diff --git a/core_compiler.h b/core_compiler.h
index b8ace23..1e38c5a 100644
--- a/core_compiler.h
+++ b/core_compiler.h
@@ -242,9 +242,9 @@ lex_init(Allocator *token_string_arena, Allocator *map_allocator, Lexer *l){
   l->interns.first_keyword = keyword_struct.str;
   l->interns.last_keyword  = keyword_enum.str;
 
-  intern_sizeof = l->intern("size_of"_s);
-  intern_lengthof = l->intern("length_of"_s);
-  intern_alignof = l->intern("align_of"_s);
+  intern_sizeof = l->intern("SizeOf"_s);
+  intern_lengthof = l->intern("Length"_s);
+  intern_alignof = l->intern("AlignOf"_s);
   intern_foreign = intern_string(&l->interns, "foreign"_s);
   intern_strict = intern_string(&l->interns, "strict"_s);
   intern_void = intern_string(&l->interns, "void"_s);
diff --git a/core_main.cpp b/core_main.cpp
index ac2e3b4..7ef42cd 100644
--- a/core_main.cpp
+++ b/core_main.cpp
@@ -61,7 +61,7 @@ For modules it's a bit different cause they should be distributed as valid.
 
 
 - [ ] Builtin data structures
-  - [ ] Fix length_of etc. they should be function calls not operators
+  - [ ] Fix Length etc. they should be function calls not operators
   - [ ] Strings probably should have len() instead of string.len
   - [ ] Slices
     - [ ] Some way to take slice of data
diff --git a/core_typechecking.cpp b/core_typechecking.cpp
index 67fff2f..e0d7f42 100644
--- a/core_typechecking.cpp
+++ b/core_typechecking.cpp
@@ -1228,7 +1228,7 @@ resolve_expr(Ast_Expr *ast, Resolve_Flag flags, Ast_Type *compound_context){
 
         Operand name = resolve_expr(expr, inherit_flag(flags, AST_CANT_BE_NULL));
         if(!name.is_const){
-          compiler_error(node->pos, "size_of requires a constant value");
+          compiler_error(node->pos, "SizeOf requires a constant value");
         }
 
         Ast_Type *type = name.type == type_type ? name.type_val : name.type;
@@ -1262,7 +1262,7 @@ resolve_expr(Ast_Expr *ast, Resolve_Flag flags, Ast_Type *compound_context){
       else if(expr_atom_is_equal_intern(node->name, intern_alignof)){
         Ast_Expr *expr = unpack_ast_call_expr_for_builtin(node);
         Operand name = resolve_expr(expr, inherit_flag(flags, AST_CANT_BE_NULL));
-        if(!name.is_const) compiler_error(node->pos, "align_of requires a constant value");
+        if(!name.is_const) compiler_error(node->pos, "AlignOf requires a constant value");
         Ast_Type *type = name.type == type_type ? name.type_val : name.type;
         Value v = value_int(type->align);
         rewrite_into_const(node, Ast_Builtin, v);
diff --git a/examples/arrays_and_slices.kl b/examples/arrays_and_slices.kl
index c5bf450..201182b 100644
--- a/examples/arrays_and_slices.kl
+++ b/examples/arrays_and_slices.kl
@@ -14,8 +14,8 @@ be nice if handling of that was simplified.
 main :: (): int
   static_array: [8]int
 
-  // We can get size of array using length_of builtin
-  #Assert(length_of(static_array) == 8)
+  // We can get size of array using Length builtin
+  #Assert(Length(static_array) == 8)
 
   // Accessing values is like in C
   // Variables are zeroed by default
@@ -39,7 +39,7 @@ main :: (): int
   slice: []int = static_array
 
   // We can't do a compile time Assert anymore
-  Assert(length_of(slice) == 8)
+  Assert(Length(slice) == 8)
   Assert(slice[4] == 1)
 
   // After we loop and reassign slice values
diff --git a/examples/drawing_to_screen_using_windows_api.kl b/examples/drawing_to_screen_using_windows_api.kl
index e6ecd41..42b9999 100644
--- a/examples/drawing_to_screen_using_windows_api.kl
+++ b/examples/drawing_to_screen_using_windows_api.kl
@@ -26,7 +26,7 @@ CreateBitmap :: (size: Vec2I, bottom_up: Bool = true): Windows_Bitmap
 
   bminfo := BITMAPINFO{
     BITMAPINFOHEADER{
-      biSize          = 40, // @todo!!! size_of(BITMAPINFOHEADER),
+      biSize          = 40, // @todo!!! SizeOf(BITMAPINFOHEADER),
       biWidth         = size.x->LONG,
       biHeight        = size.y->LONG,
       biPlanes        = 1,
diff --git a/examples/runtime_type_information.kl b/examples/runtime_type_information.kl
index e6c4186..fc20f1a 100644
--- a/examples/runtime_type_information.kl
+++ b/examples/runtime_type_information.kl
@@ -14,10 +14,10 @@ main :: (): int
     return 1
 
   if type_info.type == S64
-    // We can use size_of and align_of operators
+    // We can use SizeOf and AlignOf operators
     // to figure out the type alignment and it's size
-    Assert(type_info.size == size_of(S64))
-    Assert(type_info.align == align_of(S64))
+    Assert(type_info.size == SizeOf(S64))
+    Assert(type_info.align == AlignOf(S64))
 
   else;; Assert(false, "We expected S64 here! What a boomer!")
 
diff --git a/modules/base.kl b/modules/base.kl
index c0b90d6..0bd9942 100644
--- a/modules/base.kl
+++ b/modules/base.kl
@@ -74,10 +74,10 @@ Utf32ToUtf16 :: (codepoint: U32): [2]U16, S64
 StringToString16 :: (arena: *Arena, in: String): String16
   in_str := &in[0]
   // @Note(Krzosa): Should be more then enough space
-  alloc_size := (length_of(in)*2)+1
+  alloc_size := (Length(in)*2)+1
   result := String16{str = PushSize(arena, alloc_size->U64)}
-  for i := 0, i < length_of(in)
-    s32, s32_len := Utf8ToUtf32(in_str + i, length_of(in) - i)
+  for i := 0, i < Length(in)
+    s32, s32_len := Utf8ToUtf32(in_str + i, Length(in) - i)
     if s32_len != 0
       i += s32_len
       s16, s16_len := Utf32ToUtf16(s32)
diff --git a/modules/os_windows.kl b/modules/os_windows.kl
index 3d11282..55805d5 100644
--- a/modules/os_windows.kl
+++ b/modules/os_windows.kl
@@ -99,9 +99,9 @@ Print :: (string: String, args: ..)
   buffer_len: S64
 
   arg_counter := 0
-  for i := 0, i < length_of(string), i+=1
+  for i := 0, i < Length(string), i+=1
     if string[i] == '%'
-      Assert(arg_counter < length_of(args), "Passing too many [%] to a print lambda")
+      Assert(arg_counter < Length(args), "Passing too many [%] to a print lambda")
       arg := args[arg_counter++]
 
       if arg.type == S64