Free · Logistics calculators 🚚

Inventory Reorder Level from Days of Cover

Calculate a stock reorder level from replenishment lead time, base-cover days, safety-cover days and a steady sales rate.

  • Formula & worked example
  • Private in your browser
  • No signup
Go to tool

Calculator inputs

Loading calculator…

How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

At 10 items per day, a 5-day lead time plus 2 base-cover days and 3 safety-cover days give a reorder level of 100 items.

Reorder level = (lead time + base-cover duration + safety-cover duration) × sales per unit time

Worked example

Enter these known values and leave the other values blank.

Base stock cover duration
2 days
Safety stock cover duration
3 days
Replenishment lead time
5 days
Average sales rate
10 / days
Modeled reorder level
100 items

Assumptions and limitations

  • Base stock and safety stock are durations of demand cover in this model, not item quantities. Their selected units are converted to a common time basis.
  • The sales rate is assumed steady and positive. Lead, base-cover and safety-cover durations may be zero.
  • This deterministic threshold does not estimate forecast error, demand variability, service level, supplier reliability or an optimal order quantity.
  • The result can be fractional. For indivisible items, apply an explicit inventory rounding policy; the calculator does not silently round the threshold up.

Common questions

Should I enter safety stock as days or items?

Enter a duration of demand cover. For example, 30 safety-stock items at 10 items per day correspond to three days in this model.

Is the reorder level the quantity I should order?

No. It is a modeled stock threshold for considering replenishment. The order quantity requires a separate policy or model.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

Explore logistics calculators 🚚 or browse all everyday life calculators.