
2 L = 2,000 mL
2,000 ÷ 3,785.411784 = 0.528344 US gal
Metric Volume Units
Metric volume conversion is straightforward because liters and milliliters use a decimal relationship.
- 1 liter = 1,000 milliliters
- 1 milliliter = 0.001 liter
A liter is equal to one cubic decimeter, while one milliliter is equal to one cubic centimeter.
US Customary Volume Units
US customary liquid units use fixed relationships that differ from the Imperial system. The calculator labels them with “US” to prevent mix-ups.
- 3 US teaspoons = 1 US tablespoon
- 2 US tablespoons = 1 US fluid ounce
- 8 US fluid ounces = 1 US cup
- 2 US cups = 1 US pint
- 2 US pints = 1 US quart
- 4 US quarts = 1 US gallon
Imperial Volume Units
Imperial liquid measures are different from US customary measures even when they use the same unit names. This matters for gallons, pints, and fluid ounces.
- 1 Imperial fluid ounce = 28.4130625 mL
- 1 Imperial pint = 568.26125 mL
- 1 Imperial gallon = 4.54609 L
Common Volume Conversion Table
| Starting Unit | Equivalent Volume |
|---|---|
| 1 liter | 1,000 mL |
| 1 US teaspoon | 4.92892159375 mL |
| 1 US tablespoon | 14.78676478125 mL |
| 1 US fluid ounce | 29.5735295625 mL |
| 1 US cup | 236.5882365 mL |
| 1 US pint | 473.176473 mL |
| 1 US quart | 946.352946 mL |
| 1 US gallon | 3.785411784 L |
| 1 Imperial pint | 568.26125 mL |
| 1 Imperial gallon | 4.54609 L |
How to Convert Liters to Milliliters
Multiply liters by 1,000.
mL = L × 1,000
2.5 L to mL
2.5 × 1,000 = 2,500 mL
How to Convert Milliliters to Liters
Divide milliliters by 1,000.
L = mL ÷ 1,000
750 mL to liters
750 ÷ 1,000 = 0.75 L
How to Convert US Cups to Milliliters
One US cup equals 236.5882365 milliliters. Multiply the number of cups by that factor.
mL = US cups × 236.5882365
2 US cups to mL
2 × 236.5882365 = 473.176473 mL
How to Convert Milliliters to US Cups
Divide milliliters by 236.5882365.
US cups = mL ÷ 236.5882365
How to Convert US Gallons to Liters
One US gallon equals 3.785411784 liters.
L = US gallons × 3.785411784
5 US gallons to liters
5 × 3.785411784 = 18.92705892 L
How to Convert Liters to US Gallons
Divide liters by 3.785411784.
US gallons = L ÷ 3.785411784
How to Convert US Fluid Ounces to Milliliters
One US fluid ounce equals 29.5735295625 milliliters.
mL = US fl oz × 29.5735295625
8 US fl oz to mL
8 × 29.5735295625 = 236.5882365 mL
US vs Imperial Volume Units
US customary and Imperial systems share several unit names, but the sizes are not identical. This is one of the most important details in volume conversion.
A US gallon is about 3.785 liters. An Imperial gallon is 4.54609 liters. The difference is large enough to matter in fuel, recipes, product capacity, and other practical calculations.
Fluid Ounces vs Ounces
A fluid ounce measures volume. An ounce without the word “fluid” usually refers to mass or weight.
Common Volume Conversion Mistakes
- Mixing US and Imperial gallons. They are different sizes.
- Confusing fluid ounces with ounces. One measures volume and the other measures mass.
- Using a generic cup value. Cup sizes can vary by measurement system, so this tool labels the US cup clearly.
- Rounding too early. Keep full precision during the calculation and round the final result only.
- Assuming every unit scales by ten. That works within metric units, but not across US customary or Imperial units.
Volume Converter FAQs
What units does this volume converter support?
It supports milliliters, liters, US teaspoons, US tablespoons, US fluid ounces, US cups, US pints, US quarts, US gallons, Imperial fluid ounces, Imperial pints, and Imperial gallons.
How many milliliters are in one liter?
One liter contains 1,000 milliliters.
How many liters are in one US gallon?
One US gallon equals 3.785411784 liters.
How many liters are in one Imperial gallon?
One Imperial gallon equals 4.54609 liters.
How many milliliters are in one US cup?
One US cup equals 236.5882365 milliliters.
Is a fluid ounce the same as an ounce?
No. A fluid ounce is a volume unit, while an ounce is commonly used as a mass unit.
Are US and Imperial pints the same?
No. A US pint is 473.176473 mL, while an Imperial pint is 568.26125 mL.
Sources and Calculation Methodology
Conversion factors reviewed September 13, 2026.
The calculator uses milliliters as its internal base unit. Metric values use decimal relationships, while US customary and Imperial units use fixed conversion factors.
- BIPM: International System of Units
- NIST: SI Units and Conversion Factors
- NIST: US Customary Units and Metric Conversion Guidance
- UK Weights and Measures Standards
For other measurement types, use the Length Converter, Weight Converter, or Temperature Converter.