diff --git a/Src/Base/AMReX_MultiFabUtil.H b/Src/Base/AMReX_MultiFabUtil.H
index 0740069c683..8c14adb24f1 100644
--- a/Src/Base/AMReX_MultiFabUtil.H
+++ b/Src/Base/AMReX_MultiFabUtil.H
@@ -334,7 +334,7 @@ namespace amrex
      * Return a HostVector that contains the sum of the given MultiFab data in the plane
      * with the given normal direction.  The size of the vector is
      * domain.length(direction) x ncomp.  The vector is actually a 2D array, where the
-     * element for component icomp at spatial index k is at [icomp*ncomp+k].
+     * element for component icomp at spatial index k is at [icomp+ncomp*k].
      *
      * \param mf MultiFab data for summing
      * \param icomp starting component
diff --git a/Src/Base/AMReX_MultiFabUtil.cpp b/Src/Base/AMReX_MultiFabUtil.cpp
index 98e14650c36..1e04a16693d 100644
--- a/Src/Base/AMReX_MultiFabUtil.cpp
+++ b/Src/Base/AMReX_MultiFabUtil.cpp
@@ -822,7 +822,7 @@ namespace amrex
 #ifdef AMREX_USE_GPU
         if (Gpu::inLaunchRegion())
         {
-            Gpu::DeviceVector<Real> dv(domain.length(direction), Real(0.0));
+            Gpu::DeviceVector<Real> dv(hv.size(), Real(0.0));
             Real* p = dv.data();
 
             for (MFIter mfi(mf); mfi.isValid(); ++mfi) {