The key difference between float and double is their precision and storage size. A float is a 32-bit single-precision data type that can store up to 7 decimal digits, making it less precise. A double, on the other hand, is a 64-bit double-precision data type that can store up to 15–16 decimal digits, offering higher precision for calculations. Due to its size, double consumes more memory compared to float. Float is often used for performance-critical applications where precision isn’t as crucial, while double is preferred for applications requiring high precision, such as scientific computations.