Basic inventory management for small businesses

Picture a customer walking in, asking for your best-selling product, and you having to say it's out of stock. Or the opposite: you open a box in the back room and find merchandise you bought a year ago that nobody has touched. Both scenes hurt, and both are inventory problems. Inventory isn't just "the stuff I have on hand." It's money you paid up front that's still sitting there, frozen, waiting to turn into a sale.

The good news is you don't need expensive software or a logistics degree to get your inventory under control. You need four basic ideas and the discipline to review them on a schedule. Let's take them one at a time.

Why inventory is money, not shelving

Every product you have stored represents cash that already left your account. Until it sells, that money isn't working for you: it doesn't pay the rent, cover payroll, or let you buy the things that actually move fast. That's why inventory has two opposite enemies. Hold too little and you lose sales and customers who don't come back. Hold too much and you tie up your cash, with the added risk that goods expire, get damaged, or go out of style.

Perfect inventory doesn't exist; enough inventory, the kind that covers demand without choking your cash flow, does.

Everything below is a way to get closer to that middle ground: having just enough of what moves, and not piling up what sits.

Par levels: your warning line

A par level is the lowest amount you let a product fall to before reordering. Think of it like the reserve mark on a fuel gauge: when you hit it, you know it's time to fill up before you get stranded.

To set one, look at how much of that product you sell during the time it takes your supplier to restock you, then add a cushion. If you sell 10 units a week and your supplier takes a week to deliver, your par level can't be 10: you have to reorder before dropping below that number, or you'll be at zero the day the truck arrives. Write down a par level for your most important products and revisit it each season.

FIFO: first in, first out

FIFO stands for "first in, first out." The rule is simple: the oldest stock sells before the newest. It's obvious with products that expire (food, cosmetics, medicine), but it also applies to anything that goes out of fashion or changes versions.

In practice, FIFO is mostly about how you physically arrange things. When new stock arrives, it goes in the back; the old stock gets pulled to the front. A few rules that help:

• Label each batch with the date it came in, even if it's just with a marker.
• Put the newest stock behind and the oldest within easy reach.
• Check expiration dates once a week with a quick walk through the storeroom.
• Train whoever restocks not to "top off from above" and bury the old stock.

A storeroom run on FIFO avoids the classic sad discovery of the expired box in the corner.

ABC analysis: not everything deserves the same attention

Not all your products matter equally. ABC analysis starts from an idea you hear often in business: roughly 20% of your products tends to generate about 80% of your revenue. Sort them into three groups:

• A: the few products that bring in most of the money. Watch them closely, count them often, and never let them run out.
• B: the in-between ones, important but not critical. Regular review, no obsessing.
• C: the many products that contribute little. Don't burn energy counting them every week; an occasional glance is enough.

The point of ABC is that it tells you where to put your limited attention. If you're a one-person shop or have a small team, you can't care for 300 SKUs with the same devotion. Take care of the A's first.

The reorder point: when to press the order button

The reorder point answers a concrete question: at exactly what quantity should I place a new order? The basic formula experts recommend is: reorder point = (average daily sales × supplier lead time in days) + safety stock.

Safety stock is that extra cushion for when sales spike or the supplier runs late. If you sell 5 units a day, your supplier takes 4 days, and you want a cushion of 10 units, your reorder point is (5 × 4) + 10 = 30. When you drop below 30, you order. That way you don't rely on memory or on the panic of seeing an empty shelf.

How to start this week

Don't try to roll out all four tools at once. Start with the simplest move: make a list of your products, mark which ones are A (the ones that bring in the most money), and give those a par level and a reorder point. That alone will stop you from losing sales to stockouts and curb impulse buys of things that don't move.

Well-run inventory goes unnoticed: it's the quiet difference between a business that always has what the customer is looking for and one that lives apologizing. And that difference, repeated every single day, is what keeps your cash healthy.

Sources

• Square — https://squareup.com/us/en/the-bottom-line/operating-your-business/how-to-do-effective-inventory-management-for-small-business
• NetSuite (ABC Analysis) — https://www.netsuite.com/portal/resource/articles/inventory-management/abc-inventory-analysis.shtml
• NetSuite (Safety Stock) — https://www.netsuite.com/portal/resource/articles/inventory-management/safety-stock.shtml
• Cin7 — https://www.cin7.com/blog/inventory-management-techniques/
• Saylor Academy / Lumen Operations Management — https://courses.lumenlearning.com/suny-opmanagement/chapter/9-1-inventory-management/