Leak Calculator

How Much Is Leaving Your Business Right Now?

Three mechanisms quietly cost fine-wine merchants money: storage you pay for and never recharge, a duty table nobody remembers to update, and dispatches that leave without an invoice behind them. Type your own numbers in below and see a gross annual figure, broken out by mechanism, with every formula and every source shown next to the result. It answers one question: how much is leaving your business right now, on your own figures.

Start Calculating Read About the Three Leaks

Work Out Your Own Number

Every figure below is either something you typed, or a rate cited to its source — nothing is assumed on your behalf. Four things you already know, then four things only you can estimate.

Your numbers

Nothing is sent anywhere — this runs in your browser only

What you already know

For context only — not part of the total below.

The figure on your warehouse's own invoice, whatever it currently is.

However many times stock leaves bond in an average month.

Rough is fine. Shown for context below — not converted into a pound figure, because we don't know what an hour of your team's time is worth to you and won't guess.

Your own estimates — required, nothing here is assumed for you

Nobody publishes a rate for this — it depends entirely on how good your own reconciliation is. Give your own honest estimate; round down if in doubt.

Not sure? The UK duty bands effective 1 February 2026 run £30.62 per litre of pure alcohol for most still wine (8.5–22% ABV) plus 20% VAT on top — source: GOV.UK “Alcohol Duty rates”, the same table this platform's own duty preview uses. Work it out from a typical case, or use that preview.

Your own estimate of how often a case leaves and nobody raises the paperwork behind it. If you genuinely don't know, that's itself worth finding out — it's exactly what a leak audit checks.

Optional. Only fill this in if you already suspect your own table is out of date — we are not going to guess a number on your behalf. See the note beside this result below for why, and for a real, sourced precedent.

Leak 1 — Storage never recharged

Formula
Annual storage bill × the share you estimate goes unrecharged
Your numbers
Enter your monthly storage bill and your unrecharged-share estimate above.
Annual leak
—

This is the storage cost you are already paying the warehouse, before any margin you'd normally add when recharging it — a floor, not a ceiling.

Leak 2 — Duty rate-drift exposure

Formula
Annual duty & VAT value at withdrawal × the size of drift you suspect in your own table
Your numbers
Enter your withdrawals per month and average duty & VAT value above. The drift estimate is optional.
Annual exposure
not estimated

This is exposure, not a confirmed loss, and it runs in either direction: this platform's own history includes a real, corrected instance where a stale rate overstated duty on its own main product line by about 11% — not understated it. If you haven't entered a drift estimate above, this line is excluded from the total below rather than assumed at zero.

Leak 3 — Dispatches that never invoice

Formula
(Withdrawals per month × 12) × average duty & VAT per withdrawal × the share you estimate goes uninvoiced
Your numbers
Enter your withdrawals per month, average duty & VAT value, and uninvoiced-share estimate above.
Annual leak
—

The withdrawal invoice (duty & VAT) is raised automatically on every recorded dispatch by default; where that doesn't happen today, this is the duty & VAT cost absorbed instead of recharged.

Gross annual leak £0.00

Enter your numbers above to see a total. This is a gross figure built entirely from what you typed — nothing here is netted against the cost of using this or any other system, and it makes no claim about what using one would be worth to you.

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This Is Your Own Estimate. Here Is the Real Number.

Send us one month of your real warehouse storage bill and your holdings export, and we'll run this platform's own cost-vs-recovery reconciliation directly on your numbers — not an estimate typed into a form. For how the duty half of that number is actually worked out, see our wine trade duty calculation software page.

See What You’d Recover — Free