Inventory accuracy: How to measure it and improve it in your warehouse

Inventory accuracy measures how closely physical stock matches system records in your inventory management system. Teams should keep an eye on it and maintain a high accuracy rate. If they aren’t careful, small discrepancies can compound into stockouts, fulfillment errors, and wasted labor at scale. Read on to learn what inventory accuracy is, how to measure it, why it breaks down, and how to improve it.

What is inventory accuracy?

Inventory accuracy is a key performance indicator (KPI) reflecting the alignment between recorded inventory and the actual physical stock on hand in your warehouse. Higher inventory accuracy means more reliable financial reporting, smoother operations, and improved decision-making for purchasing and forecasting.

The importance of inventory accuracy

Companies calculate inventory accuracy to ensure their product availability meets customer demand. Knowing the rate also helps them optimize costs and prevent waste.

If inventory systems aren’t accurate, companies can suffer many setbacks, including:

• Stockouts and overage: Inventory inaccuracies can lead to lost sales from ghost inventory or trapped capital from over-purchasing.
• Increased carrying costs: Companies with low inventory accuracy may incur carrying costs that are three times higher than those of industry leaders.
• Operational bottlenecks: Inventory inaccuracies can make it harder for staff to look for items. As such, they may spend more time and energy looking for misplaced items and processing rush shipments.

Companies experiencing less-than-ideal inventory accuracy should correct it as soon as possible. Research has revealed that around 60% of SKUs are affected by inventory record inaccuracies, and correcting these inaccuracies can lead to a 4-8% increase in sales.

How to measure inventory accuracy

There are two formulas for measuring inventory accuracy.

Inventory accuracy rate formula

If you’re a small to medium-sized business that needs to know how much physical stock you have in the building to fulfill customer orders, use the inventory accuracy rate formula. It shows the percentage of SKUs that match your system records:

Inventory Accuracy = (Total Counted Units / Total Recorded Units) X 100

To demonstrate how this formula works, imagine you own a retail store for purses. Before placing a new order with your supplier, use this formula to check the accuracy of your inventory data for a popular purse style. To determine the total number of units counted, log in to your multi-warehouse inventory management software. The dashboard states you have 2,000 of this purse on the shelves. Then, your team goes to the stockroom to physically count every one of those purses. They find only 1,970 sitting on the shelves. This is what you get when you plug in these numbers into the formula:

Inventory Accuracy = (1,970 / 2,000) X 100
Inventory Accuracy = 98.5%

Your inventory accuracy rate is 98.5%, which is considered solid. A good inventory accuracy rate typically ranges from 95% to 98%, with top-tier operations aiming for at least 99%. Rates below 95% indicate that operations need immediate intervention and are at risk of severe issues such as delayed orders and stockouts.

While this rate is good, it does indicate that 1.5% of your stock data is incorrect, so you would need to investigate the missing 30 purses before they affect customer orders.

Absolute variance formula

If you’re running a large warehouse or supply chain or a business with high-value goods, use the absolute variance formula. It measures inventory degradation over time and exact shrinkage costs, and can help you generate highly precise accounting reporting:

Variance Accuracy = [1 – (Sum of Absolute Variances / Total Recorded Inventory) ] X 100

To see how this calculation works, suppose you manage a small warehouse that stocks three types of clothes: hoodies, sweatshirts, and T-shirts. At the end of the month, you compare your actual stock against what your inventory software records. You find:

• Hoodies: Software says 400, but you only find 380
• Sweatshirts: Software says 300, but you only find 230
• T-shirts: Software says 250, but you only find 240

Next, add up the inventory amounts that your software recorded:

400 (hoodies) + 300 (sweatshirts) + 250 (T-shirts) = 950 total recorded inventory

Then, calculate the absolute variances. A variance is the difference between the physical count and the recorded software inventory. Absolute variance in the formula means that you ignore negative signs because any error, whether a shortage or overage, reduces accuracy:

