This is the range of fixnums in bits for the 32-bit builds of 39 Schemes. For this purpose, an exact integer *n* is a fixnum if *n* satisfies the implementation's fixnum? procedure (marked by an asterisk) or if there is no such procedure, then if (eq? *n* *n*) returns #t.

31 bits |
Racket*, Chicken*, Ypsilon*, Elk |

30 bits |
Gambit* , Scheme48/scsh, Guile, Chibi*, Chez*, SCM, Ikarus*/Vicare*, Larceny*, Ypsilon*, Mosh*, IronScheme* (but see below), STklos*, RScheme*, Oaklisp* |

29 bits |
Gauche*, Bigloo*, SigScheme |

26 bits |
MIT* |

16 bits |
Owl Lisp* |

9 bits |
S7 |

No fixnums (even (eq? 0 0) is #f) |
SISC, KSi, TinyScheme, Scheme 9, Dream, BDC, UMB |

Apparently unbounded fixnums |
Shoe, Schemik, VX |

Answer not easily determined |
NexJ, XLisp, rep |

In Kawa and IronScheme all exact integers are boxed, but a short range is preallocated, so that eq? is satisfied: -100 to 1024 for Kawa, -100 to 999 for IronScheme.

These were computed using later versions of many of the above Schemes, so they are not directly comparable.

62 bits |
Racket*, Chicken*, Ypsilon* |

61 bits |
Gauche*, Gambit*, Scheme48/scsh, Guile, Chibi*, SCM, STklos*, Sagittarius* |

60 bits |
Chez, Vicare* |

59 bits |
SigScheme |

56 bits |
MIT* |

31 bits |
Elk, IronScheme* (but see above) |

29 bits |
Larceny*, Mosh*, RScheme* |

16 bits |
Owl Lisp* |

11 bits |
S7 |

8 bits |
BDC |

No fixnums (even (eq? 0 0) is #f) |
SISC, KSi, TinyScheme, Scheme 9, BDC |

Apparently unbounded fixnums |
Shoe, Schemik, NexJ |

Answer not easily determined |
Bigloo*, UMB, XLisp, rep |