Safety stock

The calculator uses the numbers you enter. With 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit the result is 52 u | $419.09. This is not an SAP MRP run.

This is not an SAP MRP run. Inventory carrying cost is on Inventory carrying cost.

Input data

Parametry modelu
Scenariusz dodatkowy

Results

Enter data and click Calculate.

How it works

Safety stock in this calculator is Z × σ × √lead time, then the value. With 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit the result is 52 u | $419.09.

ss = Z × σ × √LT. value = ss × unit cost. You type Z. The calculator does not read a norm table. The formula uses Z-score and lead time.

52 u | $419.09 is not an SAP MRP run. Another set of numbers gives 23 u | $137.38, and a further set gives 112 u | $1,338.78. Empty scenario fields do not change the result.

Inventory carrying cost answers a different question. Buffer days does too. Here 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit leave 52 u | $419.09.

Type 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit and click Calculate. Two more ready sets sit under the form: 23 u | $137.38 and 112 u | $1,338.78.

Other numbers on the same labels move the result. The first example gives 52 u | $419.09.

Formula

ss = Z × σ × √LT. value = ss × unit cost. You type Z. The calculator does not read a norm table.

How to use

  1. Type 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit.
  2. Leave the scenario fields empty if you do not have those numbers.
  3. Click Calculate. This set shows 52 u | $419.09.
  4. The second example under the result is 23 u | $137.38, the third 112 u | $1,338.78.
  5. This is not an SAP MRP run.

Safety stock = 52 u | $419.09

With 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit the result is 52 u | $419.09. This is not an SAP MRP run.

Safety stock
Safety stock is this calculator's result. The first example is 52 u | $419.09.
Z-score
The formula includes Z-score. The second example gives 23 u | $137.38.
lead time
The formula includes lead time. The second example gives 23 u | $137.38.

Examples

Example 1

  • 40 demand/day
  • 12 σ
  • 7 LT days
  • 1.65 Z
  • 8 USD/unit

52 u | $419.09

With 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit the result is 52 u | $419.09. This is not an SAP MRP run.

Example 2

  • 25 demand/day
  • 8 σ
  • 5 LT days
  • 1.28 Z
  • 6 USD/unit

23 u | $137.38

With 25 demand/day, 8 σ, 5 LT days, 1.28 Z, 6 USD/unit the result is 23 u | $137.38.

Example 3

  • 60 demand/day
  • 18 σ
  • 10 LT days
  • 1.96 Z
  • 12 USD/unit

112 u | $1,338.78

With 60 demand/day, 18 σ, 10 LT days, 1.96 Z, 12 USD/unit the result is 112 u | $1,338.78.

Related calculators

Inventory carrying cost

Inventory carrying cost: annual = stock × (capital+warehouse+markdown+insurance)/100.

Use calculator →

Buffer days

Buffer days: day delta × daily usage × carry vs stockout risk.

Use calculator →

All agentic commerce calculators

Common questions

What do you get from 40 demand/day, 12 σ, 7 LT days, 1.65 Z, 8 USD/unit?

52 u | $419.09. This is not an SAP MRP run.

What about the second example?

23 u | $137.38.

What about the third example?

112 u | $1,338.78.

Is 52 u | $419.09 an SAP MRP run?

No. It is the result from the numbers you enter.

Do empty fields change 52 u | $419.09?

No. Empty scenario fields do not change the result.

How is this different from Inventory carrying cost?

That calculator answers another question. Here Safety stock stays at 52 u | $419.09.

Does a comma in the number work?

Yes. A comma and a dot mean the same in a number field.

Why is there a currency in 52 u | $419.09?

The header label is usually USD. Another currency changes the label, not the amount.

Do 25 demand/day, 8 σ, 5 LT days, 1.28 Z, 6 USD/unit give 23 u | $137.38?

Yes. That is the second example under the form.

Knowledge sources

Agent cost is a sketch from your rates. Below are EU, OECD and NIST AI frames, not a contract quote.

Page updated in 2026.