C2440: Cannot Convert from ‘type1’ to ‘type2’ in UE5 C++ – What It Means & How to Fix It

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🧠 Why You’re Seeing This Error

The C2440 error means you’re trying to assign or initialize a variable with a value of the wrong type, and C++ doesn’t know how to convert between them.

In Unreal Engine 5, this commonly happens when:

• You assign a pointer to a non-pointer (or vice versa)
• You try to assign nullptr or NULL to an object (not a pointer)
• You mix up FString and const char* or std::string
• You attempt an invalid cast between class types or structures

C++ is strict about type conversions — and UE5 adds its own types (FString, FVector, AActor*, etc.), which don’t auto-convert like standard types.

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💥 Example Error Message

error C2440: '=' : cannot convert from 'FVector' to 'float'

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🛠️ Example Code

FVector Location = FVector(100.f, 200.f, 300.f);
float X = Location; // ❌ C2440: cannot convert from 'FVector' to 'float'

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✅ How to Fix C2440 UE5 – Step-by-Step

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✔️ 1. Use the Correct Member or Conversion

You can’t assign an entire struct (FVector) to a float. Use the specific member instead.

Fix:

float X = Location.X; // ✅ Access just the float you need

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✔️ 2. Watch Out for FString vs const char*

This is a classic UE5 trap. You can’t assign a string literal ("hello") directly to an FString.

Wrong:

FString Name = "Player"; // ❌ C2440: cannot convert from 'const char*' to 'FString'

Fix:

FString Name = FString(TEXT("Player")); // ✅ Correct way in UE5

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✔️ 3. Casting Pointers or Object Types

Trying to convert between unrelated classes? You’ll need an explicit cast, and it has to be safe.

Wrong:

AActor Actor = SomeActorPointer; // ❌ assigning a pointer to an object

Fix:

AActor* Actor = SomeActorPointer; // ✅ use the correct pointer type

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✔️ 4. Use Cast<> for UE5 Class Conversions

Unreal provides the Cast<>() function for converting between UObject-based types.

Fix:

AEnemy* Enemy = Cast(HitActor); // ✅ Runtime-safe casting

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✅ Summary: How to Fix C2440 in UE5

Cause	Fix Example
Type mismatch (struct vs float)	Use specific member (Location.X)
CString vs FString	Wrap in FString(TEXT("..."))
Pointer vs object	Use correct pointer type (AActor*, not AActor)
Class conversion	Use Cast<>() for UObject-based conversions