diff --git doc/compute_gyration.txt doc/compute_gyration.txt
index c704bbd..674275c 100644
--- doc/compute_gyration.txt
+++ doc/compute_gyration.txt
@@ -21,7 +21,7 @@ compute 1 molecule gyration :pre
 
 [Description:]
 
-Define a computation that calculates the radius of gyration Rg of the
+Define a computation that calculates the radius of gyration squared Rg^2 of the
 group of atoms, including all effects due to atoms passing thru
 periodic boundaries.
 
@@ -33,7 +33,7 @@ this formula
 where M is the total mass of the group, Rcm is the center-of-mass
 position of the group, and the sum is over all atoms in the group.
 
-A Rg tensor, stored as a 6-element vector, is also calculated by this
+A Rg^2 tensor, stored as a 6-element vector, is also calculated by this
 compute.  The formula for the components of the tensor is the same as
 the above formula, except that (Ri - Rcm)^2 is replaced by (Rix -
 Rcmx) * (Riy - Rcmy) for the xy component, etc.  The 6 components of
@@ -58,9 +58,8 @@ vector values from a compute as input.  See "Section_howto
 options.
 
 The scalar and vector values calculated by this compute are
-"intensive".  The scalar and vector values will be in distance
-"units"_units.html, since they are the square root of values
-represented by the formula above.
+"intensive".  The scalar and vector values will be in distance squared
+"units"_units.html.
 
 [Restrictions:] none
 
diff --git doc/compute_gyration_molecule.txt doc/compute_gyration_molecule.txt
index 8264713..181bcb7 100644
--- doc/compute_gyration_molecule.txt
+++ doc/compute_gyration_molecule.txt
@@ -26,7 +26,7 @@ compute 2 molecule gyration/molecule tensor :pre
 
 [Description:]
 
-Define a computation that calculates the radius of gyration Rg of
+Define a computation that calculates the radius of gyration squared Rg^2 of
 individual molecules.  The calculation includes all effects due to
 atoms passing thru periodic boundaries.
 
@@ -39,8 +39,8 @@ where M is the total mass of the molecule, Rcm is the center-of-mass
 position of the molecule, and the sum is over all atoms in the
 molecule and in the group.
 
-If the {tensor} keyword is specified, then the scalar Rg value is not
-calculated, but an Rg tensor is instead calculated for each molecule.
+If the {tensor} keyword is specified, then the scalar Rg^2 value is not
+calculated, but an Rg^2 tensor is instead calculated for each molecule.
 The formula for the components of the tensor is the same as the above
 formula, except that (Ri - Rcm)^2 is replaced by (Rix - Rcmx) * (Riy -
 Rcmy) for the xy component, etc.  The 6 components of the tensor are
@@ -79,9 +79,8 @@ section"_Section_howto.html#howto_15 for an overview of LAMMPS output
 options.
 
 All the vector or array values calculated by this compute are
-"intensive".  The vector or array values will be in distance
-"units"_units.html, since they are the square root of values
-represented by the formula above.
+"intensive".  The vector or array values will be in distance squared
+"units"_units.html.
 
 [Restrictions:] none
 
diff --git src/compute_gyration.cpp src/compute_gyration.cpp
index 4389142..1025b8f 100644
--- src/compute_gyration.cpp
+++ src/compute_gyration.cpp
@@ -109,5 +109,5 @@ void ComputeGyration::compute_vector()
   MPI_Allreduce(rg,vector,6,MPI_DOUBLE,MPI_SUM,world);
 
   if (masstotal == 0.0) return;
-  for (int i = 0; i < 6; i++) vector[i] = sqrt(vector[i]/masstotal);
+  for (int i = 0; i < 6; i++) vector[i] = vector[i]/masstotal;
 }
diff --git src/compute_gyration_molecule.cpp src/compute_gyration_molecule.cpp
index 179d4f5..ff3f8e3 100644
--- src/compute_gyration_molecule.cpp
+++ src/compute_gyration_molecule.cpp
@@ -158,7 +158,7 @@ void ComputeGyrationMolecule::compute_vector()
   MPI_Allreduce(rg,vector,nmolecules,MPI_DOUBLE,MPI_SUM,world);
 
   for (int i = 0; i < nmolecules; i++)
-    vector[i] = sqrt(vector[i]/masstotal[i]);
+    vector[i] = vector[i]/masstotal[i];
 }
 
 /* ---------------------------------------------------------------------- */
@@ -212,7 +212,7 @@ void ComputeGyrationMolecule::compute_array()
 
   for (i = 0; i < nmolecules; i++)
     for (j = 0; j < 6; j++)
-      array[i][j] = sqrt(array[i][j]/masstotal[i]);
+      array[i][j] = array[i][j]/masstotal[i];
 }
 
 
diff --git src/fix_spring_rg.cpp src/fix_spring_rg.cpp
index 765edac..ec3940f 100644
--- src/fix_spring_rg.cpp
+++ src/fix_spring_rg.cpp
@@ -66,7 +66,7 @@ void FixSpringRG::init()
   if (rg0_flag) {
     double xcm[3];
     group->xcm(igroup,masstotal,xcm);
-    rg0 = group->gyration(igroup,masstotal,xcm);
+    rg0 = sqrt(group->gyration(igroup,masstotal,xcm));
     rg0_flag = 0;
   }
 
@@ -95,7 +95,7 @@ void FixSpringRG::post_force(int vflag)
 
   double xcm[3];
   group->xcm(igroup,masstotal,xcm);
-  double rg = group->gyration(igroup,masstotal,xcm);
+  double rg = sqrt(group->gyration(igroup,masstotal,xcm));
 
   // apply restoring force to atoms in group
   // f = -k*(r-r0)*mass/masstotal
diff --git src/group.cpp src/group.cpp
index 738c9dd..de01790 100644
--- src/group.cpp
+++ src/group.cpp
@@ -1337,7 +1337,7 @@ double Group::gyration(int igroup, double masstotal, double *cm)
   double rg_all;
   MPI_Allreduce(&rg,&rg_all,1,MPI_DOUBLE,MPI_SUM,world);
 
-  if (masstotal > 0.0) return sqrt(rg_all/masstotal);
+  if (masstotal > 0.0) return rg_all/masstotal;
   return 0.0;
 }
 
@@ -1378,7 +1378,7 @@ double Group::gyration(int igroup, double masstotal, double *cm, int iregion)
   double rg_all;
   MPI_Allreduce(&rg,&rg_all,1,MPI_DOUBLE,MPI_SUM,world);
 
-  if (masstotal > 0.0) return sqrt(rg_all/masstotal);
+  if (masstotal > 0.0) return rg_all/masstotal;
   return 0.0;
 }
 
