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<log10max>
^Math FunctionsLast updated: Mon, 26 Oct 2026

log1p

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

log1p — Returns log(1 + number), computed in a way that is accurate even when the value of number is close to zero

Description

function log1p(float $num): float

log1p() returns log(1 + num) computed in a way that is accurate even when the value of num is close to zero. log() might only return log(1) in this case due to lack of precision.

Parameters

num

The argument to process

Return Values

log(1 + num)

See Also

  • expm1() - Returns exp($num) - 1, computed in a way that is accurate even when the value of number is close to zero
  • log() - Natural logarithm
  • log10() - Base-10 logarithm


<log10max>
^Math FunctionsLast updated: Mon, 26 Oct 2026