diff --git a/pyerrors/correlators.py b/pyerrors/correlators.py
index 6a2108f4..c2ae3eda 100644
--- a/pyerrors/correlators.py
+++ b/pyerrors/correlators.py
@@ -171,7 +171,7 @@ class Corr:
         if self.T % 2 != 0:
             raise Exception("Can not symmetrize odd T")
 
-        if not all([o.is_zero_within_error() for o in self.content[0]]):
+        if not all([o.is_zero_within_error(3) for o in self.content[0]]):
             warnings.warn("Correlator does not seem to be anti-symmetric around x0=0.", RuntimeWarning)
 
         newcontent = [self.content[0]]