COMBIN
Returns the number of combinations for a given number of items. Calculates how many ways you can choose k items from n items, regardless of order.
COMBIN(number, number_chosen)Arguments
numberTotal number of items (n)number_chosenNumber of items to choose (k)
=COMBIN(6, 2)15 ways to choose 2 items from 6
=COMBIN(49, 6)Possible combinations in a 6/49 lottery
=COMBIN(10, 3)120 ways to pick a team of 3 from 10 people
- •Order does not matter (unlike PERMUT)
- •COMBIN(n,k) = n! / (k! * (n-k)!)
- •Both arguments must be non-negative integers
- •Confusing COMBIN with PERMUT - COMBIN counts combinations where order doesn't matter, while PERMUT counts permutations where order does matter, and picking the wrong one for a specific counting problem gives a very different (and usually much larger) result
- •Passing a number_chosen argument larger than number, which raises a #NUM! error since you can't choose more items than are available
- •Passing negative numbers or forgetting that both arguments are truncated to integers first, which can produce unexpected results if decimal values were intended to matter
PERMUTCounts permutations where order matters, a related but distinct counting problem from COMBIN's order-independent combinations.COMBINACounts combinations that allow repetition, relaxing COMBIN's assumption that each item can only be chosen once.FACTUsed internally in the mathematical formula behind COMBIN, since combinations are calculated using factorials.What's the difference between COMBIN and PERMUT?
COMBIN counts groupings where the order of selection doesn't matter (like choosing a committee), while PERMUT counts arrangements where order does matter (like ranking finishers in a race). PERMUT always returns a result equal to or larger than COMBIN for the same inputs.
Why does COMBIN return a #NUM! error?
You're likely asking to choose more items (number_chosen) than are actually available (number) - you can't choose 5 items from a set of 3.
Does COMBIN allow choosing the same item more than once?
No, standard COMBIN assumes each item can only be chosen once. Use COMBINA instead if repetition should be allowed.
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