OneTaskBy Tim King · Updated
Fill Rate Calculator
Unit, Order and Line Fill Rate Formula From Units Ordered and Shipped
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How the Fill Rate Calculator works
This fill rate calculator measures how much of each order you shipped. Enter how many units customers ordered over a period and how many you actually shipped, and the calculator gives the unit fill rate and the shortfall. Add the order count and how many orders went out complete for the order fill rate, and the line counts for the line fill rate. All three are percentages of demand met from stock on the first attempt, and the difference between them is where the operational story is.
Fill rate calculator: shipped against ordered
Fill rate is the share of customer demand that was satisfied immediately from stock, without a backorder, a substitution or a partial shipment. It is the customer's view of your inventory: not whether you had stock on the shelf on average, but whether it was there when the order arrived. There are three versions and they answer different questions.
Unit fill rate is units shipped divided by units ordered. It is the easiest to compute and the most forgiving, because one large order that ships in full can hide dozens of small ones that did not. Use it for wholesale and manufacturing where a customer ordering 1,000 of something and receiving 950 is a minor irritation.
Order fill rate is the number of orders shipped complete divided by orders received. An order counts only if every line on it shipped in full, so a single missing item fails the whole order. This is the number that matters in e-commerce and retail replenishment, where the customer experiences the order, not the unit, and a partial shipment means a second delivery, a second box and often a refund. It is always the lowest of the three.
Line fill rate sits in between: the share of order lines, each being one SKU on one order, that shipped in full. It tells you which products are causing the problem, which the unit rate obscures and the order rate does not break down. A 97% unit fill rate with a 90% line fill rate means the shortages are concentrated in low-volume SKUs, which is the usual pattern and the usual place to put safety stock.
Fill rate versus service level. Planners sometimes quote a cycle service level, which is the probability of not running out during a replenishment cycle. It is a stocking policy input, not a customer outcome. Fill rate is what the customer saw. A 95% cycle service level often produces a unit fill rate above 98%, because stockouts that do occur affect only the tail of the cycle's demand.
What is a good fill rate? Grocery and consumer goods suppliers are typically held to 98% or better by retailers, with penalties below that. Industrial distributors commonly run 92% to 97% on lines. Direct-to-consumer brands should be looking at order fill rate above 95%, since every miss is a customer contact. Raising fill rate from 95% to 99% costs far more inventory than raising it from 85% to 95%, because the last percentage points cover the demand spikes safety stock exists for, so the target should be set against the margin and the customer's tolerance rather than chasing 100%.
Fill rate table by units shipped
An order book of 10,000 units, with shipped units rising in steps of 50.
Unit fill rate and units short on 10,000 units ordered
| Units shipped | Unit fill rate | Units short |
|---|---|---|
| 8,800 of 10,000 | 88.0% | 1,200 |
| 8,850 of 10,000 | 88.5% | 1,150 |
| 8,900 of 10,000 | 89.0% | 1,100 |
| 8,950 of 10,000 | 89.5% | 1,050 |
| 9,000 of 10,000 | 90.0% | 1,000 |
| 9,050 of 10,000 | 90.5% | 950 |
| 9,100 of 10,000 | 91.0% | 900 |
| 9,150 of 10,000 | 91.5% | 850 |
| 9,200 of 10,000 | 92.0% | 800 |
| 9,250 of 10,000 | 92.5% | 750 |
| 9,300 of 10,000 | 93.0% | 700 |
| 9,350 of 10,000 | 93.5% | 650 |
| 9,400 of 10,000 | 94.0% | 600 |
| 9,450 of 10,000 | 94.5% | 550 |
| 9,500 of 10,000 | 95.0% | 500 |
| 9,550 of 10,000 | 95.5% | 450 |
| 9,600 of 10,000 | 96.0% | 400 |
| 9,650 of 10,000 | 96.5% | 350 |
| 9,700 of 10,000 | 97.0% | 300 |
| 9,750 of 10,000 | 97.5% | 250 |
| 9,800 of 10,000 | 98.0% | 200 |
| 9,850 of 10,000 | 98.5% | 150 |
| 9,900 of 10,000 | 99.0% | 100 |
| 9,950 of 10,000 | 99.5% | 50 |
| 10,000 of 10,000 | 100.0% | 0 |
Fill rate formula and worked examples
The formula: unit fill rate = units shipped ÷ units ordered × 100; order fill rate = complete orders ÷ total orders × 100; line fill rate = lines shipped in full ÷ lines ordered × 100.
First example. customers ordered 5,000 units and you shipped 4,850. Unit fill rate is 97%, with a shortfall of 150 units.
Second example. of 400 orders, 360 went out complete, an order fill rate of 90%. The gap between 97% and 90% shows the shortages were spread across many orders rather than concentrated in a few.
How many units short is acceptable? Many retailers target 95–98% unit fill rate; order fill rate is always the lowest of the three because a single missing line fails the whole order.
FAQ
What is the fill rate formula?
Fill rate is quantity fulfilled divided by quantity ordered, expressed as a percentage. For unit fill rate use units, for order fill rate use orders shipped complete over orders received, and for line fill rate use order lines shipped in full over total order lines.
Why is my order fill rate so much lower than my unit fill rate?
Because an order fails if any one line on it is short. If orders average five lines and each line has a 97% chance of shipping in full, only about 86% of orders ship complete. Multi-line orders amplify small line-level shortages into large order-level misses.
Is fill rate the same as on-time in-full?
No. OTIF adds a delivery-date condition: the order must be complete and arrive on the agreed day. Fill rate measures only whether stock was available to ship. An order can fill at 100% and still fail OTIF because the carrier was late.
Should backorders count as fulfilled?
Not in the fill rate. The measure is demand met from available stock at the time of the order. Backordered units that ship later are counted against the period in which they were ordered, as a shortfall, which is what makes fill rate a stock-availability measure rather than an eventual-delivery one.
How often should fill rate be measured?
Weekly for operational control and monthly for reporting, always by SKU as well as in total. A single overall figure hides which products are short, and the line fill rate by SKU is the list you take into the next replenishment review.
See also: all Profit & Growth tools, Rates & Pricing, Invoicing & Payments.
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