Is string interpolation in Kotlin the same as string concatenation?

They produce the same result but string templates are safer and more readable. Kotlin compiles string templates to efficient StringBuilder operations internally.

When must I use ${} instead of $ in a template?

Use $name for simple variable names. Use ${expression} when you need a property, function call, or arithmetic: "${user.name}" or "${a + b}".

Beginner 6 min readKotlin 2.0

Kotlin String Templates — $ and ${} Explained

String templates are Kotlin's way to embed values inside strings without concatenation. They make string formatting clean and readable.

What You Will Learn

Use $ to embed variables
Use ${} to embed expressions
Escape $ with a backslash
Use string templates in multi-line strings

Basic String Templates with $

Put $ before a variable name to embed its value inside a string.

Variable in String Template

kotlin
fun main() {
    val name = "Kotlin"
    val version = 2
    println("Learning $name version $version")
    println("$name is awesome!")
}

Output

Learning Kotlin version 2 Kotlin is awesome!

The $ prefix inserts the value of the variable at that position. No concatenation needed.

Beginner Tip: If the variable name is immediately followed by a letter or digit that could be part of the name, use ${} to make the boundary clear: "${name}Guide".

Expressions with ${}

Use ${} to embed any Kotlin expression — not just variable names.

Expressions in String Templates

kotlin
fun main() {
    val a = 10
    val b = 3
    println("$a + $b = ${a + b}")
    println("$a * $b = ${a * b}")
    println("Uppercase: ${"kotlin".uppercase()}")
    println("Name length: ${"Juned".length}")
}

Output

10 + 3 = 13 10 * 3 = 30 Uppercase: KOTLIN Name length: 5

${a + b} evaluates the expression and inserts the result. Any valid Kotlin expression can go inside ${}.

Escaping the $ Sign

To print a literal $ inside a string, use a backslash before it.

Printing a Dollar Sign

kotlin
fun main() {
    val price = 99
    println("Price: \$$price")
    println("Save \$10 today!")
}

Output

Price: $99 Save $10 today!

\$ prints a literal dollar sign. $price inserts the variable value after the literal dollar sign.

Practice Exercise

Exercisepredict output

What does this print? val x = 4 val y = 5 println("${x * y} = $x * $y")

Quick Quiz

When do you use ${} instead of $ in a string template?

Kotlin String Templates — $ and ${} Explained

What You Will Learn

Basic String Templates with $

Variable in String Template

Expressions with ${}

Expressions in String Templates

Escaping the $ Sign

Printing a Dollar Sign

Practice Exercise

Quick Quiz

Frequently Asked Questions

Related Tutorials