The **`log10()` function** in PHP uses *base 10* to calculate the *logarithm* of a number.

Figure 1, below, shows the mathematical representation of the `log10()` function and the corresponding representation in PHP.


# 
#  Syntax

---
```php
float log10(number)
```
---

# 
## Parameter

This function requires a number whose logarithm base 10 must be calculated and greater than zero.

* If the number is `zero`, then this function outputs `-Inf`.

* If the number is `negative`, this function outputs `NaN`.

##
## Return value
`log10()` uses base 10 to return the logarithm of a number.

<?php
echo("log10(10): ");
echo (log10(10));
echo("\n");
echo("log10(2): ");
echo (log10(2));
?>	

<?php
#error outputs
echo("log10(0): ");
echo (log10(0));
echo("\n");
echo("log10(-1): ");
echo (log10(-1));
?>


What is log10() in PHP?

Calculates base 10 logarithm of a number, returning -Inf for zero and NaN for negative input.

What is log10() in PHP?

Syntax

Parameter

Return value

Code