Why can't float/double MinValue/MaxValue fit inside a decimal?

Question

Consider the following code:

float value = float.MinValue;
decimal dec = (decimal) value;

Unhandled exception. System.OverflowException: Value was either too large or too small for a Decimal.

The same applies for float.MinValue, float.MaxValue, double.MinValue, and double.MaxValue.

If float is 32-bit and double is 64-bit, why don't their min/max values fit inside a decimal which is 128-bit?

Answer 1

The reason is that deciaml is narrower than float or double.

// decimal.MaxValue
79228162514264337593543950335

// decimal.MinValue
-79228162514264337593543950335

// float.MaxValue
3.402823E+38

// float.MinValue
-3.402823E+38

// double.MaxValue
1.79769313486232E+308

// double.MinValue
-1.79769313486232E+308