How to Calculate a Range Probability with PROB in Excel

Use PROB to add up probabilities from your own demand table — for one value, a range, or a sell-out.

You will learn to

• Find the probability of one exact value
• Find the probability of a range of values
• Find the chance demand exceeds stock

How it works

PROB works with your own probability table rather than a textbook distribution. Give it the possible values, their probabilities and a lower limit, and it returns the probability of that exact value; add an upper limit and it adds up every probability in that range.

The probabilities must add up to exactly 1, or PROB returns #NUM!. It is ideal for demand tables built from history — "on 25% of days we sell 3 cakes" — and for questions like "how often will we sell out?"

=PROB(A2:A8,B2:B8,2,4)