diff --git a/Tests/LibWeb/Layout/expected/grid/1fr-1000px.txt b/Tests/LibWeb/Layout/expected/grid/1fr-1000px.txt
new file mode 100644
index 00000000000..a668f7701de
--- /dev/null
+++ b/Tests/LibWeb/Layout/expected/grid/1fr-1000px.txt
@@ -0,0 +1,13 @@
+Viewport <#document> at (0,0) content-size 800x600 children: not-inline
+  BlockContainer <html> at (0,0) content-size 800x33 [BFC] children: not-inline
+    Box <body> at (8,8) content-size 784x17 [GFC] children: not-inline
+      BlockContainer <nav> at (8,8) content-size 39.78125x17 [BFC] children: inline
+        frag 0 from TextNode start: 0, length: 5, rect: [8,8 39.78125x17] baseline: 13.296875
+            "Hello"
+        TextNode <#text>
+
+ViewportPaintable (Viewport<#document>) [0,0 800x600]
+  PaintableWithLines (BlockContainer<HTML>) [0,0 800x33]
+    PaintableBox (Box<BODY>) [8,8 784x17]
+      PaintableWithLines (BlockContainer<NAV>) [8,8 39.78125x17]
+        TextPaintable (TextNode<#text>)
diff --git a/Tests/LibWeb/Layout/input/grid/1fr-1000px.html b/Tests/LibWeb/Layout/input/grid/1fr-1000px.html
new file mode 100644
index 00000000000..fe04aebf2fa
--- /dev/null
+++ b/Tests/LibWeb/Layout/input/grid/1fr-1000px.html
@@ -0,0 +1,12 @@
+<!doctype html><style>                    
+    * {    
+        outline: 1px solid black;    
+    }    
+    body {    
+        display: grid;    
+        grid-template-columns: 1fr 1000px;                                      
+    }    
+    nav {    
+        background: pink;    
+    }      
+</style><body><nav>Hello</nav>
\ No newline at end of file
diff --git a/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp b/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
index eb443015677..010bc872bda 100644
--- a/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
+++ b/Userland/Libraries/LibWeb/Layout/GridFormattingContext.cpp
@@ -24,9 +24,19 @@ GridFormattingContext::GridTrack GridFormattingContext::GridTrack::create_from_d
         };
     }
 
+    // https://drafts.csswg.org/css-grid-2/#algo-terms
+    // min track sizing function:
+    // If the track was sized with a minmax() function, this is the first argument to that function.
+    // If the track was sized with a <flex> value or fit-content() function, auto. Otherwise, the track’s sizing function.
+    auto min_track_sizing_function = definition.grid_size();
+    if (min_track_sizing_function.is_flexible_length()) {
+        min_track_sizing_function = CSS::GridSize::make_auto();
+    }
+    auto max_track_sizing_function = definition.grid_size();
+
     return GridTrack {
-        .min_track_sizing_function = definition.grid_size(),
-        .max_track_sizing_function = definition.grid_size(),
+        .min_track_sizing_function = min_track_sizing_function,
+        .max_track_sizing_function = max_track_sizing_function,
     };
 }
 
@@ -766,7 +776,7 @@ void GridFormattingContext::increase_sizes_to_accommodate_spanning_items_crossin
         });
 
         auto item_spans_tracks_with_flexible_sizing_function = any_of(spanned_tracks, [](auto& track) {
-            return track.min_track_sizing_function.is_flexible_length() || track.max_track_sizing_function.is_flexible_length();
+            return track.max_track_sizing_function.is_flexible_length();
         });
         if (item_spans_tracks_with_flexible_sizing_function)
             continue;
@@ -867,7 +877,7 @@ void GridFormattingContext::increase_sizes_to_accommodate_spanning_items_crossin
         });
 
         auto item_spans_tracks_with_flexible_sizing_function = any_of(spanned_tracks, [](auto& track) {
-            return track.min_track_sizing_function.is_flexible_length() || track.max_track_sizing_function.is_flexible_length();
+            return track.max_track_sizing_function.is_flexible_length();
         });
         if (!item_spans_tracks_with_flexible_sizing_function)
             continue;
@@ -877,7 +887,7 @@ void GridFormattingContext::increase_sizes_to_accommodate_spanning_items_crossin
         auto item_minimum_contribution = calculate_minimum_contribution(item, dimension);
         distribute_extra_space_across_spanned_tracks_base_size(dimension,
             item_minimum_contribution, SpaceDistributionPhase::AccommodateMinimumContribution, spanned_tracks, [&](GridTrack const& track) {
-                return track.min_track_sizing_function.is_flexible_length();
+                return track.max_track_sizing_function.is_flexible_length();
             });
 
         for (auto& track : spanned_tracks) {
@@ -2286,14 +2296,23 @@ CSSPixels GridFormattingContext::automatic_minimum_size(GridItem const& item, Gr
     // in a given axis is the content-based minimum size if all of the following are true:
     // - it is not a scroll container
     // - it spans at least one track in that axis whose min track sizing function is auto
-    // FIXME: - if it spans more than one track in that axis, none of those tracks are flexible
+    // - if it spans more than one track in that axis, none of those tracks are flexible
     auto const& tracks = dimension == GridDimension::Column ? m_grid_columns : m_grid_rows;
     auto item_track_index = item.raw_position(dimension);
+    auto item_track_span = item.span(dimension);
 
-    // FIXME: Check all tracks spanned by an item
     AvailableSize const& available_size = dimension == GridDimension::Column ? m_available_space->width : m_available_space->height;
-    auto item_spans_auto_tracks = tracks[item_track_index].min_track_sizing_function.is_auto(available_size);
-    if (item_spans_auto_tracks && !item.box->is_scroll_container()) {
+
+    bool spans_auto_tracks = false;
+    bool spans_flexible_tracks = false;
+    for (size_t index = 0; index < item_track_span; index++) {
+        auto const& track = tracks[item_track_index + index];
+        if (track.max_track_sizing_function.is_flexible_length())
+            spans_flexible_tracks = true;
+        if (track.min_track_sizing_function.is_auto(available_size))
+            spans_auto_tracks = true;
+    }
+    if (spans_auto_tracks && !item.box->is_scroll_container() && (item_track_span == 1 || !spans_flexible_tracks)) {
         return content_based_minimum_size(item, dimension);
     }
 
