Inventory turnover is the metric most likely to be quoted with confidence and understood poorly. Someone finds an industry average, notices the company sits below it, and a stock reduction target appears. Occasionally that’s the right conclusion. Frequently the comparison was meaningless from the start.

Calculate it Consistently

Turnover is cost of goods sold divided by average inventory value. Two things commonly go wrong.

Using revenue instead of cost of goods sold inflates the ratio by your gross margin, making comparison with anyone using the correct method meaningless.

Using a single point-in-time inventory value rather than a true average distorts the figure badly in seasonal businesses. Use a monthly average across the period.

Why Cross-company Benchmarks Mislead

Published segment averages should be treated as extremely rough orientation, not targets. The variation within any segment is usually wider than the variation between segments, for reasons that have nothing to do with how well inventory is managed.

Business model dominates. A make-to-order manufacturer with short lead times turns inventory far faster than a make-to-stock manufacturer serving customers who expect immediate availability. Neither is better managed.

Vertical integration matters. A company doing more processing in-house holds more work in progress by definition.

Product characteristics matter. Long-lead components, imported materials, expensive tooling-dependent parts, and regulated materials all require more stock regardless of skill.

And accounting choices differ — valuation method, what sits in cost of goods sold, whether consignment stock appears on your balance sheet or the supplier’s.

Comparisons That Do Work

Your own trend over time, on a consistent calculation. This is by far the most useful version, because everything structural is held constant and movement means something.

Between your own sites or product lines, where the business model is comparable. Differences here are usually real and worth investigating.

Split by category — raw material, work in progress, finished goods — because a blended figure hides where the issue sits and the three respond to completely different interventions. Raw material turns reflect procurement and supplier lead times. Work in progress reflects production flow. Finished goods reflect forecasting and service policy.

What Turnover Doesn’t Tell You

A single ratio hides distribution entirely. A company turning inventory six times could be turning most items twelve times while holding a large block of dead stock that never moves. The average looks acceptable; the reality is two separate problems.

Always look at the distribution alongside the ratio — turns by item, with the slow tail identified. That’s where the actual opportunity is, and it’s invisible in the headline number.

Pair it With Service

Turnover on its own drives one behaviour: reduce stock. Push it far enough and service collapses. Reviewed alongside on-time-in-full, the trade-off stays visible and improvement means something — turning inventory faster at constant service is a real gain, and turning it faster by disappointing customers is not.

ticktick.ai reports turns by category and item with the slow-moving tail broken out, alongside service performance.