How Stockie's inventory forecasting works
Stockie’s inventory forecasting helps you predict when products will need to be reordered — before they run out of stock.
It analyses your recent sales data, lead time, and safety stock to calculate sales velocity, reorder points, and forecasted reorder dates for every product variant.
These forecasts power Smart Mode notifications, along with upcoming features like automated purchase orders.
How Stockie calculates forecasts
Every night, Stockie updates your forecasts using your store’s most recent sales and inventory data.
For each product variant, Stockie calculates the following key metrics:
| Metric | Description |
|---|---|
| Sales velocity | The average number of units sold per day during your chosen look-back period. Days when the product was out of stock are automatically excluded to ensure accuracy — unless your Shopify product is set to Continue selling when out of stock, in which case those sales days are still included. |
| Stockout in | The estimated number of days before available inventory is expected to run out, based on sales velocity. |
| Reorder point | The stock level at which Stockie predicts you should place your next order. Calculated automatically using your lead time and safety stock. |
| Reorder in | The estimated number of days until your available stock is forecasted to reach its reorder point. |
| Suggested reorder qty | The recommended quantity to reorder to ensure you have your configured restock-to days of inventory available immediately after replenishment — in other words, your target maximum days of cover. |
🕒 Forecasts refresh automatically every night at midnight in your store’s timezone, or you can trigger a manual refresh at any time.
Sales velocity (how it’s calculated)
Stockie determines sales velocity by analysing recent sales for each product variant over your selected look-back period (for example, 30, 60, or 90 days).
- Out-of-stock days are excluded so that periods with no inventory don’t artificially lower your average sales rate.
- The only exception is when a product is set to Continue selling when out of stock in Shopify. In that case, those days are still counted since they represent valid back-orders or pre-sales.
💡 Tip: Choosing the right look-back period helps balance stability and responsiveness.
Shorter periods (e.g., 30 days) react faster to recent trends; longer ones (e.g., 90 days) smooth out temporary fluctuations.
Lead time and safety stock
Two key inputs drive accurate reorder point calculations:
- Lead time – how long it takes (in days) for new stock to arrive after placing an order.
- Safety stock – extra buffer inventory expressed in days of cover. Stockie automatically converts this value into units using your product’s sales velocity.
✏️ Reorder point formula:
(Lead time × Sales velocity) + (Safety stock × Sales velocity)
For example:
If your sales velocity is 5 units/day, lead time is 10 days, and safety stock is 4 days,
Reorder point = (10 × 5) + (4 × 5) = 70 units
💡 Tip: Using safety stock in days makes it easier to maintain consistent coverage across products — for example, always keeping an extra 4 days of inventory on hand regardless of sales speed.
👉 Learn how reorder points are automatically calculated →
How forecasts power Smart Mode notifications
Smart Mode notifications use your forecast data to highlight which products need to be reordered soon.
Here’s what happens behind the scenes:
- Stockie calculates each product’s reorder point and reorder in value (how many days until it hits that point).
- Your notification’s window (e.g., 7 days) defines how far ahead to look.
- Any product whose reorder date falls within that window is included in your Smart Mode notification.
- Products appear alongside their forecasted Reorder in and Suggested reorder qty metrics for quick decision-making.
💡 Tip: Shorter notification windows (3–7 days) surface only the most urgent products; longer windows (14–30 days) give more notice for planning.
👉 Learn how to create a notification (Smart Mode) →
Factors that affect forecast accuracy
Forecast accuracy depends on the quality and stability of your data.
- Sales history: Products with steady sales patterns generate more reliable velocity averages.
- Inventory history: Days with zero stock are automatically excluded (unless “Continue selling when out of stock” is enabled).
- Lead time & safety stock: Keep these updated — inaccurate values can shift your reorder points significantly.
Seasonality: Changes in buying patterns (for example, holidays or seasonal peaks) can impact forecast accuracy.
Handling seasonality adjustments is planned for a future update to Stockie’s forecasting engine.
💡 Tip: You can review or adjust lead time and safety stock anytime under Forecasting → Manage settings.
Example: how it all comes together
Let’s say you sell a product with:
- Sales velocity: 4 units/day
- Lead time: 7 days
- Safety stock: 4 days
- Current available stock: 60 units
- Restock-to days of inventory: 30 days
Stockie calculates:
- Reorder point: (7 × 4) + (4 × 4) = 44 units
- Reorder in: (60 − 44) ÷ 4 = 4 days (about 4 days until reorder point)
- Stockout in: 60 ÷ 4 = 15 days (expected to run out in 15 days)
Suggested reorder qty: (30 × 4) + (7 × 4) − 60 = 68 units
→ You should reorder 68 units so that once the new stock arrives after 7 days, your available inventory returns to your target 30 days of cover.
If your Smart Mode notification window is set to 7 days, this product will appear in your next notification — since it’s forecasted to reach its reorder point within the next 4 days.
💡 Tip: The suggested reorder quantity always accounts for the sales expected during your supplier’s lead time — ensuring you hit your restock-to target when the new order arrives.