This article describes the formula syntax and usage of the PROB function (function: A prewritten formula that takes a value or values, performs an operation, and returns a value or values. Use functions to simplify and shorten formulas on a worksheet, especially those that perform lengthy or complex calculations.) in Microsoft Excel.
Description
Returns the probability that values in a range are between two limits. If upper_limit is not supplied, returns the probability that values in x_range are equal to lower_limit.
Syntax
PROB(x_range, prob_range, [lower_limit], [upper_limit])
The PROB function syntax has the following arguments (argument: A value that provides information to an action, an event, a method, a property, a function, or a procedure.):
 X_range Required. The range of numeric values of x with which there are associated probabilities.
 Prob_range Required. A set of probabilities associated with values in x_range.
 Lower_limit Optional. The lower bound on the value for which you want a probability.
 Upper_limit Optional. The optional upper bound on the value for which you want a probability.
Remarks
 If any value in prob_range ≤ 0 or if any value in prob_range > 1, PROB returns the #NUM! error value.
 If the sum of the values in prob_range is not equal to 1, PROB returns the #NUM! error value.
 If upper_limit is omitted, PROB returns the probability of being equal to lower_limit.
 If x_range and prob_range contain a different number of data points, PROB returns the #N/A error value.
Example
The example may be easier to understand if you copy it to a blank worksheet.
How do I copy an example?
 Select the example in this article. If you are copying the example in Excel Online, copy and paste one cell at a time.
Important: Do not select the row or column headers.
Selecting an example from Help
 Press CTRL+C.
 Create a blank workbook or worksheet.
 In the worksheet, select cell A1, and press CTRL+V. If you are working in Excel Online, repeat copying and pasting for each cell in the example.
Important: For the example to work properly, you must paste it into cell A1 of the worksheet.
 To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
After you copy the example to a blank worksheet, you can adapt it to suit your needs.

A 
B 
x 
Probability 
0 
0.2 
1 
0.3 
2 
0.1 
3 
0.4 
Formula 
Description (Result) 
=PROB(A2:A5,B2:B5,2) 
Probability that x is 2 (0.1) 
=PROB(A2:A5,B2:B5,1,3) 
Probability that x is between 1 and 3 (0.8) 
