diff --git a/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.C b/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.C
index 3264cfd318..89b045da1a 100644
--- a/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.C
+++ b/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.C
@@ -62,7 +62,7 @@ void Foam::functionObjects::energySpectrum::calcAndWriteSpectrum
     const vectorField& C,
     const vector& c0,
     const vector& deltaC,
-    const Vector<label>& N,
+    const Vector<int>& N,
     const scalar kappaNorm
 )
 {
@@ -72,7 +72,7 @@ void Foam::functionObjects::energySpectrum::calcAndWriteSpectrum
         fft::forwardTransform
         (
             ReComplexField(U),
-            List<label>({N.x(), N.y(), N.z()})
+            List<int>({N.x(), N.y(), N.z()})
         )
        /scalar(cmptProduct(N))
     );
@@ -159,7 +159,7 @@ bool Foam::functionObjects::energySpectrum::read(const dictionary& dict)
     const vector L(meshBb.max() - meshBb.min());
     const vector nCellXYZ(cmptDivide(L, cellBb.max() - cellBb.min()));
 
-    N_ = Vector<label>
+    N_ = Vector<int>
     (
         round(nCellXYZ.x()),
         round(nCellXYZ.z()),
diff --git a/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.H b/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.H
index 9958d6edbe..9af3cefe04 100644
--- a/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.H
+++ b/src/functionObjects/randomProcesses/energySpectrum/energySpectrum.H
@@ -96,7 +96,7 @@ protected:
         word UName_;
 
         //- Number of cells in I-J-K directions
-        Vector<label> N_;
+        Vector<int> N_;
 
         //- Reference point
         vector c0_;
@@ -121,7 +121,7 @@ protected:
             const vectorField& C,
             const vector& c0,
             const vector& deltaC,
-            const Vector<label>& N,
+            const Vector<int>& N,
             const scalar kappaNorm
         );