diff --git a/src/cis/cis.irp.f b/src/cis/cis.irp.f
index f72197c2..2b16a5f7 100644
--- a/src/cis/cis.irp.f
+++ b/src/cis/cis.irp.f
@@ -74,7 +74,7 @@ subroutine run
     print*,'******************************************************'
     print*,'Excitation energies (au)                     (eV)'
     do i = 2, N_states
-      print*, i ,CI_energy(i) - CI_energy(1), (CI_energy(i) - CI_energy(1))/0.0367502d0
+      print*, i ,CI_energy(i) - CI_energy(1), (CI_energy(i) - CI_energy(1)) * ha_to_ev
     enddo
     print*,''
   endif
diff --git a/src/cisd/cisd.irp.f b/src/cisd/cisd.irp.f
index fca3b10e..6137643c 100644
--- a/src/cisd/cisd.irp.f
+++ b/src/cisd/cisd.irp.f
@@ -95,8 +95,8 @@ subroutine run
     print*,'******************************'
     print*,'Excitation energies (eV)    (CISD+Q)'
     do i = 2, N_states
-      print*, i ,(CI_energy(i) - CI_energy(1))/0.0367502d0, &
-        (cisdq(i) - cisdq(1)) / 0.0367502d0
+      print*, i ,(CI_energy(i) - CI_energy(1)) * ha_to_ev, &
+        (cisdq(i) - cisdq(1)) * ha_to_ev
     enddo
   endif
 
diff --git a/src/iterations/print_extrapolation.irp.f b/src/iterations/print_extrapolation.irp.f
index e07cc1ed..7f602ffb 100644
--- a/src/iterations/print_extrapolation.irp.f
+++ b/src/iterations/print_extrapolation.irp.f
@@ -35,7 +35,7 @@ subroutine print_extrapolated_energy
     do k=2,min(N_iter,8)
       write(*,'(F11.4,X,3(X,F18.8))') pt2_iterations(i,N_iter+1-k), extrapolated_energy(k,i), &
           extrapolated_energy(k,i) - extrapolated_energy(k,1), &
-          (extrapolated_energy(k,i) - extrapolated_energy(k,1) ) * 27.211396641308d0
+          (extrapolated_energy(k,i) - extrapolated_energy(k,1) ) * ha_to_ev
     enddo
     write(*,*)  '=========== ', '=================== ', '=================== ', '==================='
   enddo
diff --git a/src/iterations/print_summary.irp.f b/src/iterations/print_summary.irp.f
index 8e6285e2..a0db3534 100644
--- a/src/iterations/print_summary.irp.f
+++ b/src/iterations/print_summary.irp.f
@@ -36,7 +36,7 @@ subroutine print_summary(e_,pt2_data,pt2_data_err,n_det_,n_configuration_,n_st,s
   write(*,fmt) '# E          ', e_(1:N_states_p)
   if (N_states_p > 1) then
     write(*,fmt) '# Excit. (au)', e_(1:N_states_p)-e_(1)
-    write(*,fmt) '# Excit. (eV)', (e_(1:N_states_p)-e_(1))*27.211396641308d0
+    write(*,fmt) '# Excit. (eV)', (e_(1:N_states_p)-e_(1))*ha_to_ev
   endif
   write(fmt,*) '(A13,', 2*N_states_p, '(1X,F14.8))'
   write(*,fmt) '# PT2 '//pt2_string, (pt2_data % pt2(k), pt2_data_err % pt2(k), k=1,N_states_p)
@@ -47,8 +47,8 @@ subroutine print_summary(e_,pt2_data,pt2_data_err,n_det_,n_configuration_,n_st,s
   if (N_states_p > 1) then
     write(*,fmt) '# Excit. (au)', ( (e_(k)+pt2_data % pt2(k)-e_(1)-pt2_data % pt2(1)), &
       dsqrt(pt2_data_err % pt2(k)*pt2_data_err % pt2(k)+pt2_data_err % pt2(1)*pt2_data_err % pt2(1)), k=1,N_states_p)
-    write(*,fmt) '# Excit. (eV)', ( (e_(k)+pt2_data % pt2(k)-e_(1)-pt2_data % pt2(1))*27.211396641308d0, &
-      dsqrt(pt2_data_err % pt2(k)*pt2_data_err % pt2(k)+pt2_data_err % pt2(1)*pt2_data_err % pt2(1))*27.211396641308d0, k=1,N_states_p)
+    write(*,fmt) '# Excit. (eV)', ( (e_(k)+pt2_data % pt2(k)-e_(1)-pt2_data % pt2(1))*ha_to_ev, &
+      dsqrt(pt2_data_err % pt2(k)*pt2_data_err % pt2(k)+pt2_data_err % pt2(1)*pt2_data_err % pt2(1))*ha_to_ev, k=1,N_states_p)
   endif
   write(fmt,*) '(''# ============'',', N_states_p, '(1X,''=============================''))'
   write(*,fmt)
@@ -82,19 +82,19 @@ subroutine print_summary(e_,pt2_data,pt2_data_err,n_det_,n_configuration_,n_st,s
     print *, 'Variational Energy difference (au | eV)'
     do i=2, N_states_p
       print*,'Delta E = ', (e_(i) - e_(1)), &
-        (e_(i) - e_(1)) * 27.211396641308d0
+        (e_(i) - e_(1)) * ha_to_ev
     enddo
     print *,  '-----'
     print*, 'Variational + perturbative Energy difference (au | eV)'
     do i=2, N_states_p
       print*,'Delta E = ', (e_(i)+ pt2_data % pt2(i) - (e_(1) + pt2_data % pt2(1))), &
-        (e_(i)+ pt2_data % pt2(i) - (e_(1) + pt2_data % pt2(1))) * 27.211396641308d0
+        (e_(i)+ pt2_data % pt2(i) - (e_(1) + pt2_data % pt2(1))) * ha_to_ev
     enddo
     print *,  '-----'
     print*, 'Variational + renormalized perturbative Energy difference (au | eV)'
     do i=2, N_states_p
       print*,'Delta E = ', (e_(i)+ pt2_data % rpt2(i) - (e_(1) + pt2_data % rpt2(1))), &
-        (e_(i)+ pt2_data % rpt2(i) - (e_(1) + pt2_data % rpt2(1))) * 27.211396641308d0
+        (e_(i)+ pt2_data % rpt2(i) - (e_(1) + pt2_data % rpt2(1))) * ha_to_ev
     enddo
   endif
 
diff --git a/src/utils/units.irp.f b/src/utils/units.irp.f
new file mode 100644
index 00000000..914fd041
--- /dev/null
+++ b/src/utils/units.irp.f
@@ -0,0 +1,10 @@
+BEGIN_PROVIDER [double precision, ha_to_ev]
+
+  implicit none
+  BEGIN_DOC
+  ! Converstion from Hartree to eV
+  END_DOC
+
+  ha_to_ev = 27.211396641308d0
+
+END_PROVIDER