Order Fill Rate: Measure How Many Orders Ship Complete
Order fill rate shows the share of customer orders that ship in full from available stock by the promised ship date. Measure the whole order so one missing item does not disappear inside a high unit count.
Eight short lines affected eight complete orders.
Your warehouse ships 396 of 410 ordered units this week. A 96.6% unit result looks healthy. Those 14 missing units sit across eight customer orders, so eight people receive a split shipment, a delay, or a cancellation.
Order fill rate measures that customer-level result. It asks how many eligible orders shipped complete on the first promised shipment. The metric turns scattered stockouts and short picks into one number you can trace back to a SKU, location, and operating cause.
Define a filled order before you count one
A filled order contains every required item and quantity, shipped by the promised ship date from stock available to the fulfillment operation. If one line is short, the order is incomplete. Shipping the missing item later can recover the sale, but it does not change what happened on the first shipment.
Write the rule before pulling data. Decide how you will handle customer cancellations, fraud holds, preorders, digital products, subscription orders scheduled for a later date, and orders the customer edits after checkout. Exclude records that never entered the fulfillment promise. Keep eligible orders that failed because stock or warehouse execution could not complete them.
Shopify separates unfulfilled, in progress, on hold, partially fulfilled, and fulfilled statuses. A partially fulfilled order has only some items fulfilled, while a fulfilled order has all items shipped. Those statuses help build the source data, but your fill-rate calculation still needs a date rule. An order marked fulfilled three days late missed a next-day ship promise.
Shopify's order status guide documents the fulfillment states and their meanings.
Calculate complete orders against one fixed cohort
The formula is orders shipped complete by the promised ship date / total eligible orders x 100. Shopify describes order fill rate as the percentage of orders fulfilled completely and on time without stockouts or backorders.
Use a cohort based on when orders entered fulfillment, then wait long enough to judge the promise. For example, review all orders released Monday through Sunday after the last Sunday order reaches its promised ship cutoff. This prevents late-week orders from looking incomplete only because the warehouse has not had time to process them.
Do not calculate the numerator from today's final status while using last week's order count as the denominator. A backorder completed this week would rewrite last week's result. Preserve the first-shipment outcome, then track eventual completion, cancellation, and refund as separate recovery measures.
Shopify's fill-rate guide gives the same complete-orders-over-total-orders formula and distinguishes order fill rate from line fill rate.
Read order, line, and unit fill rates together
Order fill rate answers whether each customer received a complete first shipment. Line fill rate measures the share of order lines filled in full. Unit fill rate measures the share of requested units shipped. Each denominator answers a different operating question.
Use order fill rate for the customer experience. Use line fill rate to find how often a SKU line fails. Use unit fill rate to measure the physical volume supplied. A brand can post strong line and unit results while many multi-item orders still arrive incomplete.
Keep the definitions strict. A line for three bottles counts as filled only when all three ship under a complete-line rule. Two shipped bottles still contribute two units to unit fill rate, but the line and the order remain incomplete. This is why the three rates should not be compared as if they were interchangeable grades.
A 100-order week for an apparel brand
Consider a hypothetical apparel brand that releases 100 orders to its 3PL in one week. The orders contain 230 product lines and 410 units. Ninety-two orders ship complete by their promised date. Eight orders have one short line because a popular size appears available in the store but is missing from the 3PL bin.
The order fill rate is 92 divided by 100, or 92%. The warehouse fills 222 of 230 lines in full, which produces a 96.5% line fill rate. It ships 396 of 410 units, which produces a 96.6% unit fill rate.
The line and unit figures show that most demand moved. The order figure shows that one in twelve customers did not receive a complete first shipment. The gap points to a concentrated availability problem rather than broad warehouse failure.
The operator then groups the eight failed orders by SKU and location. Six involve the same black medium sweatshirt. The inventory system shows 18 available units, but a controlled bin count finds four. Two other orders failed because the picker could not find units stored under the wrong bin label. The brand now has two actions: reconcile the sweatshirt count and fix the location record.
Improve the cause behind incomplete orders
A fill-rate report should keep the failed orders visible. Tag the first reason that prevented a complete shipment: unavailable stock, inventory mismatch, short pick, damaged stock, allocation rule, or an order hold released after the promise. Use a small reason set that an owner can act on.
Review the metric by SKU, fulfillment location, and order type. A sitewide average can hide one variant that breaks many bundles. It can also hide a location that shows stock in software but cannot pick it. The failed-order list should connect each percentage point to the exact order lines behind it.
Choose the fix that matches the cause. Inventory mismatches need tighter receiving, cycle counts, and adjustment controls. Repeated stockouts may require a new reorder point or safety-stock rule. Warehouse short picks need bin accuracy, picking controls, or a location process change. Split shipments caused by allocation rules need a policy decision about whether to hold complete orders or ship available items first.
Track recovery separately. Record whether the missing item shipped later, the customer accepted a substitution, or the team canceled and refunded the line. Recovery matters, but it should not erase the first failure. Keeping both results shows whether you prevent incomplete orders and how well you handle the ones that remain.
Run the same order fill review every week
Keep the cohort, first-shipment rule, and failure reasons stable so the rate leads to an operating decision.
Where ShopDucky fits
ShopDucky can compare orders, inventory availability, fulfillment events, and warehouse exceptions across the tools your team already uses. An AI employee can calculate the weekly order fill rate, group incomplete orders by SKU and reason, and prepare the highest-impact fixes for your operations owner to approve. See the store operations workflow.
Order fill rate, answered
What is order fill rate in ecommerce?+
Order fill rate is the percentage of customer orders that ship complete from available stock by the promised ship date. One missing item makes the whole order incomplete for this measure.
What is the order fill rate formula?+
Divide orders shipped complete by total eligible orders, then multiply by 100. If 92 of 100 eligible orders ship in full by the promised date, the order fill rate is 92%.
Is fill rate the same as on-time delivery?+
No. Fill rate asks whether the complete order could ship from available stock by the promised ship date. On-time delivery asks whether the carrier delivered the shipment by the customer-facing delivery promise.
Should backorders count as filled orders?+
A later backorder shipment should not change the original order fill result. Track eventual completion separately so you can see both the first customer experience and the final recovery.
