Restock par calculator

What a par level is

A par level is the amount of something you keep on hand so you never run out between restocks. Hotels use it for linen and supplies, and it works just as well for one apartment. Below par, you buy. At or above par, you don't. It replaces the guesswork of standing in a cupboard deciding whether six rolls is enough.

This calculator sets par as what the stays until your next restock will use, plus one stay spare. The spare stay covers the guest who uses more than usual, a late delivery, or a turnover that comes sooner than planned.

The sum

Each item has a usage rate and a basis. Toilet roll is counted per guest per night, dishwasher tablets per night, kitchen roll per stay, and shampoo per guest per stay. The tool works out what one stay uses from your guests and stay length, then multiplies by the stays between restocks plus one, and rounds up to a whole unit.

For example, with 2 guests, 3-night stays, 8 turnovers a month and a monthly restock, one stay uses 2 times 3 times 0.5, so 3 rolls of toilet roll. The month has 8 stays, plus one spare makes 9, so par is 27 rolls. If you have 10 in the cupboard, you buy 17.

The usage rates are starting points

The rates in the table are starting points I picked to get you going, not measured averages. Your guests, your bottle sizes and your coffee machine are not anyone else's. Change any rate to match what you see, and the par levels update straight away.

The best way to find your own rates is to count. Write down what is in the cupboard before a turnover and after the next one, for three or four stays. Divide what was used by the guests and nights, and type that in. After a month you will have rates that fit your place.

Restocking more often

If you restock every week or every two weeks, par is smaller, because it only has to cover the stays until the next shop. The tool counts a month as four weeks, so a weekly restock covers a quarter of your monthly turnovers, plus the spare stay. Smaller par means less money sitting in a cupboard and less to store, at the cost of more trips.

Linen, towels and the essentials

Airbnb lists toilet paper, soap for hands and body, one towel per guest, one pillow per guest and linen for each guest bed as essential amenities (help 2343). It also says listings that have the essentials option selected but "don't actually provide the items" may be penalised.

That is why the tool adds linen and towel sets. It uses three sets for each bed and each guest: one in use, one in the wash and one spare. If you leave the beds box blank, it assumes one bed for every two guests, rounded up, so check that against your own beds.

Making it a habit

Print the list and keep it inside the supply cupboard door. Ask whoever does the turnover to write the count next to each item before they leave. When a count is at or below par, it goes on the shopping list. That one habit, done every turnover, is what stops the message from a guest at ten at night.

If you use a cleaner, this also gives them a clear rule instead of a judgement call. The par number is the line.

What this calculator leaves out

It doesn't know your prices, so it doesn't work out the cost per stay; the Restock + Par Level Tracker does that, with an order log. It doesn't cover long-life items such as light bulbs or batteries. Nothing you type here is stored or sent anywhere.