Available, Reserved and On-Hand Stock: The 3 Numbers Every SME Must Tell Apart

Why a single "stock quantity" isn't enough

In many SMEs, stock is still read as a single number: whatever is on the shelf, or in one spreadsheet column. That figure answers one question — how many units are physically there — and leaves unanswered the ones that actually matter at the moment of selling: how many can I still promise, and how many are already committed elsewhere?

Those are three different questions with three different answers. Telling them apart avoids two opposite, equally costly mistakes: promising goods that are no longer available, or turning down a sale on stock that is, in fact, still there to sell.

The three numbers to tell apart

On-hand (physical) stock

What is physically sitting in the warehouse, countable at stocktake. It's the simplest figure to measure, and the least useful on its own: it says nothing about what's already promised to another customer.

Reserved stock

The portion of on-hand stock already committed — to a confirmed order, a warehouse transfer in progress, or a manual hold. This stock exists, but it is no longer for sale.

Available stock

What is genuinely left to promise to a new customer: on-hand stock, minus what's reserved. It's the only one of the three numbers that should appear at the moment a sale is confirmed.

What moves these three numbers

A confirmed customer order reserves stock without taking it out: on-hand stays the same, available goes down. Delivery, on the other hand, actually removes the goods: on-hand drops in turn, and the associated reservation disappears because it has been fulfilled.

• Supplier receipt — increases on-hand stock, and available stock along with it, as soon as goods are actually received into the warehouse.
• Partial delivery — only releases the delivered portion; the rest of the order keeps reserving the remaining balance until fully delivered.
• Cancelled order — immediately releases the associated reservation; available stock goes back up without any goods moving at all.
• Customer return — increases on-hand stock once the goods are physically back in, not the moment a return is merely announced.
• Inventory adjustment — corrects on-hand stock to reflect a physical count, up or down, independent of any order.

A concrete example

A wholesaler has 120 units of one item in the warehouse. Two confirmed orders cover 35 and 20 units, due for delivery next week: 55 units are reserved. On-hand stock stays at 120, but available stock is only 65. A sales rep promising 80 units to a third customer is reading the wrong number — on-hand, not available — and finds out at delivery time, not at the moment of the sale.

Conversely, if that same wholesaler receives a supplier delivery of 40 units before either order is due, available stock jumps to 105 the moment it's received, without waiting for the pending orders to be fulfilled.

What the confusion actually costs

Confusing on-hand with available produces overselling: the customer finds out their order can't be honoured, often after it was confirmed. Confusing reserved with unavailable produces the opposite — a rep turns down a sale on stock that will, in fact, become available again the moment an earlier order is cancelled or changed.

Both mistakes share the same root: a single figure shown where three different questions are actually being asked. A product catalogue that doesn't distinguish between these levels passes the confusion on to the whole sales team, however careful they are.

A practical checklist

• Does your sales team see available stock, or only on-hand stock?
• Does a confirmed order reserve stock immediately, before delivery is even prepared?
• Does a cancelled order release its reservation without manual intervention?
• Does a partial delivery release only the delivered quantity, not the whole order?
• Is an inventory adjustment logged, with its reason and who made it?

If any of these come back "no," the problem isn't counting accuracy — it's the absence of a distinction that on-hand stock alone can never carry.