diff --git a/src/genworld_gui.cpp b/src/genworld_gui.cpp
index 85647bdb73..94a06e7487 100644
--- a/src/genworld_gui.cpp
+++ b/src/genworld_gui.cpp
@@ -78,7 +78,7 @@ static const NWidgetPart _nested_generate_landscape_widgets[] = {
 			NWidget(NWID_HORIZONTAL), SetPIP(0, 3, 0),
 				/* Left column with labels. */
 				NWidget(NWID_VERTICAL, NC_EQUALSIZE), SetPIP(0, 4, 0),
-					NWidget(WWT_TEXT, COLOUR_ORANGE), SetDataTip(STR_MAPGEN_MAPSIZE, STR_NULL), SetFill(1, 1),
+					NWidget(WWT_TEXT, COLOUR_ORANGE), SetDataTip(STR_MAPGEN_MAPSIZE, STR_MAPGEN_MAPSIZE_TOOLTIP), SetFill(1, 1),
 					NWidget(WWT_TEXT, COLOUR_ORANGE), SetDataTip(STR_MAPGEN_LAND_GENERATOR, STR_NULL), SetFill(1, 1),
 					NWidget(WWT_TEXT, COLOUR_ORANGE), SetDataTip(STR_MAPGEN_NUMBER_OF_TOWNS, STR_NULL), SetFill(1, 1),
 					NWidget(WWT_TEXT, COLOUR_ORANGE), SetDataTip(STR_MAPGEN_TERRAIN_TYPE, STR_NULL), SetFill(1, 1),
@@ -92,9 +92,9 @@ static const NWidgetPart _nested_generate_landscape_widgets[] = {
 				NWidget(NWID_VERTICAL, NC_EQUALSIZE), SetPIP(0, 4, 0),
 					/* Mapsize X * Y. */
 					NWidget(NWID_HORIZONTAL), SetPIP(0, 4, 0),
-						NWidget(WWT_DROPDOWN, COLOUR_ORANGE, WID_GL_MAPSIZE_X_PULLDOWN), SetDataTip(STR_JUST_INT, STR_NULL), SetFill(1, 0),
+						NWidget(WWT_DROPDOWN, COLOUR_ORANGE, WID_GL_MAPSIZE_X_PULLDOWN), SetDataTip(STR_JUST_INT, STR_MAPGEN_MAPSIZE_TOOLTIP), SetFill(1, 0),
 						NWidget(WWT_TEXT, COLOUR_ORANGE), SetDataTip(STR_MAPGEN_BY, STR_NULL), SetPadding(1, 0, 0, 0), SetFill(1, 1),
-						NWidget(WWT_DROPDOWN, COLOUR_ORANGE, WID_GL_MAPSIZE_Y_PULLDOWN), SetDataTip(STR_JUST_INT, STR_NULL), SetFill(1, 0),
+						NWidget(WWT_DROPDOWN, COLOUR_ORANGE, WID_GL_MAPSIZE_Y_PULLDOWN), SetDataTip(STR_JUST_INT, STR_MAPGEN_MAPSIZE_TOOLTIP), SetFill(1, 0),
 					EndContainer(),
 					NWidget(WWT_DROPDOWN, COLOUR_ORANGE, WID_GL_LANDSCAPE_PULLDOWN), SetDataTip(STR_JUST_STRING, STR_NULL), SetFill(1, 0),
 					NWidget(WWT_DROPDOWN, COLOUR_ORANGE, WID_GL_TOWN_PULLDOWN), SetDataTip(STR_JUST_STRING, STR_NULL), SetFill(1, 0),
diff --git a/src/lang/english.txt b/src/lang/english.txt
index c65329dc3e..a69b6b0c14 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -2576,6 +2576,7 @@ STR_SAVELOAD_OSKTITLE                                           :{BLACK}Enter a
 # World generation
 STR_MAPGEN_WORLD_GENERATION_CAPTION                             :{WHITE}World Generation
 STR_MAPGEN_MAPSIZE                                              :{BLACK}Map size:
+STR_MAPGEN_MAPSIZE_TOOLTIP                                      :{BLACK}Select the size of the map in tiles. The number of available tiles will be slightly smaller
 STR_MAPGEN_BY                                                   :{BLACK}*
 STR_MAPGEN_NUMBER_OF_TOWNS                                      :{BLACK}No. of towns:
 STR_MAPGEN_DATE                                                 :{BLACK}Date: