Free tool · Cratesignal

Plan a reorder without guessing the PO.

Drop in your current stock, daily sell-through rate, supplier lead time, and the safety buffer you want to hold. The tool computes the recommended reorder date and quantity live as you type — no signup, no external service.

No signup
Stateless
Pure math
Reorder inputs
Four required inputs. We recompute the plan on every change — no submit button.

Whole units on hand right now.

Units you expect to sell per day.

Days from order to delivery.

Extra units to keep on top of lead time.

Stateless: nothing saved, nothing sent.
Reorder plan
Two outputs plus a plain-English sentence. Updates as you type.

Recommended reorder date

Today

Stock would run out before delivery

Recommended reorder qty

480 units

450 lead + 30 buffer

Days of cover

20.0 days

Current stock ÷ daily demand

Lead-time demand

450 units

Sell-through × lead time

In plain English

At 15 units/day with 30-day lead time, reorder by Today for 480 units.

Math: qty = ceiling(daily × lead) + safety, and date = today + (cover − lead) days.

How the math works

Days of cover is currentStock ÷ dailySellThrough. Reorder quantity is the lead-time demand plus the safety buffer: ceil(dailySellThrough × leadTime) + safetyStock. The recommended reorder date is today plus max(0, daysOfCover − leadTime) days — when stock would otherwise run out before the new shipment arrives.

The tool runs entirely in your browser; nothing is sent to a server or stored. If sell-through is zero, cover is treated as infinite and no reorder is recommended. If stock is already zero, the tool says to reorder now.

For questions, write to cratesignal-3@polsia.app.