diff --git a/python/amunpy/src/amunpy/amun.py b/python/amunpy/src/amunpy/amun.py
index c6be042..1442334 100644
--- a/python/amunpy/src/amunpy/amun.py
+++ b/python/amunpy/src/amunpy/amun.py
@@ -181,7 +181,7 @@ class Amun:
         if 'dens' in self.variables:
             self.variables['density']                       = 'dens'
             self.variables['logarithm of density']          = 'logd'
-        if 'pres' in self.variables:
+        if 'pres' in self.variables or self.attributes['eos'] == 'iso':
             self.variables['pressure']                      = 'pres'
             self.variables['logarithm of pressure']         = 'logp'
         if all(v in self.variables for v in ['velx','vely','velz']):
@@ -258,8 +258,16 @@ class Amun:
                 dset[p,...] = self.chunks[chunk_number]['levels'][p]
         elif dataset == 'logd':
             dset = numpy.log10(self.__read_binary_data__('dens', chunk_number))
+        elif dataset == 'pres':
+            if self.attributes['eos'] == 'iso':
+                dset = self.__read_binary_data__('dens', chunk_number) * self.attributes['sound_speed']**2
+            else:
+                dset = self.__read_binary_data__('pres', chunk_number)
         elif dataset == 'logp':
-            dset = numpy.log10(self.__read_binary_data__('pres', chunk_number))
+            if self.attributes['eos'] == 'iso':
+                dset = numpy.log10(self.__read_binary_data__('dens', chunk_number) * self.attributes['sound_speed']**2)
+            else:
+                dset = numpy.log10(self.__read_binary_data__('pres', chunk_number))
         elif dataset == 'velo':
             tmp = self.__read_binary_data__('velx', chunk_number)
             dset = tmp**2