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Basics of Numbers in Dart

Last Updated : 15 Jul, 2025

Like other languages, Dart Programming also supports numerical values as Number objects. The number in Dart Programming is the data type that is used to hold the numeric value.

Dart numbers can be classified as: 
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int (Integer)

The int data type is used to represent whole numbers.

Declaring Integer in Dart

int var_name;

Example :


double (Floating-Point Number)

The double data type is used to represent 64-bit floating-point numbers.

Declaring Double in Dart

double var_name;

Example :


Example Usage :


Output:

2
1.5

Note: The num is actually the superclass of int and double, means int and double extend num.


Parsing in Dart

The parse() function converts a valid numeric string into a number, but if the string is not numeric, it throws a FormatException.

Example :


Output:

Sum = 3.34


Properties of Numbers in Dart

Property

Description

hashcode

This property is used to get the hash code of the given number

isFinite

If the given number is finite, then this property will return true

isInfinite

If the number is infinite, then this property will return true

isNan

(Not a Number) returns true if the number is not a valid numeric value, not based on negativity.

isNegative

If the number is negative then this property will return true

sign

This property is used to get -1, 0, or 1 depending upon the sign of the given number

isEven

If the given number is an even then this property will return true

isOdd

If the given number is odd then this property will return true

Implementation of Properties:


Output:

Hash code of num1: 10
Hash code of num2: 250189098
Is num1 finite? true
Is num3 finite? false
Is num3 infinite? true
Is num1 infinite? false
Is num4 NaN? true
Is num1 NaN? false
Is num2 negative? true
Is num1 negative? false
Sign of num1: 1
Sign of num2: -1
Sign of 0: 0
Is num1 even? true
Is num2 even? false
Is num1 odd? false
Is num2 odd? true


Methods of Numbers in Dart

Method

Description

abs()

This method gives the absolute value of the given number

ceil()

This method gives the ceiling value of the given number

floor()

This method gives the floor value of the given number

compareTo()

This method compares the value with other numbers

remainder()

This method gives the truncated remainder after dividing the two numbers

round()

This method returns the round of the number

toDouble()

This method gives the double equivalent representation of the number

toInt()

This method returns the integer equivalent representation of the number

toString()

This method returns the String equivalent representation of the number

truncate()

This method returns the integer after discarding fraction digits


Implementation of methods :


Output:

Absolute Value: 12.75
Ceiling Value: -12
Floor Value: -13
Compare To (10): -1
Remainder when divided by 5: -2.75
Rounded Value: -13
Integer to Double: 15
Double to Integer: -12
Number as String: -12.75
Truncated Value: -12


Some try-error for num

Example 1: Using num to Store Different Number Types

That means we can assign an int to a double, but assigning a double to an int directly will cause an error. You need to use .toInt().


Example 2: Assigning Values Between int and double

We can store the int value into the double data type but we can't store double value in int type.


Dart uses the int type for whole numbers and the double type for floating-point numbers. The num type serves as the parent class for both int and double, which provides flexibility in number storage. Dart also offers a variety of powerful properties and methods to work with numbers efficiently. You can convert strings to numbers by using the num.parse() method.

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