Price Per 100 Ml Calculator
A price per 100 ml calculator settles the aisle debate in seconds: enter what you pay and how many milliliters you get, and it tells you the true cost per 100 ml. Compare two products head to head, with multipack support, and one honest number decides which bottle is really cheaper.
Product A
Product B (optional)
Use the net content on the label, not the bottle size. Convert liters and fluid ounces to ml first (table below).
Quick Answer
Price per 100 ml = (price ÷ total volume in ml) × 100. A $4.50 shampoo with 250 ml costs $1.80 per 100 ml; a $7.50 bottle with 500 ml costs $1.50 per 100 ml. The second bottle costs more at the register but less per 100 ml: Product B wins, 16.7% cheaper, saving $3.00 per liter. Multiply any result by 10 for the per-liter price.
How to use this calculator
Enter Product A's price, pack count, and volume per unit in milliliters, then press Calculate. The fields come pre-filled with the shampoo comparison from the Quick Answer so you can press Calculate immediately to see the format. Add Product B to compare two products head to head; leave B blank to price a single product. The tool shows each product's cost per 100 ml and per liter, then names the winner with the percentage cheaper and the saving per liter. Results stay hidden until you press Calculate.
Worked comparison: two shampoos
Two bottles, same brand family, different sizes. Shampoo A: $4.50 for 250 ml = (4.50 ÷ 250) × 100 = $1.80 per 100 ml. Shampoo B: $7.50 for 500 ml = (7.50 ÷ 500) × 100 = $1.50 per 100 ml. B costs more at the register but less per 100 ml: Product B wins, 16.7% cheaper, saving $3.00 per liter. That gap adds up fast on products you rebuy. Enter 4.50/250 and 7.50/500 to reproduce this exactly.
The trap: your bottle is probably not labeled in ml
The calculator takes milliliters only, so convert before typing. US labels love fluid ounces and liters, and typing those numbers in raw gives nonsense:
| Your label says | Multiply by | Example |
|---|---|---|
| Liters (L) | 1,000 | 0.5 L = 500 ml |
| US fluid ounces (fl oz) | 29.5735 | 16 fl oz = 473.18 ml |
| US gallons (gal) | 3,785.41 | 1 gal = 3,785.41 ml |
Example: a $15 lotion in a 16 fl oz bottle is 473.18 ml, so (15 ÷ 473.18) × 100 = $3.17 per 100 ml. Typing 16 into the volume field would give a nonsense $93.75. Always convert first.
Net volume, not bottle size
Use the net content printed on the label: the actual liquid inside, not the size of the bottle. Two bottles can look identical on the shelf while one holds 200 ml and the other 180 ml; that quiet shrink is exactly what per-100-ml math exposes. The same goes for pump bottles that never fully empty: if the last 10 ml stays trapped, your effective price is higher than the label suggests.
How multipacks work
Enter the pack count and the volume per unit; the tool multiplies them for the total volume before dividing. A 6-pack of 330 ml cans at $12 is 1,980 ml total: (12 ÷ 1,980) × 100 = $0.61 per 100 ml, shown as "Product A (6 × 330 ml)" in the results. One honest limitation to know: pack counts are whole packs only, so a fractional entry like 2.5 is rounded down to 2. If you are comparing a sale price against the regular price, enter the sale price as Product A and the regular price as Product B; the verdict shows the real saving. For the discount math itself, our discount percent calculator breaks down any markdown.
Why 100 ml became the standard
Per-100-ml pricing is consumer-protection law in much of the world. In the UK, the Price Marking Order 2004 requires traders to show a unit price alongside the selling price so shoppers can compare like with like, implementing the EU's price-indication directive. That is why European shelves show "per 100 ml" or "per 100 g" under the big price. Online, Google's Merchant Center uses 100 ml as a standard unit-pricing base measure for product listings. This calculator gives you the same comparison power for online carts and unlabeled imports. Prefer per liter? Multiply the result by 10.
What competing calculators miss
Generic unit-price calculators do one product, no multipacks, no milliliter conversion table, and no verdict. YesCalculator's cost-per-100ml page walks through the formula with two examples but prices one product at a time. AreaCalculators and SavvyCalculator take a single price and volume with solved examples and stop there. Calculator Ultra shows the formula and one static lotion example. BraveCalculator's version compares nothing: one bottle in, one number out, thin FAQs.
- Head-to-head verdict: enter two products and the tool names the winner, with the percentage cheaper and the saving per liter.
- Multipack support: pack count × volume per unit, with the total volume shown in the working.
- Conversion table on the page: liters, US fluid ounces, and gallons to ml, so labels convert before typing.
- Legal context: why shelves show unit prices, and why the same math protects you online.
Shelf labels show unit prices but only within one store; this page compares any two products from anywhere. For solids sold by weight rather than volume, our price per 100 g calculator runs the same comparison in grams, and the cost per item calculator handles count-based goods like pods and wipes.
Frequently asked questions
It is the standard unit-price base on European shelves under the EU price-indication rules, and a convenient size for bottles. Multiply any result by 10 for the per-liter price.
Multiply US fluid ounces by 29.5735 to get milliliters: 16 fl oz = 473.18 ml. A $15 lotion in a 16 fl oz bottle works out to $3.17 per 100 ml.
Net volume from the label: the actual liquid inside, not the bottle's apparent size. Shrinkflation hides in exactly this gap.
Usually, but not always. Sales, multipacks, and shrinkflation break the rule, so always divide instead of assuming.
Yes, anything sold by volume. For solids sold by weight, use a price-per-100g comparison instead.
Consumer-protection law in much of the world requires unit pricing so shoppers can compare like with like. In the UK it is the Price Marking Order 2004, implementing the EU price-indication directive.
Yes. Enter the sale price as Product A and the regular price as Product B; the verdict shows the real saving per 100 ml and per liter.
Enter the pack count and the volume per unit; the tool multiplies them for the total volume before dividing. Whole packs only: a fractional pack count is rounded down.
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References
- UK Government. The Price Marking Order 2004: requires traders to indicate the selling price and, where required, the unit price of products. Accessed October 23, 2026.
- EUR-Lex. Directive 98/6/EC on consumer protection in the indication of the prices of products offered to consumers: the EU price-indication directive behind per-100-ml shelf pricing. Accessed October 23, 2026.
- Google Merchant Center Help. Unit pricing measure [unit_pricing_measure]: documents 100 ml as a standard unit-pricing base measure for product listings. Accessed October 23, 2026.
- National Institute of Standards and Technology. Guide for the Use of the International System of Units (SP 811): conversion factors including 1 US fluid ounce = 29.5735 ml and 1 US gallon = 3,785.41 ml. Accessed October 23, 2026.
- Bureau International des Poids et Mesures (BIPM). The International System of Units (SI Brochure): defines the litre as 1,000 millilitres. Accessed October 23, 2026.