diff --git a/src/consts.zig b/src/consts.zig
index c039028..525a973 100644
--- a/src/consts.zig
+++ b/src/consts.zig
@@ -19,8 +19,9 @@ pub const history = struct {
 };
 
 pub const lookup = struct {
-    pub const bits = 17;
+    pub const bits = 15;
     pub const len = 1 << bits;
+    pub const shift = 32 - bits;
 };
 
 // TODO: organize this
diff --git a/src/deflate.zig b/src/deflate.zig
index b5d5024..0d244af 100644
--- a/src/deflate.zig
+++ b/src/deflate.zig
@@ -410,7 +410,8 @@ test "StreamWindow slide" {
 test "struct sizes" {
     try expect(@sizeOf(Token) == 4);
     try expect(@sizeOf(Tokens) == 131_080);
-    try expect(@sizeOf(Lookup) == 393_216);
+    // print("size of Lookup {d}\n", .{@sizeOf(Lookup)});
+    try expect(@sizeOf(Lookup) == 196_608);
 }
 
 const Tokens = struct {