How to calculate consumption and plan the supply of hygiene materials

Many purchase orders simply repeat the previous month or are decided on the spot by looking at the shelf. The result is familiar: a surplus of one item, a shortage of another and emergency purchases, which tend to cost more.

Calculating consumption does not require complex tools. It requires knowing how many people use the spaces, on how many days and how much each person consumes on average.

The monthly consumption of each item follows a straightforward calculation:

• Monthly consumption = consumption per user per day × number of users × days of use in the month.
• Add a safety margin to the result to cover visitors, events and variations.

Consumption per user per day is the trickiest figure. It varies with the product, the dispenser, the user profile and how much time people spend on site. Ideally, measure it in the building itself: track how much material goes out over a few weeks and divide by the number of users and days.

The same reasoning applies to paper towels, soap and trash bags, each in its own unit (sheets, milliliters or units). In locations with fluctuating foot traffic, such as lobbies and retail areas, include an estimate of visitors per day.

Hypothetical example, just to illustrate the method: an office has 200 people and operates 22 days a month. After measuring for a few weeks, the team arrived at an average consumption of 0.1 roll of toilet paper per person per day.

• Monthly consumption: 0.1 × 200 × 22 = 440 rolls.
• With a 10% safety margin: 440 + 44 = 484 rolls.

The numbers are only there to show the calculation. Each building will have its own consumption, and that is the figure that should go into the calculation.

Knowing monthly consumption solves half the problem. The other half is deciding when to order. For this, use the concept of minimum stock:

• Minimum stock = average daily consumption × replenishment lead time (in days) + safety stock.

Replenishment lead time is the time between placing the order and the material arriving on site. Safety stock is a reserve for delays and unexpected spikes in consumption.

1. Continuing the same hypothetical example

   Average daily consumption is 440 ÷ 22 = 20 rolls. If delivery takes 5 business days and the company decides to keep 3 days in reserve, the minimum stock is 20 × 5 + 20 × 3 = 160 rolls. When inventory reaches that number, it is time to place the order.

Having inventory in the stockroom does not mean having paper in the restroom at the right time. Restocking the points of use needs its own routine:

• Restocking routes with set times, covering the busiest restrooms before peak use.
• A small forward stock on each floor or building wing, to avoid long trips.
• Dispensers with level windows, or level checks recorded on the checklist.
• Records of stockroom withdrawals by area, to identify unusual consumption.

Consumption changes over time. New hires, hybrid work, events and even a switch to a different type of paper change the numbers. Review the parameters periodically, comparing forecast consumption with actual consumption.

Large differences deserve investigation. Consumption well above the forecast may indicate waste, improper removal or an unsuitable dispenser. Consumption well below it may mean that supplies are running out at the point of use and no one is recording it. In both cases, the number is the start of the conversation, not the end.