When to reorder so you don't stock out, given lead time and daily sales. Critical for dropshippers with private-label stock.
All calculations run in your browser. Nothing is sent to a server. Last updated: 2026-07-19 · Formula verified against published sources (see below).
Tells you when to reorder stock so you don't run out before the next shipment arrives. Critical for dropshippers who hold private-label stock or bestselling products — running out of stock kills ad momentum and conversion rate.
Lead time demand = average daily sales × lead time in days
Reorder point = lead time demand + safety stock
Safety stock is your buffer for variance — both in demand (a sudden 3× sales spike from a viral ad) and in supply (supplier shipping takes 21 days instead of 14). A reasonable rule: 50–100% of lead time demand for new products (where variance is high), 25–50% for stable products.
If you set safety stock too low, you'll stock out during demand spikes. Too high, you'll tie up capital in slow-moving inventory. There's no perfect number — adjust based on actual stockout history.
| Input | Value |
|---|---|
| Average daily sales | 5 units |
| Supplier lead time | 14 days |
| Safety stock | 10 units |
| Lead time demand | 70 units |
| Reorder point | 80 units |
| Days of cover at reorder | 16 days |
When your stock drops to 80 units, place the next order. By the time the order arrives (14 days later), you'll have sold 70 units, leaving you at 10 (your safety stock) — exactly the buffer you wanted.
How many times your inventory sells out and replenishes in a period. Higher is better — until you stock out.
How many units you need to sell to cover fixed costs (Shopify plan, apps, ad budget). The line between red and black.
Project monthly cash flow from sales, costs, ad spend, and payment-processor payout lag. Find the gap before it finds you.
Even dropshippers hold some inventory — samples, private-label stock, bestsellers. Here's how to size it without overcommitting cash.