---
title: "1.15 Floating-Point Data Types"
description: "C provides `float`, `double`, and `long double` for representing floating-point values. These types differ primarily in their precision and range, with the exact representation and limits depending on the implementation. ``` #include int main() { float a = 3.14f; double…"
url: "https://edcret.in/docs/c-programming/basic-refreshers/1-15-floating-point-data-types/"
updated: "2026-09-06"
category: C Programming / Basic Refreshers
---

# 1.15 Floating-Point Data Types

C provides `float`, `double`, and `long double` for representing floating-point values. These types differ primarily in their precision and range, with the exact representation and limits depending on the implementation.

```
#include <stdio.h>

int main()
{
    float a = 3.14f;
    double b = 3.1415926535;
    long double c = 3.141592653589793L;

    printf("float       = %.9f\n", a);
    printf("double      = %.10f\n", b);
    printf("long double = %.15Lf\n", c);

    return 0;
}
```

### Example Output

The exact precision and output can vary by implementation:

```
float       = 3.140000105
double      = 3.1415926535
long double = 3.141592653589793
```

### Explanation

`float` is generally used when lower storage requirements are more important than precision:

```
float a = 3.14f;
```

The `f` suffix makes `3.14f` a `float` constant.

`double` provides at least as much precision and range as `float`:

```
double b = 3.1415926535;
```

A floating-point constant without a suffix has type `double`.

`long double` provides at least as much precision and range as `double`:

```
long double c = 3.141592653589793L;
```

The `L` suffix specifies a `long double` constant.

### Floating-Point Type Reference

| Type | Minimum relative precision | Minimum range | Common size |
| --- | --- | --- | --- |
| `float` | 6 decimal digits | `10⁻³⁷` to `10³⁷` | 4 bytes |
| `double` | 10 decimal digits | `10⁻³⁷` to `10³⁷` | 8 bytes |
| `long double` | 10 decimal digits | `10⁻³⁷` to `10³⁷` | 8, 12, or 16 bytes |

The C standard specifies minimum characteristics rather than requiring these common sizes.

### Floating-Point Literal Suffixes

| Suffix | Type | Example |
| --- | --- | --- |
| No suffix | `double` | `3.14` |
| `f` / `F` | `float` | `3.14f` |
| `l` / `L` | `long double` | `3.14L` |

Floating-point values are not generally exact representations of decimal fractions. For example, a value such as `0.1` may require rounding when represented in a binary floating-point format.