Bar stock, measured · v2 · 2026
Put the bottle down.
Read the number.
Swift Inventory weighs every open bottle on a Bluetooth scale and turns grams into millilitres — with the uncertainty shown. No tenths, no eyeballing, no pouring into a jug and back.
One hundred and thirty years
How a bar has counted its bottles.
From the stock book and the gas lamp to the measuring jug and the clipboard — every method was a guess wearing a uniform. Here is the short history, and where it ends.
Rendered live in your browser as a drawn sequence — no video file. A filmed version drops into the same frame when it's ready.
Scan · weigh · know
Three steps. One number you can defend.
A count line is a measurement with its inputs attached — raw grams, the empty weight, the pourer, the density used — so it can be recomputed later when the catalogue learns more.
Scan the barcode
The EAN resolves against Red Swift Master — the shared product registry — and brings back what the maths needs.
Put it on the scale
The driver owns the zero, watches the stream, and locks the reading when six consecutive samples agree within 3 g. No button to press.
Read millilitres, with ±
Grams become millilitres through the product's density. The line is appended to the venue's ledger as an event — corrections are new events, never edits.
remaining_ml = (gross_g − empty_g − pourer_g) / ρ
ρ = f(ABV) ethanol–water table · ±0.005 for spirits
σ_ml = √(σ_scale² + σ_empty² + (ml·σ_ρ)²) / ρ
700 ml · 40 % ABV liquid 663.6 g · σ_scale ≈ 1 g · σ_empty ≈ 4 g
→ 412 ml ± 4 shown as is — never false precision
- Stability is decided in software, not by the scale: σ of the last six samples under 3 g. Cheap load cells drift about 3 g in three minutes; the driver re-zeroes against its own reference, never the scale's.
- Placement matters more than electronics. Off-centre loading on a single-point cell shifts a reading by up to 10 g, so the app asks for the bottle in the middle of the platter.
- Liqueurs and syrups get a wider ± until enough measured pairs converge their category's density. The number tells you how much to trust it.
Plugs into the bar you already run
The count feeds ordering, sales and the books.
Swift Inventory is the measuring instrument in a family of tools built by the same studio. The stock level lands where it's useful.
One ledger per venue. Whichever system holds your stock ledger stays the ledger; Swift Inventory writes count events into it and never keeps a second copy of the truth.
2026 pilot
Count a bar with us before it ships.
We're taking a small number of venues through the pilot — a scale, the tablet app, and a weekly call with the people building it.