Reorder Point Calculator
Find the stock level that should trigger your next purchase order, built from how fast you sell and how much your lead time actually varies.
Your numbers
Your result · updates as you type
Reorder point
288 units
Reorder when stock falls to 288 units. That's 120 units for average usage during the lead time, plus 168 units of safety stock for a slower delivery or a busier stretch.
- Safety stock built in
- 168 units
- Days of average sales this covers
- 24 days
- If lead time never varied
- 120 units
Shopify's base admin doesn't have a native reorder-point field: use this number as the trigger for a Shopify Flow low-stock workflow, or enter it in an inventory app. In WooCommerce, set it as the product's low stock threshold under Product data → Inventory, or globally at WooCommerce → Settings → Products → Inventory.
Breakdown
- Average usage during average lead time
- 12 × 10 = 120 units
- Maximum usage during maximum lead time
- 18 × 16 = 288 units
- Safety stock (the difference)
- 168 units
- Reorder point
- 288 units
Why a simple average isn't enough
A reorder point based only on average daily usage and average lead time works fine until a supplier is slow or a product has a busy week. This calculator builds in a cushion by comparing your worst realistic case against your average case.
Example: the default numbers
- Average daily usage × average lead time
- 12 × 10 = 120 units
- Maximum daily usage × maximum lead time
- 18 × 16 = 288 units
- Safety stock (the difference)
- 288 − 120 = 168 units
Reorder point = 120 + 168 = 288 units. Reorder when stock falls to 288 units, which covers 24 days of average sales.
Using the number on Shopify or WooCommerce
- 01
Shopify
Shopify's base admin doesn't have a built-in reorder-point field. Use this number as the trigger condition in a Shopify Flow workflow ("inventory quantity is less than or equal to X"), or enter it into a dedicated inventory app.
- 02
WooCommerce
Set it as the product's own Low stock threshold on the Inventory tab of the product, or set a global default at WooCommerce → Settings → Products → Inventory.
Keeping it accurate
- Recalculate seasonally. A reorder point set from summer sales will trigger far too late in November.
- Use a real maximum, not a freak outlier. One viral day or one lost shipment shouldn't set your baseline; use a typical bad week or a typical slow supplier run.
- Prefer the statistical method for critical SKUs. For a product where a stockout really hurts, use the safety stock calculator, which targets a specific in-stock probability instead of a fixed worst case.
Questions people ask
What is a reorder point?
The stock level at which you should place your next purchase order, so the new stock arrives before you run out.
How is a reorder point different from safety stock?
Safety stock is the buffer on top of expected usage during lead time. The reorder point is the full trigger level: expected usage during lead time plus safety stock.
What if my lead time barely varies?
Set maximum lead time close to average lead time. Safety stock will shrink toward zero, and the reorder point will track average usage during lead time.
Does this account for seasonality?
Not directly. Update the daily usage figures for the season you're heading into, since a summer average will understate a November reorder point.
Related tools
Want this builtinto your store?
I'm Emmanuel, a Shopify and WooCommerce developer. If this tool pointed at something you'd rather have fixed for you (a faster store, cleaner product data, a migration, a custom feature), send me a note.
Emmanuel Asika
Shopify & WooCommerce developer, Dublin
I build and fix online stores: new builds, migrations, speed, SEO and the custom bits apps can't do.
Last reviewed 30 September 2026.
Sources: Shopify Help Center: Inventory notifications · WooCommerce docs: Products settings (inventory)