diff --git a/src/postProcessing/functionObjects/forces/forces/forces.C b/src/postProcessing/functionObjects/forces/forces/forces.C
index dfc63544..0d504553 100644
--- a/src/postProcessing/functionObjects/forces/forces/forces.C
+++ b/src/postProcessing/functionObjects/forces/forces/forces.C
@@ -377,7 +377,7 @@ void Foam::forces::applyBins
 
         forAll(dd, i)
         {
-            label bini = min(max(floor(dd[i]/binDx_), 0), force_[0].size());
+            label bini = min(max(floor(dd[i]/binDx_), 0), force_[0].size() - 1);
             force_[0][bini] += fN[i];
             force_[1][bini] += fT[i];
             force_[2][bini] += fP[i];