Understanding cover

Cover is the number of days your household could eat from what it has stored. It is one number today and a line into the future.

Status. The arithmetic is built and runs every night and after any change to the pantry. The dashboard that shows it to you is on the site, under Pantry in the header. The front page shows a demonstration household, so the shape of it is there to look at before you sign in.

The number

Every member of your household has a daily energy requirement, worked out from their age, sex and how active they are, using published reference values. You can override it. Add the members together and you have what the household needs in a day.

Every item has an energy value from the catalogue, multiplied by how much of it you have and how much of it is edible. Add the items together and you have what the store holds.

Divide one by the other. That is cover today, in days.

What you keep in the freezer and the fridge counts too, unless you say otherwise: frozen and chilled food depends on power, so the household settings have a switch for each, and with a switch off those items are left out and the page says how many.

The number is always rounded down. Twenty-one and a half days is shown as 21, so the figure on screen is never more than the store holds.

The line

Items go out of date at different times, so the store shrinks as the months pass even if nothing is eaten. Cover at 30, 60, 90, 180 and 365 days is the same sum counting only the items still in date on that day. Drawn as a line it falls in steps, one step for each item that runs out. The line is the most useful thing on the page: it shows which items to use and replace first to keep the number where it is.

Cover at a future date is not the store minus what you would have eaten by then. It answers a plainer question: if nothing changes, what is left to eat on that day.

What the number is not

It is arithmetic over labelled values and published reference intakes. It is not dietary advice, and it does not know about allergies or preferences beyond what you have told it. Every check on the dashboard says what it looked at and what it can and cannot conclude.

Protein is worked out alongside energy and stored, but not led with, because whether to show it at all is still being decided.

The twelve checks

Twelve checks run on your store every night and after any change. Each has a name, a mechanism and a hedged outcome, and each result closes itself when the condition clears. They cover cover itself, rotation, the make-up of the store and the quality of the data behind it. Items with estimated dates, for instance, are counted, and a store built on estimates is said to be one.