First month of Pro is free for early-access sign-ups. Use code FREEMONTH 🎉

Get started
Inventory

Inventory runway

Days of stock

How many days your current stock will last at your real sales pace.

Inventory runway is units in stock divided by your daily sales rate — how long the stock lasts before you run out. Watching it (adjusted for growth) lets you reorder before a stockout, not after. Run out of a bestseller and you lose the sales and your hard-won rank.

Formula

Days of stock = Units in stock ÷ adjusted daily sales

Example: 3,800 units ÷ 22/day = ~173 days of stock.

What a good result depends on

Enough to comfortably cover your lead time plus a safety buffer.

Common mistakes

  • Using flat average sales when demand is growing or seasonal.
  • Ignoring that lead times stretch around peak seasons.
Free calculator
Inventory Runway Calculator
Calculate it
Ask the Captain

Which products will run out of stock in the next 30 days?

Monitor it live