How Much PPE Should You Order? A Formula for Headcount, Shifts, and Reorder Points
This guide covers ordering for two commonly replenished PPE items: N95 masks and nitrile gloves. If you manage other protective gear too, the same math applies, but the worked numbers below are specific to masks and gloves.
Most articles on PPE inventory management are written by software companies trying to sell you a tracking platform. If you are managing PPE across a dozen sites, that may be worth it. If you just want to know how many boxes to order this month, you do not need software; you need a formula you can run in a spreadsheet in ten minutes. That is what this guide gives you.
- Daily Usage
- Reorder Point
- Safety Stock
- Order Quantity
- Build a Calculator
- Overall Stock Levels
- Common Mistakes
- FAQs
How to Calculate Daily PPE Usage
The technically accurate version of this formula accounts for the fact that different shifts often run with different staffing levels:
Daily PPE usage = the sum, across every shift, of active users on that shift x units used per person on that shift.
- Count active users per shift: Not your total headcount, just the people who actually put on a mask or gloves during that specific shift.
- Estimate units used per person, per shift: This depends on the role and the workplace conditions, so use your organization's own observed usage rather than a generic assumption. For N95 respirators specifically, replacement frequency should follow the manufacturer's instructions, fit, workplace contamination levels, and your organization's respiratory protection procedures, not job type alone.
- Repeat per shift and add the totals: A facility running three shifts does not automatically use three times the PPE of a single-shift operation. The real difference depends on how many people work each shift and how much each of them uses.
A worked example: a 40-person warehouse crew, running one 8-hour shift, with each worker using one mask per shift based on their own observed usage, works out to 40 masks a day.
For a Monday through Friday operation, that is 40 masks per operating day, or about 880 masks over a 22 workday month. If the same operation ran seven days a week, the monthly figure would be closer to 1,200. Use whichever day count actually matches how your facility operates, since the two figures are meaningfully different and mixing them leads to an inaccurate order.
Nitrile glove usage tends to run higher per person in roles involving frequent changes, so calculate it separately from mask usage using the same method. If you are also reviewing certification before placing a large order, our guide to buying N95 masks and PPE in bulk covers how to verify NIOSH approval before you commit to a bulk purchase.
The Reorder Point Formula
Once you know your daily usage, the next question is when to reorder, not just how much you use. This is a standard concept in inventory management, and it applies to PPE the same way it applies to any supply you use continuously.
Reorder point = (average daily usage x lead time in days) + safety stock
Worked example, using the 40 masks per operating day figure above and a supplier lead time of 2 business days:
- Average daily usage: 40 masks
- Lead time: 2 business days
- Lead time demand: 40 x 2 = 80 masks
- Safety stock, at 2 days of usage (explained below): 40 x 2 = 80 masks
- Reorder point: 80 + 80 = 160 masks
In plain terms, once this warehouse's mask stock drops to 160 units, it is time to place the next order, not when the shelf is empty.
Safety Stock for PPE: One Consistent Method
The simplest defensible way to size safety stock, without complex demand variability modeling, is to pick some days of average usage and hold that as your buffer. There is no universal PPE safety stock percentage or day count that fits every operation. The example above uses 2 days, which is a planning assumption for this specific worked case, not a fixed rule.
For the 40 masks per day example, 2 days of safety stock is 40 x 2, or 80 masks. A business with a less reliable supplier, more variable staffing, or higher consequences from running out might choose 4 or 5 days instead. A business with a very reliable, fast supplier might choose fewer. Pick some days that reflect your actual risk tolerance and supplier reliability, then stay consistent with it.
A few things that make it worth erring toward more days rather than fewer:
- Sizing and fit issues: Not every mask fits every face on the first try, and gloves come in a range of sizes that do not always match your headcount evenly.
- Damage and defects: Torn gloves, snapped straps, and masks that do not pass a seal check happen at a low but steady rate.
- Absenteeism and turnover: New hires who have not been added to your usage tracking yet, or temporary staff brought on for a busy stretch, add real demand your spreadsheet has not caught up to.
- Seasonal spikes: Flu season, wildfire smoke events, and industry-specific surges all push usage above your normal baseline, often with little warning.
Order Quantity: How Much to Actually Buy
The reorder point tells you when to place an order. It does not tell you how much to order once you have hit that point, which is really what the title of this guide is asking.
