Difference Between useMemo and useCallback

Both hooks are used for optimization in React.

useMemo

useMemo memoizes a computed value.

example.tsx
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const value = useMemo(() => {
  return expensiveCalculation(data);
}, [data]);

useCallback

useCallback memoizes a function reference.

example.tsx
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const callback = useCallback(() => {
  handleSubmit();
}, []);

Key Difference

• useMemo → memoizes values
• useCallback → memoizes functions

Interview Tip

Use them only when optimization is actually needed.