diff --git a/docs/changes.txt b/docs/changes.txt
index 4a9e3d9b9d..a274b25064 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -121,6 +121,7 @@ All (GUI):
 - Added wxSizerFlags::ReserveSpaceEvenIfHidden() and
   wxRESERVE_SPACE_EVEN_IF_HIDDEN sizer flag.
 - Added wxWindow::ClientToWindowSize() and WindowToClientSize() helpers.
+- Added wxSizer::ComputeFittingClientSize() and ComputeFittingWindowSize().
 
 All (Unix):
 
diff --git a/docs/latex/wx/sizer.tex b/docs/latex/wx/sizer.tex
index db206cb654..7d721b05fb 100644
--- a/docs/latex/wx/sizer.tex
+++ b/docs/latex/wx/sizer.tex
@@ -197,6 +197,48 @@ Here, the sizer will do the actual calculation of its children minimal sizes.
 Detaches all children from the sizer. If \arg{delete\_windows} is \true then child windows will also be deleted.
 
 
+\membersection{wxSizer::ComputeFittingClientSize}\label{wxsizercomputefittingclientsize}
+
+\func{wxSize}{ComputeFittingClientSize}{\param{wxWindow* }{window}}
+
+Computes client area size for \arg{window} so that it matches the 
+sizer's minimal size. Unlike \helpref{GetMinSize}{wxsizergetminsize}, this
+method accounts for other constraints imposed on \arg{window}, namely display's
+size (returned size will never be too large for the display) and maximum
+window size if previously set by
+\helpref{wxWindow::SetMaxSize}{wxwindowsetmaxsize}.
+
+The returned value is suitable for passing to
+\helpref{wxWindow::SetClientSize}{wxwindowsetclientsize} or
+\helpref{wxWindow::SetMinClientSize}{wxwindowsetminclientsize}.
+
+\since{2.8.8}
+
+\wxheading{See also}
+
+\helpref{ComputeFittingWindowSize}{wxsizercomputefittingwindowsize},
+\helpref{Fit}{wxsizerfit}
+
+
+\membersection{wxSizer::ComputeFittingWindowSize}\label{wxsizercomputefittingwindowsize}
+
+\func{wxSize}{ComputeFittingWindowSize}{\param{wxWindow* }{window}}
+
+Like \helpref{ComputeFittingClientSize}{wxsizercomputefittingclientsize},
+but converts the result into \emph{window} size.
+
+The returned value is suitable for passing to
+\helpref{wxWindow::SetSize}{wxwindowsetsize} or
+\helpref{wxWindow::SetMinSize}{wxwindowsetminsize}.
+
+\since{2.8.8}
+
+\wxheading{See also}
+
+\helpref{ComputeFittingClientSize}{wxsizercomputefittingclientsize},
+\helpref{Fit}{wxsizerfit}
+
+
 \membersection{wxSizer::Detach}\label{wxsizerdetach}
 
 \func{bool}{Detach}{\param{wxWindow* }{window}}
@@ -228,6 +270,11 @@ of \helpref{wxBoxSizer}{wxboxsizer}. Returns the new size.
 
 For a top level window this is the total window size, not client size.
 
+\wxheading{See also}
+
+\helpref{ComputeFittingClientSize}{wxsizercomputefittingclientsize},
+\helpref{ComputeFittingWindowSize}{wxsizercomputefittingwindowsize}
+
 
 \membersection{wxSizer::FitInside}\label{wxsizerfitinside}
 
@@ -297,6 +344,13 @@ Returns the minimal size of the sizer. This is either the combined minimal
 size of all the children and their borders or the minimal size set by 
 \helpref{SetMinSize}{wxsizersetminsize}, depending on which is bigger.
 
+Note that the returned value is \emph{client} size, not window size.
+In particular, if you use the value to set toplevel window's minimal or
+actual size, use \helpref{wxWindow::SetMinClientSize}{wxwindowsetminclientsize}
+or \helpref{wxWindow::SetClientSize}{wxwindowsetclientsize}, \emph{not}
+\helpref{wxWindow::SetMinSize}{wxwindowsetminsize}
+or \helpref{wxWindow::SetSize}{wxwindowsetsize}.
+
 
 \membersection{wxSizer::Hide}\label{wxsizerhide}
 
diff --git a/include/wx/sizer.h b/include/wx/sizer.h
index 94bae3bb6e..8cba219c6f 100644
--- a/include/wx/sizer.h
+++ b/include/wx/sizer.h
@@ -562,6 +562,11 @@ public:
 
     virtual void Layout();
 
+#if wxABI_VERSION >= 20808
+    wxSize ComputeFittingClientSize(wxWindow *window);
+    wxSize ComputeFittingWindowSize(wxWindow *window);
+#endif
+
     wxSize Fit( wxWindow *window );
     void FitInside( wxWindow *window );
     void SetSizeHints( wxWindow *window );
diff --git a/src/common/sizer.cpp b/src/common/sizer.cpp
index 81ae4cabf6..de4b8c3bdb 100644
--- a/src/common/sizer.cpp
+++ b/src/common/sizer.cpp
@@ -809,7 +809,7 @@ void wxSizer::DeleteWindows()
     }
 }
 
-wxSize wxSizer::Fit( wxWindow *window )
+wxSize wxSizer::ComputeFittingWindowSize(wxWindow *window)
 {
     // take the min size by default and limit it by max size
     wxSize size = GetMinWindowSize(window);
@@ -842,9 +842,20 @@ wxSize wxSizer::Fit( wxWindow *window )
     if ( sizeMax.y != wxDefaultCoord && size.y > sizeMax.y )
         size.y = sizeMax.y;
 
+    return size;
+}
 
-    window->SetSize( size );
+wxSize wxSizer::ComputeFittingClientSize(wxWindow *window)
+{
+    wxCHECK_MSG( window, wxDefaultSize, "window can't be NULL" );
 
+    return window->WindowToClientSize(ComputeFittingWindowSize(window));
+}
+
+wxSize wxSizer::Fit( wxWindow *window )
+{
+    wxSize size = ComputeFittingWindowSize(window);
+    window->SetSize(size);
     return size;
 }
 
diff --git a/version-script.in b/version-script.in
index 6a250aa781..5948e7915c 100644
--- a/version-script.in
+++ b/version-script.in
@@ -37,6 +37,8 @@
         *wxRichTextCtrl*SetTextCursor*;
         *wxRichTextCtrl*SetURLCursor*;
         *wxScrollHelper*HandleOnChildFocus*;
+        *wxSizer*ComputeFittingClientSize*;
+        *wxSizer*ComputeFittingWindowSize*;
         *wxSizerFlags*ReserveSpaceEvenIfHidden*;
         *wxSizerItem*ShouldAccountFor*;
         *wxWindowBase*ClientToWindowSize*;