Order quantity = expected usage during the planning period + desired ending safety stock, minus current usable inventory, minus any incoming inventory already on order
Worked example, using the same 22-operating-day warehouse from earlier, planning for the next operating month:
- Expected usage over 22 operating days: 40 x 22 = 880 masks
- Desired ending safety stock, at 4 days of usage as a slightly larger cushion for month-end: 40 x 4 = 160 masks
- Current usable inventory: 400 masks
- Incoming inventory already on order: 200 masks
- Order quantity: 880 + 160, minus 400, minus 200 = 440 masks
Reorder point and order quantity answer two different questions. Reorder point tells you when to buy. Order quantity tells you how much. Both come from the same underlying daily usage number, so once you have that, you have what you need for either calculation.
Build Your Own PPE Reorder Point Calculator
You do not need inventory software to run any of this. A basic spreadsheet with a handful of inputs does the job. Here is the worked example above laid out as a template:
| Input | Example value |
|---|---|
| PPE users per day | 40 |
| Units per user per shift | 1 |
| Shifts per day | 1 |
| Operating days per month | 22 |
| Daily usage | 40 |
| Lead time | 2 business days |
| Safety stock (2 days) | 80 |
| Reorder point | 160 |
Multiply users per day by units per shift by shifts per day for your daily usage. Multiply that by lead time for lead time demand, then add your chosen safety stock for your reorder point. Update the users per day figure monthly, or whenever headcount changes meaningfully, and the calculator stays accurate without ongoing maintenance.
How Much PPE Should a Business Keep in Stock Overall
Your reorder point should cover the PPE you expect to use during supplier lead time, plus your safety stock. Businesses with higher exposure risk, such as healthcare facilities or any workplace with seasonal demand spikes, often carry a larger standing reserve than a business with steady, predictable usage.
A large hospital will generally have significantly higher PPE demand than a small clinic, simply due to workforce size, patient volume, and the number of departments running at once. The formula scales the same way regardless of size. What changes is the daily usage number you plug in, not the underlying math.
Common PPE Ordering Mistakes
- Ordering against total headcount instead of actual daily users: Not everyone on payroll uses PPE every day.
- Ignoring shift differences: Uneven staffing across shifts means a single average will not reflect real usage.
- Using calendar days when the business actually operates on workdays: A 30-day estimate and a 22-workday estimate can differ by a few hundred units.
- Treating reorder point as if it were order quantity: One tells you when to buy; the other tells you how much.
- Ignoring incoming inventory already on order when calculating a new order, which leads to overbuying.
- Keeping no safety stock at all to save money, then facing a shortage the moment a delivery runs late.
- Assuming a generic N95 consumption rate instead of following manufacturer instructions and your own organization's respiratory protection procedures.
- Ignoring glove sizing needs and ordering one size across a team that actually needs a mix.
Frequently Asked Questions
How much PPE to order per employee?
It depends on their role, not just their headcount. Identify how many masks or gloves that employee actually uses per shift based on your organization's own observed usage, multiply by the number of shifts they work, and add your chosen safety stock. There is no single per-employee number that applies across every job type.
What is the PPE reorder point formula?
Reorder point equals average daily PPE usage multiplied by your supplier's lead time, plus safety stock. Once your on-hand inventory drops to that number, it is time to place your next order.
How many N95 masks does one employee need per week?
Multiply that employee's actual daily usage, based on your organization's observed rate and any applicable respiratory protection requirements, by the number of days they work that week. There is no universal per-week number, since replacement frequency depends on manufacturer instructions and workplace conditions.
How much safety stock should I keep for masks and gloves?
A simple approach is to choose some days of average usage, commonly 2 to 5 days depending on supplier reliability and how much risk you are comfortable carrying, and hold that as your buffer. There is no universal PPE safety stock percentage.
Do shift patterns affect how much PPE I should order?
Yes. A facility running multiple shifts can use substantially more PPE than a single-shift operation, but the exact difference depends on how many employees work each shift and how much each of them uses, not simply the number of shifts.
Is there a standard PPE usage rate that applies to every industry?
No. Usage per shift varies by role and industry. Base your calculation on your own observed usage data rather than a generic industry average, and for N95 respirators, follow the manufacturer's instructions and your organization's respiratory protection program.
Match Your Usage to the Right Pack Sizes
Once you know your numbers, Hakeem PPE stocks NIOSH-approved N95 respirators and powder-free nitrile gloves in box, case, and pallet quantities, with delivery typically running 1 to 3 business days from our Las Vegas warehouse. If you would rather work through your specific numbers with someone directly, our team can help on a short call.
Shop N95 Masks Shop Nitrile Gloves Book a MeetingFor the full buyer's guide on ordering in bulk, verifying certification, and choosing a supplier, see our Business Buyer's Guide to Ordering N95 Masks and PPE in Bulk.