Use the declared unit
All three selected packages are described in millilitres: 250 ml, 200 ml and 75 ml. A cream can be sold by volume; the word cream does not make its number a mass. A different package marked 75 g would require a separate mass-based record, not automatic conversion.
Density is not assumed
The site has no verified product-specific density. It therefore cannot treat one millilitre as one gram or turn volume rates into mass rates. The calculator rejects mass-based requests for these selected volume records. The same restriction applies even if a shopper thinks the products look equally thick.
A concrete example
Two of the selected Weleda 75 ml packages give 150 ml of declared packaged volume. They do not establish 150 g of product. A separate 150 g balm would not share this denominator without further evidence. Compare the selected ticket per declared 100 ml, then keep formulation and purpose visible.
A practical comparison
If a seller offers a 100 g product against a 100 ml reference, display the two denominators rather than choosing a presumed density. Even a correct arithmetic conversion from litres to millilitres cannot bridge mass and volume. The stock tool accepts only the selected declared unit and does not infer remaining contents by looking at a photograph.
What to check on arrival
Read whether the actual supplied pack says ml or g and whether it is a single product or a set. If the unit differs from the web record, preserve that difference and stop the cross-unit comparison. The site has not weighed or measured received contents.
Sources & scope
Checked November 5, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or retailer instructions. Current received labels and independent paediatric/clinical/material/content/commerce review remain pending.