FMath

struct Core Since unknown

#include "Math/UnrealMathUtility.h"

Description

The primary math utility struct in Unreal Engine, providing static functions for arithmetic, interpolation, trigonometry, random number generation, and geometric operations. Inherits platform-specific implementations from FPlatformMath via FGenericPlatformMath.

Caveats & Gotchas

• Many functions have both float and double overloads. When mixing float/double arguments, UE will promote to the higher-precision type via MIX_FLOATS macros — but implicit promotion can silently increase cost in hot paths.
• Trigonometric functions (Sin, Cos, Atan2) take angles in radians. FRotator stores degrees. Use FMath::DegreesToRadians / FMath::RadiansToDegrees to convert.
• FMath::RandRange seeded by FMath::RandInit — the global seed is shared across the process. For deterministic random sequences, use FRandomStream instead.

Example

Common usage in a tick function C++

void AMyActor::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);

	// Smoothly interpolate a float toward a target
	CurrentSpeed = FMath::FInterpTo(CurrentSpeed, TargetSpeed, DeltaTime, 5.0f);

	// Clamp health to valid range
	Health = FMath::Clamp(Health, 0.0f, MaxHealth);

	// Random chance per tick (roughly once per second at 60fps)
	if (FMath::RandRange(0, 59) == 0)
	{
		TriggerRandomEvent();
	}
}

Functions (14)

Math 14

Math

14 ▼

Access	Type	Name	Description
public	function	FMath::Abs	Returns the absolute (non-negative) value of A.
public	function	FMath::Cos	Returns the cosine of an angle given in radians.
public	function	FMath::Sin	Returns the sine of an angle given in radians.
public	function	FMath::Atan2	Returns the angle in radians between the positive X axis and the point (X, Y), in the range [-π, π].
public	function	FMath::Clamp	Clamps a value between a minimum and maximum, inclusive on both ends.
public	function	FMath::FInterpTo	Smoothly moves a float toward a target value at a given speed, independent of frame rate.
public	function	FMath::GetMappedRangeValueClamped	Maps a value from one range to another, clamping the input to the source range first.
public	function	FMath::IsNearlyEqual	Returns true if two floating-point numbers are within a given absolute tolerance of each other.
public	function	FMath::IsNearlyZero	Returns true if a floating-point value is within ErrorTolerance of zero.
public	function	FMath::Lerp	Linearly interpolates between two values.
public	function	FMath::RandRange	Returns a random integer in the inclusive range [Min, Max].
public	function	FMath::Sqrt	Returns the square root of Value.
public	function	FMath::Square	Returns A * A.
public	function	FMath::VInterpTo	Smoothly moves an FVector toward a target vector at a given speed, independently on each axis, frame-rate-independently.

Version History

Introduced in: unknown

Version	Status	Notes
5.6	stable	—

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