diff --git a/core/bootstrap/primitives.factor b/core/bootstrap/primitives.factor
index 10c5bbc4cf..2dfb949b21 100755
--- a/core/bootstrap/primitives.factor
+++ b/core/bootstrap/primitives.factor
@@ -502,6 +502,7 @@ tuple
     { "bignum>" "math.private" "primitive_bignum_greater" ( x y -- ? ) }
     { "bignum>=" "math.private" "primitive_bignum_greatereq" ( x y -- ? ) }
     { "bignum>fixnum" "math.private" "primitive_bignum_to_fixnum" ( x -- y ) }
+    { "bignum>fixnum-strict" "math.private" "primitive_bignum_to_fixnum_strict" ( x -- y ) }
     { "fixnum-shift" "math.private" "primitive_fixnum_shift" ( x y -- z ) }
     { "fixnum/i" "math.private" "primitive_fixnum_divint" ( x y -- z ) }
     { "fixnum/mod" "math.private" "primitive_fixnum_divmod" ( x y -- z w ) }
diff --git a/core/math/integers/integers.factor b/core/math/integers/integers.factor
index 0f777055fd..04918ad9e6 100644
--- a/core/math/integers/integers.factor
+++ b/core/math/integers/integers.factor
@@ -67,10 +67,7 @@ M: fixnum (log2) fixnum-log2 { fixnum } declare ; inline
 M: bignum >fixnum bignum>fixnum ; inline
 M: bignum >bignum ; inline
 M: bignum integer>fixnum bignum>fixnum ; inline
-
-M: bignum integer>fixnum-strict
-    dup bignum>fixnum
-    2dup number= [ nip ] [ drop out-of-fixnum-range ] if ; inline
+M: bignum integer>fixnum-strict bignum>fixnum-strict ; inline
 
 M: bignum hashcode* nip bignum>fixnum ;
 
diff --git a/vm/math.cpp b/vm/math.cpp
index 0fac920e3e..f6419dd025 100644
--- a/vm/math.cpp
+++ b/vm/math.cpp
@@ -6,6 +6,10 @@ void factor_vm::primitive_bignum_to_fixnum() {
   ctx->replace(tag_fixnum(bignum_to_fixnum(untag<bignum>(ctx->peek()))));
 }
 
+void factor_vm::primitive_bignum_to_fixnum_strict() {
+  ctx->replace(tag_fixnum(bignum_to_fixnum_strict(untag<bignum>(ctx->peek()))));
+}
+
 void factor_vm::primitive_float_to_fixnum() {
   ctx->replace(tag_fixnum(float_to_fixnum(ctx->peek())));
 }
diff --git a/vm/primitives.hpp b/vm/primitives.hpp
index 809cba3cac..5e386034a0 100644
--- a/vm/primitives.hpp
+++ b/vm/primitives.hpp
@@ -8,7 +8,8 @@ namespace factor {
       _(bignum_divmod) _(bignum_eq) _(bignum_greater) _(bignum_greatereq)      \
       _(bignum_less) _(bignum_lesseq) _(bignum_log2) _(bignum_mod)             \
       _(bignum_gcd) _(bignum_multiply) _(bignum_not) _(bignum_or)              \
-      _(bignum_shift) _(bignum_subtract) _(bignum_to_fixnum) _(bignum_xor)     \
+      _(bignum_shift) _(bignum_subtract) _(bignum_to_fixnum)                   \
+      _(bignum_to_fixnum_strict) _(bignum_xor)                                 \
       _(bits_double) _(bits_float) _(byte_array) _(callback) _(callstack)      \
       _(callstack_bounds) _(callstack_for) _(callstack_to_array)               \
       _(check_datastack) _(clear_samples) _(clone) _(code_blocks) _(code_room) \
diff --git a/vm/vm.hpp b/vm/vm.hpp
index dfc014f282..9281fdbb88 100644
--- a/vm/vm.hpp
+++ b/vm/vm.hpp
@@ -473,6 +473,7 @@ struct factor_vm {
 
   // math
   void primitive_bignum_to_fixnum();
+  void primitive_bignum_to_fixnum_strict();
   void primitive_float_to_fixnum();
   void primitive_fixnum_divint();
   void primitive_fixnum_divmod();