Fill Rate

Fill rate is the percentage of a customer's demand that is met directly from available stock, without shortages or backorders. It is one of the core indicators of a supply chain's service level: it answers the question of what fraction of what the customer ordered you were able to deliver right away.

It is calculated by comparing what was delivered against what was ordered, and the reading changes depending on the unit of measure: by units, by order lines or by complete orders. A high fill rate indicates that inventory is properly sized for real demand; a low one signals stockouts, poor replenishment planning or supply problems. As a traceability metric for the order flow, it is part of the operational visibility that Trazzo provides.

Unlike measuring only whether a delivery happened or not, fill rate quantifies the degree of fulfillment, which makes it more actionable for detecting where service is being lost in the chain.

Fill rate measures how much of total customer demand is covered from inventory on hand, at the moment it is needed. It is a service level metric: it does not only care whether the order arrived, but what portion of what was requested could be shipped without shortages. In consumer goods, distribution and logistics in Argentina and the region, where product availability on the shelf or in the warehouse drives revenue, fill rate is one of the most closely watched operational KPIs.

How it is calculated

The base formula is simple: units delivered divided by units ordered, expressed as a percentage. What matters is the unit of measurement, because it changes how severe the number is:

• By units (item fill rate): if the customer ordered 1,000 cases and you delivered 950, the fill rate is 95%. It is the most granular reading.
• By order lines (line fill rate): it measures what percentage of an order's lines was completed at 100%. An order with 10 SKUs where 9 shipped complete gives 90%.
• By complete order (order fill rate): the most demanding; it only counts orders shipped in full, without a single shortage. A 10-line order where just one line failed counts as an unfulfilled order.

That is why the same shipment can show 96% by units but 70% by complete orders: a small shortfall spread across many orders sinks the order fill rate. Defining which unit the company measures is the first step to avoid comparing apples and oranges.

Why it matters

Fill rate has a direct impact on revenue and on the customer relationship. Every fill rate point lost is a sale that did not happen (sales lost to stockouts) and, in retail or consumer goods chains, it is often penalized by contract: many large buyers apply fines or deductions when the supplier falls below an agreed threshold. In addition, a low fill rate erodes trust and pushes the customer to look for alternative sources of supply.

Internally, it is a barometer of inventory health: it reveals whether safety stock is properly calibrated, whether replenishment arrives on time and whether the demand forecast is accurate. A consistently low fill rate almost always points to one of those three fronts.

A concrete example

A beverage distributor in Greater Buenos Aires receives an order from a supermarket for 12 SKUs. It has full stock of 10, is short 40 cases of one, and the last one is completely out of stock. By lines, its fill rate is 83% (10 of 12 lines complete). If the supermarket measures by units and the shortfall represents 6% of the volume, the item fill rate is 94%. The buyer, however, evaluates by complete order: since it did not arrive in full, that order counts as unfulfilled. The same delivery looks very different depending on the rule, and that is where the fines come from.

Fill rate vs OTIF

Fill rate is often confused with OTIF, but they measure different and complementary things:

In practice, fill rate is one component of OTIF: the In Full part. A delivery can have a perfect fill rate but fail OTIF because it arrived late.

Common mistakes

• Not setting the unit of measurement: comparing a unit-based fill rate from one period against a complete-order fill rate from another leads to false conclusions.
• Confusing fill rate with on-time delivery rate: they are different axes; a product can be available (good fill rate) and still arrive late.
• Averaging without segmenting: an overall fill rate of 95% can hide that a key customer or a star SKU is at 70%. It is worth looking at it by customer, channel and product.
• Chasing 100% at any cost: raising fill rate by inflating inventory without analysis costs tied-up capital; the goal is the balance between service and stock cost.

Measured well and segmented, fill rate is one of the clearest levers for diagnosing where the supply chain is leaving sales on the table.