diff --git a/da/tools/MixingratioToPermil.py b/da/tools/MixingratioToPermil.py
new file mode 100755
index 0000000000000000000000000000000000000000..91c3f15f67c8b1feffd162ee2d2b24be57fa3104
--- /dev/null
+++ b/da/tools/MixingratioToPermil.py
@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+# MixingratioToPermil.py
+
+"""
+Author : ivar 
+
+Revision History:
+File created on 11 May 2012.
+
+"""
+
+
+def MixingratioToPermil(filename,simulated):
+    """ Converts 13C mixing ratios to permil values"""
+    import da.tools.io4 as io
+    import logging
+    import numpy as np
+
+    pdb         = 0.011112
+
+    trlength=len(simulated[0,:])
+    memlength=trlength/2
+    simulated=simulated #*1.e6 #convert to ppm
+ #   np.set_printoptions(threshold=np.nan)
+ #   msg='simulated shape',simulated.shape;logging.info(msg)
+ #   msg='simulated',simulated[0,0],simulated[0,40];logging.info(msg)
+ #   msg='simulated',simulated ;logging.info(msg)
+    simulated=np.float64(simulated)
+    simulated[:,memlength:trlength]=1000.*((simulated[:,memlength:trlength]/simulated[:,0:memlength]/pdb)-1.)
+ #   msg='simulated',simulated[0,0],simulated[0,40],memlength,trlength,pdb;logging.info(msg)
+ #   msg='simulated',simulated ;logging.info(msg)
+
+
+
+
+    return simulated
+
+
+if __name__ == "__main__":
+    pass