Order Accuracy: What 99.5% Costs You Every Month

At 5,000 orders a month, 99.5% order accuracy means 25 customers get the wrong order every month. Every fulfillment provider quotes an accuracy number, and very few multiply it against your volume for you. Do the multiplication yourself before you compare providers.

How do you calculate order accuracy rate?

Order accuracy rate is the share of orders that shipped with nothing wrong:

Order accuracy rate = error-free orders ÷ total orders shipped × 100

Say you shipped 5,000 orders last month and 25 of them had an error. That leaves 4,975 error-free orders, and 4,975 ÷ 5,000 × 100 = 99.5%.

Count bad orders, not individual mistakes. An order with a wrong item and a missing item is one bad order. If those 25 mistakes landed in 20 orders, the rate is 4,980 ÷ 5,000 × 100 = 99.6%.

Order error rate is the same math from the other side: orders with an error ÷ total orders shipped × 100. At 99.5% order accuracy the error rate is 0.5%, or 25 orders out of 5,000.

How many mistakes does each accuracy rate mean per month?

Take three order volumes and three accuracy rates. One mistake means one customer who didn't get what they ordered.

The 99.5% shop and the 99.9% shop sound alike on a website. At 20,000 orders a month, one of them is apologizing to 100 customers and the other to 20.

KSP sits in the last column: 99.999% order accuracy across 32.1M orders. At 5,000 orders a month, that's one wrong order every 20 months.

How is order accuracy different from picking accuracy and perfect order rate?

3PLs quote several metrics as accuracy, and each one divides by something different:

• Picking accuracy counts picks: correct picks ÷ total picks × 100. It checks that the right unit came off the shelf. A correct pick that ships short or to the wrong address still counts as accurate.
• Order accuracy rate counts whole orders: the right items, in the right quantities, to the right address, with nothing missing. It's the number your customer feels, because they only see the box that arrives.
• Perfect order rate is stricter. An order only counts if it's accurate, shipped on time, arrived undamaged and carried the right paperwork, such as the packing slip and labels. It always sits at or below order accuracy, because each extra condition is another way to miss.
• Order error rate is 100 minus the order accuracy rate.

The denominator changes the number. Take 5,000 six-item kits, which is 30,000 picks. If 25 kits each have one wrong unit, picking accuracy is 29,975 ÷ 30,000 × 100 = 99.92%, and order accuracy is 99.5%. Both numbers describe the same 25 customers.

KSP's 99.999% is order accuracy, not picking accuracy.

What counts as an order error?

Any shipping error that makes the delivered order different from what the customer bought:

• The wrong item, including the wrong size, color or flavor of the right product
• A missing item or a short quantity
• An extra item, which is a unit you lose
• A missing insert, or a kit built without one of its components
• The wrong address or the wrong shipping label
• Damage from packing, such as a box too weak for what's inside

Carrier damage in transit and late deliveries tend to land in shipping accuracy or perfect order rate instead. Ask which bucket a provider puts them in before you compare two quoted rates. Our comparison of nine ecommerce 3PLs lists the accuracy figure each one publishes and what it counts.

What is a mispick, and what causes picking errors?

A mispick is a picking error: the picker pulls the wrong item, the wrong variant or the wrong quantity for an order line. If nothing catches it before the box is sealed, it ships as a wrong order.

Mispicks cluster in a few spots on the warehouse floor:

• Look-alike SKUs, such as sizes, colors or flavors of one product stored side by side
• Pick lists worked from paper or memory, with nothing checking the unit against the order
• Kits and bundles, where every extra component is one more pick to get wrong
• Inventory sitting in the wrong slot, so the picker grabs whatever is in the location the system named

How do you improve order picking accuracy?

Put a check on every pick, then set up the shelves so the wrong unit is hard to grab:

1. Scan every pick. The scanner flags any unit whose barcode doesn't match the order line, before it reaches the box. That catches the wrong size or flavor even when it looks and weighs the same as the right one.
2. Separate look-alike SKUs. Store sizes, colors and flavors of one product apart, so reaching one slot over doesn't land on a near match.
3. Keep slot counts right. Regular cycle counts catch inventory sitting in the wrong location before a picker pulls from it.
4. Check kits against the build list. Confirm every component of a kit or bundle, because each one is a separate pick.
5. Weigh at packing as a backup. A weight check catches a missing or extra unit that got past the pick. It misses variants that weigh the same, so it can't replace the scan.

What does one wrong order cost?

A wrong shipment costs you in four places:

1. The reship. Product cost twice, shipping twice, and on a promotion or subscription box, sometimes a full replacement build.
2. The refund or credit your CX team issues to keep the review. The discount code you send afterward is a cost nobody counts.
3. The support time. The customer emails you, not the warehouse. Your team chases the pick ticket and the carrier, even though the warehouse made the mistake.
4. The customer you lose without hearing about it. Subscription customers don't always complain. They cancel. Retail buyers remember which vendor's cartons had errors when the next program gets assigned.

A brand shipping 5,000 orders a month at 99.5% pays for about 25 of these every month.

Across a whole warehouse the losses run larger. A Vanson Bourne survey fielded in 2012 put the average distribution center's mispick losses at nearly $390,000 a year. Conexiom's 2024 survey put a single B2B order error at $17,800 once make-good cost and customer churn are counted. Both figures, with their sources, are in our roundup of what mispicks and bad orders cost.

How do you get the real order accuracy rate from your 3PL?

Five questions get you most of the way:

• How is every pick checked against the order? Ask for the mechanism: a barcode scan, a weight check, a person with a clipboard.
• What happens when someone scans the wrong item?
• Does the number measure the pick or the whole order, and what's the denominator? Pick accuracy can look perfect while a box still ships short or goes to the wrong address. Orders shipped, orders picked, lines and units each give a different rate.
• Which errors are left out of the count? Get the exclusions in writing, so one provider's 99.9% compares fairly with another's.
• If you lose or damage a unit, who pays for it?

Then check the number on more than one page of the provider's own site. Some 3PLs list one accuracy rate on the homepage and a different one on another page. Ask which number goes in the contract.

At KSP, every pick gets an RF barcode scan, and the result is 99.999% order accuracy across 32.1M orders. If KSP loses or damages a unit, KSP pays its cost. Speed comes from separate equipment: 60 Locus robots bring inventory to the pickers, an order gets picked and packed in under 30 minutes, and orders in by 2 PM CST ship the same day. When you tour the building, ask to watch a pick get scanned.

Then check any provider against your own data. Pull 90 days of refund and reorder reason codes, count every wrong item, missing item and damaged-in-transit, and divide by orders shipped. That's your delivered accuracy, whatever the provider's dashboard says. Track it monthly as a KPI next to the rate your 3PL reports.

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