Random Number Range Calculator

Enter a minimum and maximum value to instantly see the count of integers in that range, the midpoint, the total spread, and the probability of selecting any single value at random. When working with random number generators, dice rolls, lottery pools, or statistical sampling frames, knowing how many integers fall within a range — and how likely any specific one is — helps you design fair experiments, set correct bounds, and reason clearly about probability. Both the minimum and maximum values are included in the count, which is why the formula adds 1 to the difference. Adjust either bound to see the count and probabilities update instantly. Understanding range size is fundamental to simulation design, game balancing, and any situation where discrete uniform distributions govern outcomes. Whether you are setting the bounds for a random loot table, defining a scoring window, or sizing a sample space for a statistics problem, this tool gives you the key numbers at a glance.

The total count of integers within the range is calculated as max − min + 1, because both endpoints are included — for example, 1 to 6 contains 6 values: 1, 2, 3, 4, 5, and 6. The spread is simply max − min, representing the distance from one endpoint to the other. The midpoint is (min + max) / 2, which is the arithmetic center of the range; it will be a whole number only when the count is odd, and a half-integer when the count is even. The probability that a uniformly randomly chosen integer lands on any specific value is 1 ÷ count × 100. This assumes a discrete uniform distribution where every integer in the range is equally likely — the assumption behind a fair dice roll, lottery draw, or random number generator with integer output.