How to Investigate Inventory Discrepancies: A Step-by-Step Guide

Your system says you have 47 units. You counted 42. Now what?

An inventory discrepancy is the mismatch between what your records say you should have and what you actually counted. For small business owners, these happen more often than they should — and most of the time, the root cause is fixable.

Here's how to find out what went wrong.

Step 1: Document the Discrepancy (Right Now)

Don't wait. The moment you notice a mismatch between your system count and your physical count, record it:

• What item? Be specific. Not "general merchandise" — the exact SKU.
• System count? What your inventory system shows.
• Physical count? What you actually counted.
• Difference? Over or under? By how much?
• When was it last accurate? When was the last time this item reconciled?

This takes 2 minutes. It saves hours of investigation later.

Step 2: Check the Last Three Transactions

Pull your transaction log for this item and look at the last 3 movements:

• Incoming stock: Did you receive what you think you received? Check against the PO and the receiving scan.
• Outgoing stock: Were all sales/transfers logged? Sometimes items walk out but don't get scanned.
• Returns or adjustments: Were damaged items written off? Were customer returns processed?

A missing scan in any of these is usually your culprit.

Step 3: Physical Recount (Different Person, Different Method)

Your first count might have been wrong. Have someone else count the same item using a different method:

• If you counted by hand, use a barcode scanner next time.
• If you scanned, hand-count to verify.
• Use a second person as a witness.

If the recount matches your system, human error was the issue. If it matches your first count, your system data is the problem.

Step 4: Interview Your Team

If the discrepancy persists:

• Who handled this item last? Talk to them. Ask what they remember.
• Were there any unusual events? A rush, a delivery mix-up, a return that wasn't logged?
• Has anyone mentioned damage or theft? Sometimes these aren't formally reported.

Most discrepancies are human error, not theft. A quick conversation usually uncovers the answer.

Step 5: Decide on a Correction

Once you know what happened, you have two choices:

• Adjust your system to match reality. If your physical count is accurate and your system is wrong, update the system. This is the safe choice for most small businesses.
• Investigate further. If you suspect theft or a systematic problem, dig deeper before adjusting. Don't just sweep it under the rug.

Make the adjustment, log it with the reason (e.g., "Physical recount 6/4/26 — damage discovered during receiving"), and move forward.

The Real Root Causes

After investigating hundreds of discrepancies across multiple locations, here's what actually causes them:

• Receiving errors (40%) — Item counts wrong on arrival. You didn't catch it at the dock.
• Unlogged sales (25%) — Item was sold or transferred but the transaction wasn't scanned or entered.
• Damage during handling (20%) — Item broke or spoiled. Wasn't marked as damaged or written off.
• Manual counting errors (10%) — You miscounted, or inventory was restocked between your count cycles.
• Theft (5%) — Real, but surprisingly rare in most small businesses if you're counting weekly.

Once you know which bucket your problem falls into, you can prevent it next time.

Prevention: The Weekly Count Method

The best way to keep discrepancies small is to count frequently. A weekly 30-minute inventory count across all items catches problems before they snowball. When you find a discrepancy on a weekly basis:

• It's only off by a small amount (usually 1-5 units, not 500).
• You remember exactly what happened last week.
• Your team is still there to explain it.
• You can fix it immediately.

This is why the weekly count — even though it takes time — is the fastest way to stay accurate long-term.

Summary

When you find a discrepancy:

1. Document it immediately.
2. Check your last three transactions.
3. Recount with a different method.
4. Ask your team what happened.
5. Adjust your system and log the reason.
6. Do it again next week to catch the next one early.

Small discrepancies caught early stay small. It's the ones you ignore that become big problems.