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PROB Function

Excel 2007+

Summary

The Excel PROB function calculates the probability that values within a specified range fall between two given limits. It's an essential statistical tool for discrete probability distributions, enabling precise probability calculations for specific value ranges or exact matches.

Syntax

PROB(x_range, prob_range, [lower_limit], [upper_limit])

Parameters

Parameter	Type	Required	Description
x_range	`Range`	Yes	Range of numeric outcome values paired with probabilities
prob_range	`Range`	Yes	Corresponding probability values (0 to 1, sum must equal 1)
lower_limit	`Number`	No	Lower bound for probability range calculation
upper_limit	`Number`	No	Upper bound for probability range (optional)

Using the PROB Function

PROB is designed for analyzing discrete probability distributions where each outcome has a specific probability. Use it to determine the likelihood of events occurring within value boundaries, making it invaluable for decision analysis, risk assessment, and statistical modeling in Excel.

Common PROB Examples

Exact Value Probability

=PROB(A2:A5,B2:B5,2)

Calculates probability that x equals 2 (returns 0.1 for sample data where x=2 has probability 0.1)

Range Probability

=PROB(A2:A5,B2:B5,1,3)

Probability that x falls between 1 and 3 inclusive (returns 0.8 for sample: 0.3+0.1+0.4)

Frequently Asked Questions

PROB returns #NUM! error. All probabilities must form a valid distribution summing exactly to 1.

Yes, omitting upper_limit calculates the probability of x_range exactly equaling lower_limit.

Common Errors and Solutions

#NUM! error

Cause: prob_range contains values ≤0, >1, or sum ≠1

Solution: Ensure all probabilities are between 0-1 and total exactly 1

#N/A error

Cause: x_range and prob_range have different numbers of values

Solution: Match the count of values in both ranges exactly

#VALUE! error

Cause: Non-numeric data in x_range or prob_range

Solution: Verify all cells contain valid numbers

Notes

x_range and prob_range must have identical dimensions
Probabilities are validated: each 0≤p≤1 and Σp=1
Use for discrete distributions only (not continuous)
When upper_limit omitted: P(lower_limit) = exact match probability

Compatibility

Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365

Not available in:

Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+