Inventory glossary

What is Available to promise?

Available to promise is the quantity of a product you can still sell right now, after subtracting orders already committed against your current stock and before counting stock that has not arrived yet.

Available to promise tells you the real number you can sell today, not just what is sitting on the shelf. For a small Shopify store, this matters most during sales, restocks, or when a product is close to selling out, because it keeps your storefront honest about what you can actually ship.

Use it as a quick check before you advertise a product heavily or let a wholesale customer place a large order. If available to promise is low, you either need to slow down marketing on that item or get a purchase order moving before you run out.

Formula

Available to promise = On hand inventory - Committed inventory

Example

A candle shop has 80 units of a jar candle on hand. 25 units are already committed to unshipped orders. Available to promise is 80 - 25 = 55 units. If a new order comes in for 10 units, ATP drops to 45.

Common mistakes

  • Confusing available to promise with on hand inventory and promising stock that is already committed to other orders.
  • Forgetting to subtract backorders or pre-orders from the available count.
  • Not updating ATP in real time during flash sales, which leads to overselling.

Available to promise and SteadyShelf

SteadyShelf does not track available to promise directly, but its sales forecasts and reorder dates are built from the stock levels Shopify reports, so a store with tight ATP will show up as needing a purchase order sooner.

SteadyShelf is launching on the Shopify App Store. Join early access to get the install link first.

Related terms

Committed inventory · On hand inventory · Overselling · Allocated inventory · Backorder

Full inventory glossary

FAQ

Is available to promise the same as on hand inventory?

No. On hand inventory is what is physically in the warehouse right now. Available to promise is what is left to sell after you subtract orders already placed against that stock. ATP is usually lower than on hand once customers start buying.

Why does available to promise matter for small stores running sales?

Yes, if more customers order than you have ATP for, you oversell. The product page shows in stock but you cannot fulfill every order. Checking ATP before running a sale or promotion helps you avoid this.

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