Calculator
List each price the product actually carried, with the date each price took effect (sale prices included — the rule looks at prices you really applied, not only "regular" prices).
What the rule says, in plain terms
Since 28 May 2022, when a seller in the EU announces a price reduction, Art. 6a of Directive 98/6/EC (added by the “Omnibus” Directive (EU) 2019/2161) requires the announcement to state the prior price — defined as the lowest price the seller applied during a period of at least 30 days before the reduction.
Practically: the struck-through “was” price next to your sale price may not simply be the last regular price. If the product was on a promotion at any point in the previous 30 days, that promotional price is usually the one you must show — and your discount percentage should be computed against it (the Court of Justice confirmed this reading for percentage claims in C-330/23, Aldi Süd, 2024).
How the calculator works
- Each price you enter is treated as in force from its date until your next change.
- The tool looks at the 30 days immediately before your reduction date.
- It returns the lowest price that was in force at any point in that window — including a price set earlier that was still running when the window opened.
If your entered history doesn't cover the whole window (say the product launched two weeks ago), the tool says so instead of guessing: several member states treat new products differently, and an honest gap is better than a wrong number.
Member states apply it differently
| Market | What differs from the EU baseline |
|---|---|
| Germany (PAngV §11) | During a progressive promo, the reference may stay anchored to the pre-promo low rather than rolling with each step. |
| Poland | The 30-day reference is prominent in enforcement practice (UOKiK); progressive discounts get scrutiny against the pre-promo low. |
| Denmark / Finland / Netherlands | Guidance addresses gradually increasing discounts and how long a reference stays valid mid-campaign. |
| Spain / Italy | National transpositions carry their own wording and exemptions (e.g. perishables). |
This calculator computes the EU baseline. If you sell into a specific market, check its transposition — or use an app that applies the per-country rule for you.
Our free Shopify app records your price history automatically via webhooks, computes the prior 30-day lowest per variant under the member-state rule you pick, shows it on the product page through a theme block, and exports the raw history as audit evidence. See the PriceProof suite — the EU Omnibus app returns to the App Store after its current review cycle.
FAQ
Which price counts as the “prior price” for a sale?
The lowest price you actually applied in the (at least) 30 days before announcing the reduction — including promotional prices in that window, not just your regular price.
Does the rule apply to my Shopify store?
The rule applies to sellers announcing price reductions to consumers in the EU, whatever platform they sell on. On Shopify, a struck-through compare-at price is normally such an announcement.
What about discounts shown as a percentage?
In C-330/23 the CJEU held that a percentage reduction must be based on the prior 30-day lowest price. A “-30%” computed from a higher old price overstates the reduction if the 30-day low was lower.
What if my product is brand new?
With less than 30 days of price history the baseline reference can't be formed yet; member states differ on how to handle newly launched products. The calculator will flag this rather than output a number.
Do sales in my email or ads count?
The duty attaches to announcements of price reductions — which can include ads and newsletters, not only the product page. This tool (and our app) covers the on-storefront figure; announcements elsewhere are your responsibility.
Is my data uploaded?
No. The calculation runs entirely in your browser; this page has no analytics, no accounts and no server calls.