One labelled outcome from an interval
The rule is an inclusive integer interval. For endpoints a and b, there are b - a + 1 possible labels, and each receives probability 1 / (b - a + 1). With 1 and 100, the sample space has 100 values. A draw of 42 is not evidence that 42 was due; it is simply one equally available label.
Worked case: a numbered door prize
Imagine 37 valid entry cards numbered 201 through 237. The range contains 237 - 201 + 1 = 37 cards. If the display returns 219, that card wins and its chance before the draw was 1/37, about 2.70%. The calculation is only fair when every number in the interval is attached to exactly one eligible card.
Why endpoints matter
A common mistake is to count by subtraction alone. The labels 201, 202, and 203 make a three-item range, not two, because both ends are included. Likewise, a missing ticket number or a duplicated printed label changes the real population even when the screen still shows a neat numerical interval.
When one draw is the wrong rule
This page makes one independent selection. It does not remember a winner, prevent a later repeat, rank entrants, or prove that a public drawing followed a published procedure. A multi-prize raffle needs an exclusion list or a shuffled ticket set after each award; eligibility and record keeping remain responsibilities of the organizer.
Audit the population before pressing draw
List the physical card, applicant, or record represented by every label. If card 214 was voided, leaving it in a 201–237 range gives a nonexistent entrant a chance and changes everyone else's probability. A short public record of the range and the selected label makes a simple draw easier to explain later.
Questions about this selection rule
Why can the minimum appear?
The first endpoint is a valid outcome, just like every interior integer.
Can it return a negative number?
This form is configured for non-negative bounds; use a method that explicitly supports signed values when labels below zero matter.
Does one result predict the next?
No. A fresh draw does not make nearby or previously absent numbers more likely.
Other number formats
All number generators · Random PIN Generator · Random Integer Range