• Hoodies variance: 380–400 = absolute variance = 20
• Sweatshirts variance: 230–300 = absolute variance = 70
• T-shirts variance: 240–250 = absolute variance = 10
• Sum of absolute variances: 20 + 70 + 10 = 100 total units in error

You can now plug these two totals into your formula:

Variance Accuracy = [1 – (Sum of Absolute Variances / Total Recorded Inventory) ] X 100

Variance Accuracy = [1 – (100 / 950) ] X 100

Variance Accuracy = 89.5%

Your variance accuracy is 89.5%, which falls short of the 95% benchmark, and you have a 10.5% total error rate across your stock.

What causes inventory inaccuracy?

Inventory accuracy stems from several factors, including:

• Receiving errors, which can introduce discrepancies at the point of intake
• Manual data entry mistakes across picking and putaway, such as typos or skipped scans
• Untracked shrinkage, which refers to unrecorded inventory loss due to employee theft, damage, mislabeling, or misplacement
• Outdated or siloed inventory records that don’t reflect real-time movements

Each cause is a compounding problem that can create a chain of downstream inaccuracies, so it’s vital for teams to catch these errors early on.

Improve inventory accuracy with Logiwa IO

How to improve inventory accuracy in your warehouse

To improve inventory accuracy in your warehouse, consider adopting the following best practices:

• Implement an inventory management software (IMS): A centralized IMS gives every team member visibility into the same real-time inventory data, and eliminates the siloed or outdated records that allow discrepancies to compound across departments.
• Switch from annual stocktakes to cycle counting of inventory: Instead of shutting down for massive annual stock takes, continuously audit smaller subsets of inventory. For example, prioritize high-value items and those with safety stock at risk. By catching discrepancies in rotation, you have a higher chance of correcting errors before they reach fulfillment.
• Use barcoding and RFID tracking and scanning: Automated scanning tracks item movements in real time and removes manual data entry at receiving, putaway, picking, and shipping. This means fewer chances for human error to enter the record.
• Standardize receiving procedures: Verify every incoming shipment at the dock before it enters the system. Receiving is where the chain of inaccuracies usually begins. One discrepancy that slips past the team will follow that stock through every subsequent stage of fulfillment.
• Maintain location accuracy through clear labelling and logical organization: When items are consistently stored in designated, well-marked locations, staff can easily and consistently find, count, and record stock, reducing errors in inventory control processes.

If you’re looking for a faster way to reduce manual-entry errors in receiving, Logiwa’s RF scanning and mobile operations tools can help. As part of our Digital Warehouse solution, which provides warehouses with easy-to-use mobile apps and automation rules, this modern warehouse technology gives teams and managers real-time visibility into every order and every process every day.

How modern technology enhances inventory accuracy

Modern technology can enhance inventory accuracy in several ways. Implementing warehouse management software (WMS) helps you maintain a real-time record of every stock movement. Since the system constantly updates, staff can clearly see discrepancies as they happen rather than spotting them weeks later during a manual count.

Similarly, directed putaway and picking guides staff to specific bin locations so they don’t have to rely on memory or convention. As such, mislabeling and misplacement errors go down.

Introducing automated scanning workflows also eliminates manual data entry at every touchpoint, reducing human error rates. Built-in reporting and discrepancy alerts further reveal gaps between expected and actual stock levels before they reach the fulfillment stage, so managers have the opportunity to investigate and correct errors while the impact is still contained.

Teams looking for these capabilities in a single platform can explore Logiwa’s cloud fulfillment tools.

Close inventory accuracy gaps with the right WMS

Left unaddressed, inventory accuracy gaps can compound quickly, slowing fulfillment and inflating costs. A modern WMS like Logiwa gives teams the tools they need to avoid these issues and stay ahead of the competition. Real-time visibility and control over inventory, RF barcode scanning integrations, directed putaway, forecasting, and reporting surface discrepancies before they reach fulfillment, all in a single platform.

Interested in seeing how Logiwa works? Request a free demo today.

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