Conditional Statements in Dart

By Syncfusion®, Inc. · Last updated November 11, 2026

How a program makes decisions with if, else, else if, nested conditions, switch statements and switch expressions.

What Is a Conditional Statement?

Conditional statement = code that runs only when a condition is true.

Condition = a question with a true or false answer, like marks >= 35.

For example:

• if it rains, take an umbrella
• if marks are 35 or more, print "Pass", else print "Fail"
• if today is Sunday, the school is closed

Conditional statements let a program make decisions.

Simple lesson: a conditional statement asks a question, and runs different code for different answers.

A Real-World Example

Your school's report card app gives a grade for every student.

• 90 or more is Grade A.
• 75 or more is Grade B.
• 35 or more is Grade C.
• Anything less is Try again.

The app runs the same code for every student, but each student can get a different grade. That is a decision chain, and you will build it in this lesson.

What You Will Learn

In this lesson, you will learn:

1. How conditions work, with &&, || and !.
2. The if, if else and else if statements.
3. Nested conditions.
4. switch statements and switch expressions.
5. When to use each kind of decision.

Conditional Fundamentals

Evaluating Conditions

Every condition becomes true or false. Dart works it out using the operators from Operators.

• Single condition: marks >= 35
• Both must be true (&&): age >= 18 && hasVoterId
• At least one (||): isSunday || isHoliday
• The opposite (!): !isAbsent

Conditions become true or false

void main() {
  var marks = 82;
  var isSunday = false;
  var isHoliday = true;
  var isAbsent = false;

  print(marks >= 35);
  print(marks >= 35 && marks < 90);
  print(isSunday || isHoliday);
  print(!isAbsent);
}

Using Conditions Effectively

• Name bool variables like questions: isHoliday, hasPaidFees.
• Write if (isHoliday), not if (isHoliday == true).
• Store a long condition in a variable first, to make it easy to read.

Simple lesson: every decision starts with a condition that is either true or false.

if Statement

if = run a block only when the condition is true.

if (condition) {
  // runs only when condition is true
}

A hot day warning

void main() {
  var temperature = 38;
  if (temperature > 35) {
    print('It is very hot. Drink water!');
  }
  print('Have a good day.');
}

• The condition goes inside ( ).
• The code to run goes inside { }.
• When the condition is false, Dart skips the block and carries on.

Change 38 to 30 and run again. Only the last line prints.

Simple lesson: if runs a block only when its condition is true.

if else Statement

if else = one block when the condition is true, another block when it is false.

Pass or fail

void main() {
  var marks = 28;
  if (marks >= 35) {
    print('Pass');
  } else {
    print('Fail. Better luck next time!');
  }
}

Alternative execution path = a second way through the code. else gives exactly one.

Combining Multiple Conditions

Can this person vote?

void main() {
  var age = 19;
  var hasVoterId = true;
  if (age >= 18 && hasVoterId) {
    print('You can vote.');
  } else {
    print('You cannot vote yet.');
  }
}

if vs if else

• if alone: something extra may happen, or nothing happens.
• if else: exactly one of two things always happens.

Simple lesson: if else always runs one of its two blocks, never both and never none.

else if Statement

else if = check another condition when the ones before it were false.

Decision chain = a chain of if, else if and else that picks one path.

Move the slider and watch which block runs:

Look at two things:

• Dart checks from the top, one condition at a time.
• It stops at the first true one. The rest are skipped, even if they are also true.

Grades from marks you type

import 'dart:io';

void main() {
  print('Enter marks:');
  var marks = int.tryParse(stdin.readLineSync() ?? '') ?? 0;
  if (marks >= 90) {
    print('Grade A');
  } else if (marks >= 75) {
    print('Grade B');
  } else if (marks >= 35) {
    print('Grade C');
  } else {
    print('Try again');
  }
}

Change the Input to 95, then 40, then 10.

Condition Evaluation Order

The order matters. Here the checks are in the wrong order:

A bug: the conditions are in the wrong order

void main() {
  var marks = 95;
  if (marks >= 35) {
    print('Grade C');
  } else if (marks >= 75) {
    print('Grade B');
  } else if (marks >= 90) {
    print('Grade A');
  }
}

A score of 95 gets Grade C, because 95 >= 35 is checked first and is true.

