Free Pascal uses the math coprocessor (or an emulation) for al its floating-point calculations. The native type for the coprocessor is Double. Other than that, all Turbo Pascal real types are supported. They're listed in table (1.2).
| Type | Range | Significant digits | Size |
| Real | 2.9E-39 .. 1.7E38 | 11-12 | 6 |
| Single | 1.5E-45 .. 3.4E38 | 7-8 | 4 |
| Double | 5.0E-324 .. 1.7E308 | 15-16 | 8 |
| Extended | 1.9E-4951 .. 1.1E4932 | 19-20 | 10 |
Until version 0.9.1 of the compiler, all the real types are mapped to type Double, meaning that they all have size 8. From version 0.9.3, the Extended and single types are defined with the same suze as in Turbo Pascal. The SizeOf function is your friend here.