diff --git a/kerncraft/kernel.py b/kerncraft/kernel.py
index d3f0c44..c48fc49 100755
--- a/kerncraft/kernel.py
+++ b/kerncraft/kernel.py
@@ -37,6 +37,7 @@
 from . import incore_model
 from .pycparser_utils import clean_code, replace_id
 
+from kerncraft.symbolic.utils import int_ceil
 
 @contextmanager
 def set_recursionlimit(new_limit):
@@ -389,7 +390,7 @@ def iteration_length(self, dimension=None):
 
         for var_name, start, end, incr in loops:
             # This unspools the iterations:
-            length = end-start
+            length = int_ceil((end-start), incr)
             total_length = total_length*length
         return self.subs_consts(total_length)
 
@@ -483,7 +484,7 @@ def global_iterator_to_indices(self, git=None):
             loop_var = symbol_pos_int(var_name)
 
             # This unspools the iterations:
-            length = end-start  # FIXME is incr handled correct here?
+            length = int_ceil((end-start), incr)
             counter = start+(((global_iterator*last_incr) // total_length)*incr) % length
             total_length = total_length*length
             last_incr = incr
@@ -511,7 +512,7 @@ def global_iterator(self):
         total_length = sympy.Integer(1)
         for var_name, start, end, incr in reversed(self._loop_stack):
             loop_var = symbol_pos_int(var_name)
-            length = end - start  # FIXME is incr handled correct here?
+            length = int_ceil((end-start), incr)
             global_iterator += (loop_var - start) * total_length
             total_length *= length
         return global_iterator
diff --git a/kerncraft/symbolic/__init__.py b/kerncraft/symbolic/__init__.py
new file mode 100644
index 0000000..b63a01f
--- /dev/null
+++ b/kerncraft/symbolic/__init__.py
@@ -0,0 +1 @@
+from kerncraft.symbolic.utils import int_ceil, int_floor
diff --git a/kerncraft/symbolic/utils.py b/kerncraft/symbolic/utils.py
new file mode 100644
index 0000000..5099398
--- /dev/null
+++ b/kerncraft/symbolic/utils.py
@@ -0,0 +1,19 @@
+import sympy
+
+class int_floor(sympy.Function):
+    @classmethod
+    def eval(cls, x, y):
+        if x.is_Number and y.is_Number:
+            return x // y
+
+    def _eval_is_integer(self):
+        return True
+
+class int_ceil(sympy.Function):
+    @classmethod
+    def eval(cls, x, y):
+        if x.is_Number and y.is_Number:
+            return sympy.ceiling(x / y)
+
+    def _eval_is_integer(self):
+        return True