diff --git a/array.c b/array.c
index 9884092..dfc608f 100644
--- a/array.c
+++ b/array.c
@@ -1892,6 +1892,33 @@ rb_ary_length(VALUE ary)
 
 /*
  *  call-seq:
+ *     ary.float_sum -> float
+ *
+ *  Returns accurate sum of float elements in +self+.
+ *  Uses the Kahan summation algorithm.
+ *
+ *     [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1].float_sum   #=> 1.0
+ *     [].float_sum                                                   #=> 0.0
+ */
+
+static VALUE
+rb_ary_float_sum(VALUE ary)
+{
+  long i;
+  double y,t,c,sum;
+  sum = 0.0;
+  c   = 0.0;
+  for (i=0; i<RARRAY_LEN(ary); i++) {
+    y = RFLOAT_VALUE(rb_ary_entry(ary,i)) - c;
+    t = sum + y;
+    c = (t - sum) - y;
+    sum = t;
+  }
+  return DBL2NUM(sum);
+}
+
+/*
+ *  call-seq:
  *     ary.empty?   -> true or false
  *
  *  Returns +true+ if +self+ contains no elements.
@@ -5719,6 +5746,7 @@ Init_Array(void)
     rb_define_method(rb_cArray, "each_index", rb_ary_each_index, 0);
     rb_define_method(rb_cArray, "reverse_each", rb_ary_reverse_each, 0);
     rb_define_method(rb_cArray, "length", rb_ary_length, 0);
+    rb_define_method(rb_cArray, "float_sum", rb_ary_float_sum, 0);
     rb_define_alias(rb_cArray,  "size", "length");
     rb_define_method(rb_cArray, "empty?", rb_ary_empty_p, 0);
     rb_define_method(rb_cArray, "find_index", rb_ary_index, -1);