Fix: put the strictest condition first.

Simple lesson: an else if chain runs only the first true block, so order the checks from strictest to loosest.

Nested Conditions

Nested condition = an if inside another if.

Use it when a second question only makes sense after the first answer.

Multi-Level Decision Making

• Outer if: the first and most important check.
• Inner if: only asked when the outer check passed.
• Keep it shallow. More than two levels is hard to read. Use && or else if instead where you can.

Simple lesson: nest an if only when the inner question depends on the outer answer.

Switch Statements

switch = compare one value against a list of possible values, and run the matching case.

What happens on each day?

void main() {
  var day = 'Wednesday';
  switch (day) {
    case 'Monday':
      print('Maths test');
    case 'Wednesday':
      print('Sports period');
    case 'Friday':
      print('Library visit');
    default:
      print('Regular classes');
  }
}

The Parts of a switch

• switch (day) = the value to check.
• case 'Monday': = a case label. If day equals 'Monday', its code runs.
• default: = runs when no case matches. It is like a final else.

Multiple Cases

Write cases one after another, with no code between them, to share one block:

Two days share one block

void main() {
  var day = 'Sunday';
  switch (day) {
    case 'Saturday':
    case 'Sunday':
      print('Holiday!');
    default:
      print('School day');
  }
}

The break Statement

• In Dart 3, a case stops by itself when its code ends. You do not need break.
• You may still see break; at the end of a case in older code. It does the same thing.
• In many other languages, forgetting break runs the next case too. Dart does not do that.

Simple lesson: switch picks the matching case, and default handles everything else.

Switch Expressions

Switch expression = a switch that gives back a value, written with =>.

A grade with a switch expression

void main() {
  var marks = 78;
  var grade = switch (marks) {
    >= 90 => 'A',
    >= 75 => 'B',
    >= 35 => 'C',
    _ => 'Try again',
  };
  print('Grade: $grade');
}

• Each line is an arm: pattern => value.
• _ = matches anything. It is like default.
• Arms are separated by commas, and the whole switch ends with ;.

Pattern Matching in Switch

Pattern = a shape that a value is tested against.

• >= 90 is a relational pattern: "is the value at least 90?"
• 'Saturday' || 'Sunday' matches either value.
• _ is a wildcard pattern: it matches anything.

Patterns with ||

void main() {
  var day = 'Saturday';
  var type = switch (day) {
    'Saturday' || 'Sunday' => 'Weekend',
    _ => 'Weekday',
  };
  print(type);
}

You will learn many more patterns in Pattern Matching.

When to Use switch

• One value, many exact choices: a day, a menu option, a grade letter. Use switch.
• Ranges or different variables: marks >= 75, age && hasId. Use if or a switch expression with patterns.
• You need a value back: use a switch expression.

Simple lesson: a switch expression turns a value into another value, arm by arm.

Conditional Expressions

Conditional expression = a short decision that gives a value, on one line.

You already know two of them:

• ?: (from Operators) picks one of two values.
• ?? (from Null Safety) gives a default when a value is null.

One-line decisions

void main() {
  var marks = 64;
  var result = marks >= 35 ? 'Pass' : 'Fail';
  print(result);

  String? nickname;
  var callName = nickname ?? 'Student';
  print('Hello, $callName');
}

When to Use Conditional Expressions

• Use them for a simple choice between two values.
• Use if else when each path does several things.
• Use a switch expression when there are more than two choices.

Simple lesson: use ?: and ?? for short value choices, and if for actions.

TL;DR

1. Condition = a true or false question. Join them with &&, || and !.
2. if = run when true. if else = one of two blocks.

3. else if chain = runs the first true block only.

   • Put the strictest check first.

4. switch = match one value against cases. default catches the rest.

   • No break needed in Dart 3.

5. Switch expression = switch (x) { p => v, _ => w } gives a value.

   • ?: and ?? = one-line value choices.

Common mistakes

Check Yourself

Exercises

What to Remember

• if runs a block when its condition is true. else gives a second path.
• An else if chain runs only the first true block, so put the strictest check first.
• Nest an if only when the inner question depends on the outer one.
• switch matches one value against cases. In Dart 3 it needs no break.
• A switch expression gives back a value, with _ matching everything else.

Next: Loops. You will learn how to repeat code without writing it again and again.