Price Per Litre Calculator
Use this unit price calculator to quickly find cost per litre, cost per 100 ml, and total volume in litres.
Why a price per litre calculator matters
A lower shelf price does not always mean better value. Packaging sizes, promotional bundles, and mixed units (like mL vs L) can make comparison difficult. This price per litre calculator converts everything into one clear number so you can make faster, smarter buying decisions.
Whether you are comparing milk, juice, cooking oil, paint, fuel, detergent, or bottled water, the same unit-price logic applies: divide the total price by total litres.
The formula
Basic cost per litre equation
Price per litre = Total price ÷ Total volume in litres
If your volume is in millilitres, convert first:
- 1,000 mL = 1 L
- 100 cL = 1 L
- 1 US gallon = 3.78541 L
- 1 UK gallon = 4.54609 L
How to use this calculator
- Enter the total amount you pay.
- Select a currency symbol.
- Enter the volume of one container.
- Choose the unit (mL, L, cL, US gallon, or UK gallon).
- Add the number of containers in the pack.
- Click Calculate to see cost per litre and related values.
Example comparisons
Example 1: Juice bottles
Bottle A costs $2.40 for 750 mL. Bottle B costs $3.00 for 1 litre. Bottle A price per litre is $3.20/L, while Bottle B is $3.00/L. Even though Bottle B has a higher sticker price, it is better value per litre.
Example 2: Multi-pack detergent
A 3-pack of 1.5 L detergent bottles costs €18. The total volume is 4.5 L. Unit price = €18 ÷ 4.5 = €4.00 per litre.
Example 3: Fuel-style unit conversion
If pricing is given for gallons, convert to litres first so comparisons remain accurate across regions. This helps when comparing travel costs, machinery fuel estimates, or imported pricing data.
Common mistakes to avoid
- Ignoring unit differences: mL and L must be normalized before comparison.
- Forgetting pack quantity: always include the number of containers.
- Using discounted sticker text only: check final payable price including offers or taxes when relevant.
- Rounding too early: keep more decimals until the final result.
When to use cost per 100 mL instead
For premium products like skincare, coffee syrups, and specialty oils, small sizes are common. In those cases, cost per 100 mL can be easier to understand than cost per litre. This calculator also shows that value so you can compare both ways.
Quick buying strategy
- Compare at least two brands using the same unit.
- Check storage life before buying larger volumes.
- Track your favorite products and their typical unit price.
- Use alerts: buy in bulk only when unit cost is genuinely lower.
Final thoughts
Price transparency builds better habits. A simple cost per litre check can save money consistently over time, especially for frequently purchased household items. Bookmark this page and use the calculator whenever you shop.