Difference Between Java Float vs Double Variable

Java Float vs Double

In order to understand the main difference between Java Float vs Double first you must understand what these are and how they are utilized. 

Float and double are the 2 data types used to describe floating-point values in Java. 

This blog article is for you if you want to learn more about the Java programming language and its fundamental data type ideas. 

You can get a better understanding of the fundamental difference between float and double in Java by reading our blog article on the subject. 

We’ve also included a table contrasting the Java data types double and float.

So, first of all, we start with Java and Java data types, and after that, we will discuss the differences between “Java Float vs Double.”

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What is Java?

Java came into existence in 1995. James Gosling and his team members, popularly known as the “Green Team,” started this development at Sun Microsystems.

Java’s original name was “OAK,” but it was later changed to “Java.”Java is just a name; it is not a term. Current Java version, “Java SE 8”. It was released on the market on March 18, 2014.

This is popular now because of its features, such as platform independence. Java is an object-oriented language. It is a high-level language and secure.

Java has built-in features.

  • Object-oriented,
  • simple, and familiar
  • Dynamic
  • Garbage Collected
  • Secure and robust
  • High-Performance
  • Portable
  • Distributed
  • Platform independent
  • Multithreaded

Advantages of Java

  • Simple 
  • Object-Oriented
  • Platform-Independent 
  • Secure
  • Multithreaded

Disadvantages of Java

  • Java is slower than native languages such as C or C++
  • Java Takes More Memory Space.
  • No Control over Garbage collection

Data types in Java

Java has strong data types, contributing to its reliability and safety. In Java, everything has a type, and that type is specified. The amount of data that a variable may store depends on its data type. In Java, there are mainly 2 different sorts of data types. (https://cobblerexpress.com/)

  1. Primitive
  2. Non-Primitive

1. Primitive data types are byte, short, int, long, char, float, double, and boolean are the eight primitive types that are accessible in Java.

2. Non-Primitive data types are Classes, interfaces, and arrays.

As discussed above, now we know Float and Double are data types, now we will discuss in brief about this.

Float Data Types

A 32-bit IEEE 754 floating point with a single precision is the float data type. It has an infinite range of values. 

If you need to maintain memory in big arrays of floating point integers, a float (rather than a double) is advised. For accurate numbers like cash, the float data type should never be utilized.

The single-precision value specified by the float type occupies 32 bits of storage. 

On certain processors, single precision is quicker and uses less storage than double precision, but it loses accuracy when the numbers are either very big or very tiny. When you need a fractional component but just need a little amount of precision, float variables come in handy.

Here are some examples of declarations for float variables:

float high-low temperature; 0.0F is the default value of Float data types.

Double Data Type

Double precision, indicated by the double keyword, stores a value using 64 bits. On certain current processors designed for high-speed mathematical operations, double precision is faster than single precision. 

The double values of all fundamental math functions, including),), and), are returned. Double is the ideal option when handling huge quantities or when precision needs to be maintained through repetitive calculations.

A double-precision 64-bit IEEE 754 floating point is the double data type. It has an unlimited value range. The double data type is widely applied to decimal integers, just as a float. 

Additionally, it’s never a good idea to utilize the double data type for exact numbers like money. 

The Double data type’s default value is 0.0d.

Both data types differ, but there are some similarities between them that we will now discuss.

Similarities in Float and Double Data Types

These are common attributes of float and double data types in a java programming language.

1. Real Numbers

Both double and float represent real numbers in Java i.e. numbers with fractions or decimal points.

2. Approximate types

Both double and float are approximate types, they could be more precise.

3. Comparison

You should use logical operators like  > or < to compare float and double variables instead of = and !=, so they must be more exact.

Java Float vs Double: Difference Table

We have mentioned the 7+ important differences between Float and Double data types in Java with the help of tables. 

ParametersFloat Data TypesDouble Data Types
Memory32 bits or 4 bytes64 bits or 8 bytes
Suffixf’ or ‘F’d’ or ‘D’
Precision6-7 digits decimal points precision15-16 digits decimal points precision
Data LossNo information is lost while converting float to double.Data loss will occur if trying to convert double to float.
Default DatatypeNoYes
Wrapper classjava.lang.Floatjava.lang.Double
Default Value0.0f0.0d

8 differences between Java Float and Double are discussed in brief here.


Regarding memory, float requires 4 bytes (32 bits), while double requires 8 bytes (64 bits).


Double float values are the default type in Java. You must add the suffix “f” or “F” to put them in a float variable.

Consider the number 5.23456. Look at what happens if we put it in the float variable num.

Float num = 5.23456 // compiler error

There are two ways to fix the compiler problem mentioned above.

First, by finishing the number with “f” or “F”

float, num = 5.23456f

// or

float num1 = 5.23456F

Next, typecast it as float, i.e.

float num = (float) 5.23456.

You must add the suffix “d” or “D” for double.

0.5, 0.5d, or 0.5D


A single precision floating point operation is called a “float.” In other terms, a float may provide the precision of 6-7 decimal digits.

Double is a floating point operation with double precision. In other words, double can provide the precision of 15–16 decimal places.

Data Loss

Since float has a smaller range than double, there won’t be any data loss during the conversion.

When double is converted to float, data loss is to be expected.

Default datatype

Float is not the default data type for floating point literals, thus, that is the default data type.

For floating point literals, the default data type is double.

Wrapper class

The wrapper class for float is java. Lang. Float.

Java has a double wrapper class. Lang.Double.

Default value

float default value is 0.0f.

The double default value is 0.0d.


Float data type accuracy is very low.

Double data type accuracy is high.

Which floating-point data type in Java should we use?

Float is less accurate than double. Therefore, use double if a more exact and accurate result is needed. Another justification for double is if the number does not fit inside the float’s range of possibilities. 

If you are limited by memory, we should utilize float instead of double because it takes up half the space.

If you require additional accuracy and there are no memory or space limits, we advise using double rather than float. 

If memory is an issue and 16 precision decimal digits are unnecessary, it is best to use the float.


We have discovered 8 important differences between float vs double in Java today.

This is the only difference between double and float; typecasting from float to double and double to float is acceptable and valid, but it needs to be done properly in the code. The whole point of using double will be lost if you convert regularly and lose accuracy.

Choose and specify whether you want to utilize float or double at the early phases of development, then stick with that choice throughout the program. 

Knowing how certain data is kept in the database is also a good idea. If your application has to be functional, utilize float instead of double since double may cause your software to run slowly when dealing with huge amounts of data. 

Use double if your data requires additional precision.