Beginner 6 min readKotlin 2.0
Kotlin Ranges — .. , until, downTo, and step
Ranges represent a sequence of values between two endpoints. Kotlin ranges work with numbers, characters, and many collection operations.
What You Will Learn
- Inclusive range with ..
- Exclusive range with until
- Reverse range with downTo
- Step values
- Check membership with in
- Character ranges
Inclusive Range with ..
1..5 creates a range from 1 to 5, including both endpoints.
Inclusive Range
kotlin
fun main() {
val range = 1..5
for (n in range) print("$n ")
println()
println(3 in range) // containment check
println(6 in range)
}Output
1 2 3 4 5
true
false
1..5 includes 1, 2, 3, 4, 5. The in operator checks if a value is within the range.
Exclusive Range with until
1 until 5 creates a range from 1 to 4 (5 excluded).
until Range
kotlin
fun main() {
for (i in 0 until 5) print("$i ")
println()
// Equivalent using indices
val list = listOf("a","b","c")
for (i in 0 until list.size) print("${list[i]} ")
}Output
0 1 2 3 4
a b c
until is useful for list indices: 0 until list.size gives valid indices without going out of bounds.
downTo and step
downTo creates a descending range. step controls the increment.
downTo and step
kotlin
fun main() {
for (i in 10 downTo 1 step 3) print("$i ")
println()
for (c in 'a'..'e') print("$c ")
}Output
10 7 4 1
a b c d e
10 downTo 1 step 3 counts down: 10, 7, 4, 1. Character ranges work the same as number ranges.
Practice Exercise
Exercisepredict output
What prints? for (i in 1..10 step 3) print("$i ")
Quick Quiz
Quick Quiz
What is the difference between 1..5 and 1 until 5?
Frequently Asked Questions
Related Tutorials
Last updated: 2026-05-01Kotlin 2.0
Written by KotlinGuide Editorial Team · Reviewed by KotlinGuide Technical Review