ml to oz, oz to grams, inches to cm:
the cosmetic packaging unit converter and size tables.

The converter

Four tabs: volume (ml against US and UK fl oz), weight with a formula-density preset so "how many grams is a 50 ml jar of lotion" gets a real answer instead of a water assumption, length for the drawing, and a quick picker that turns a standard bottle size into its ounce label, weight, typical dimensions and what it looks like in hand. Everything runs in your browser.

Millilitres to fluid ounces, 1–500 ml

Thirty capacities from the 1 ml ampoule to the 500 ml family shampoo. US fluid ounces are what a US label prints; the gram column assumes water at 1.00 g/ml, so apply the density note below before using it for an oil or a perfume.

Fluid ounces to millilitres: the ten sizes US labels use

Read this from the ounce side when a US retailer specifies the size. The "sold as" column is the metric bottle a partner factory actually has on the shelf: 1.7 oz is not a separate 50.3 ml tool, it is the 50 ml bottle with a US label.

Why 1.7 oz means 50 ml and 3.4 oz means 100 ml. The metric sizes came first. Fragrance and skincare houses design in millilitres, and the 100 ml ceiling comes from the carry-on liquids rule in the US, EU and UK, which limits each container to 100 ml / 3.4 oz. So 100 ml became the flagship perfume size and 50 ml its hero half. When those bottles are labelled for the US market the millilitres are divided by 29.5735 and rounded to one decimal: 50 ÷ 29.5735 = 1.69, printed as 1.7; 100 ÷ 29.5735 = 3.38, printed as 3.4. The reverse trap is real: a brief that says "2 oz" gets a 60 ml bottle, not a 50 ml, and "4 oz" gets 120 ml, not 100 ml — both are 20% larger and neither fits a 100 ml carton. Our perfume bottle supplier page and fragrance bottles specification carry the 30 / 50 / 100 ml component set.

Ounces to grams for creams, balms and powders

This is the other ounce. A jar is sold by net weight, so its label reads "2 oz / 56 g", and that ounce is the avoirdupois weight ounce of 28.3495 g, not the 29.5735 ml fluid ounce. The two differ by about 4% for water and more for anything lighter or denser — enough to fail a fill check. Use this table for anything in a cosmetic jar or a tube.

The density step. Converting a jar's millilitre capacity to a gram fill needs the formula's density. A 50 ml jar holds about 50 g of a lotion or cream at 0.95–1.05 g/ml, about 46 g of a facial oil at 0.91–0.93 g/ml, and about 43 g of an alcohol-based perfume at 0.85–0.87 g/ml. Whipped textures are lighter still; clay masks and sugar scrubs are heavier than water. The rule: specify the net weight in grams at your formula's density and let the fill line follow, or specify the fill line in millilitres and accept that the declared weight follows the density. Specifying neither is how a 50 ml jar ends up over-filled with a light cream. And a bottle's nominal size is not its brim-full volume — a "100 ml" bottle is a cavity of roughly 105–115 ml held to ±5% and filled to 100.

Inches to centimetres and millimetres for drawings and cartons

Partner-factory drawings are in millimetres: neck finish, height, diameter, wall thickness. US retailers, Amazon listing fields and many US carton suppliers work in inches. The conversion is exact (1 in = 25.4 mm), so the only errors are rounding errors, and those matter at the neck: a 20/410 neck is 20 mm across, and "0.79 in" rounded to "0.8 in" is 20.3 mm — the difference between a closure that seals and one that weeps. Keep millimetres as the master and treat inches as a display unit; the neck finish and closure standards reference lists thread sizes in millimetres.

Why cosmetic labels show both ml and fl oz

Two label conventions drive the dual figures — packaging context, not legal advice.

• United States — dual declaration. Under the Fair Packaging and Labeling Act framework, consumer-commodity labels state the net quantity in US customary units with the metric equivalent alongside, so a bottle reads "1.7 fl oz / 50 ml" and a jar reads "2 oz / 56 g". Liquids are declared by fluid volume, solids and semi-solids by weight; the rounding produces the familiar 1.7 / 3.4 figures. Confirm current requirements with a labelling professional.
• European Union and UK — the ℮ mark. Prefilled packs that follow the EU average-fill system may carry the "℮" (estimated) symbol next to the metric quantity, showing the fill conforms to the average-quantity rules; the declaration is metric. UK domestic labels are metric, with imperial allowed as a supplementary indication.
• What this means for the bottle. The fill must meet the declared quantity and still sit below the brim with headspace, which is why the drawing capacity is larger than the label figure. Check the artwork, the fill line and the drawing against the same millilitre or gram number before the print plate is made. The quality standards page covers the capacity tolerance and the fill check.

Four conversion mistakes that cost a production run

1. Fluid ounce on a jar, weight ounce on a bottle. The most common first-run labelling error. Bottles of liquid carry fl oz; jars and tubes of cream carry oz (net wt.) and grams.
2. Reading a UK spec as a US one. A "3.5 fl oz" imperial label and a "3.4 fl oz" US label are the same 100 ml bottle; a buyer who converts 3.5 US fl oz gets 103.5 ml and orders the wrong glass.
3. Ordering "2 oz" when the brand meant 50 ml. 2 US fl oz is 59 ml, so the factory supplies a 60 ml bottle, and the carton, the label and the carry-on story were all built around 50 ml.
4. Rounding inches on a neck or a carton. Keep millimetres as the master dimension; convert to inches for display only, and ask the partner factory for the drawing in both if a US supplier is making the insert or carton.

A 50 ml or 100 ml stock bottle carries the lowest minimum; an odd ounce size with no metric equivalent may need a private mould. The MOQ index lists the indicative minimums by format, and the glass bottles page carries the stock capacities.

Common questions

Vella is a Guangzhou-based beauty packaging solutions provider: a sourcing partner that routes briefs to vetted partner factories operating to ISO 22716 / GMP, and checks the millilitre, gram and inch figures on the drawing, the label and the fill specification against each other before a run is released.