diff --git a/src/link/MachO/Archive.zig b/src/link/MachO/Archive.zig
index 54c00e33eef74c485876e44382b25b3bf2eff262..a733e1a5b6c9b3911e27e5e60e1ae4e6faed54a5 100644
--- a/src/link/MachO/Archive.zig
+++ b/src/link/MachO/Archive.zig
@@ -89,12 +89,13 @@ pub fn unpack(self: *Archive, macho_file: *MachO, path: Path, handle_index: File
 pub fn writeHeader(
     object_name: []const u8,
     object_size: usize,
-    format: Format,
     writer: *Writer,
 ) !void {
     var hdr: ar_hdr = .{};
 
-    const object_name_len = mem.alignForward(usize, object_name.len + 1, ptrWidth(format));
+    const object_name_start = writer.end + @sizeOf(ar_hdr);
+    const object_start = mem.alignForward(usize, object_name_start + object_name.len + 1, 8);
+    const object_name_len = object_start - object_name_start;
     const total_object_size = object_size + object_name_len;
 
     {
@@ -193,7 +194,7 @@ pub const ArSymtab = struct {
     pub fn write(ar: ArSymtab, format: Format, macho_file: *MachO, writer: *Writer) !void {
         const ptr_width = ptrWidth(format);
         // Header
-        try writeHeader(SYMDEF, ar.size(format), format, writer);
+        try writeHeader(SYMDEF, ar.size(format), writer);
         // Symtab size
         try writeInt(format, ar.entries.items.len * 2 * ptr_width, writer);
         // Symtab entries
diff --git a/src/link/MachO/Object.zig b/src/link/MachO/Object.zig
index cff42a447e090ed2e88c763a49023762f9dd1275..17b7e5e768f22ebebc22c0fecaab13eba95f59b7 100644
--- a/src/link/MachO/Object.zig
+++ b/src/link/MachO/Object.zig
@@ -1805,11 +1805,11 @@ pub fn updateArSize(self: *Object, macho_file: *MachO) !void {
     };
 }
 
-pub fn writeAr(self: Object, ar_format: Archive.Format, macho_file: *MachO, writer: *Writer) !void {
+pub fn writeAr(self: Object, macho_file: *MachO, writer: *Writer) !void {
     // Header
     const size = try macho_file.cast(usize, self.output_ar_state.size);
     const basename = std.fs.path.basename(self.path);
-    try Archive.writeHeader(basename, size, ar_format, writer);
+    try Archive.writeHeader(basename, size, writer);
     // Data
     const file = macho_file.getFileHandle(self.file_handle);
     // TODO try using copyRangeAll
diff --git a/src/link/MachO/ZigObject.zig b/src/link/MachO/ZigObject.zig
index fc2500867f7d90d619c91fd0b2ad48bc3c59f9d1..6b69c2df05e692704acc961ac8b55a55c10fe7aa 100644
--- a/src/link/MachO/ZigObject.zig
+++ b/src/link/MachO/ZigObject.zig
@@ -322,10 +322,10 @@ pub fn updateArSize(self: *ZigObject) void {
     self.output_ar_state.size = self.data.items.len;
 }
 
-pub fn writeAr(self: ZigObject, ar_format: Archive.Format, writer: anytype) !void {
+pub fn writeAr(self: ZigObject, writer: anytype) !void {
     // Header
     const size = std.math.cast(usize, self.output_ar_state.size) orelse return error.Overflow;
-    try Archive.writeHeader(self.basename, size, ar_format, writer);
+    try Archive.writeHeader(self.basename, size, writer);
     // Data
     try writer.writeAll(self.data.items);
 }
diff --git a/src/link/MachO/file.zig b/src/link/MachO/file.zig
index 4f6f70debeef007b915bfeb07d5317b87fffabc2..ddd308ee2092e6e20c291468cf6373924bd85731 100644
--- a/src/link/MachO/file.zig
+++ b/src/link/MachO/file.zig
@@ -322,11 +322,11 @@ pub const File = union(enum) {
         };
     }
 
-    pub fn writeAr(file: File, ar_format: Archive.Format, macho_file: *MachO, writer: anytype) !void {
+    pub fn writeAr(file: File, macho_file: *MachO, writer: anytype) !void {
         return switch (file) {
             .dylib, .internal => unreachable,
-            .zig_object => |x| x.writeAr(ar_format, writer),
-            .object => |x| x.writeAr(ar_format, macho_file, writer),
+            .zig_object => |x| x.writeAr(writer),
+            .object => |x| x.writeAr(macho_file, writer),
         };
     }
 
diff --git a/src/link/MachO/relocatable.zig b/src/link/MachO/relocatable.zig
index b864ee66ca42394529dd6c58556e5cb10801e413..793cfe5f0c2659a7df45a6ea69dfccc0f101db08 100644
--- a/src/link/MachO/relocatable.zig
+++ b/src/link/MachO/relocatable.zig
@@ -149,7 +149,6 @@ pub fn flushStaticLib(macho_file: *MachO, comp: *Compilation, module_obj_path: ?
     for (macho_file.objects.items) |index| files.appendAssumeCapacity(index);
 
     const format: Archive.Format = .p32;
-    const ptr_width = Archive.ptrWidth(format);
 
     // Update ar symtab from parsed objects
     var ar_symtab: Archive.ArSymtab = .{};
@@ -171,7 +170,8 @@ pub fn flushStaticLib(macho_file: *MachO, comp: *Compilation, module_obj_path: ?
     const total_size: usize = blk: {
         var pos: usize = Archive.SARMAG;
         pos += @sizeOf(Archive.ar_hdr);
-        pos += mem.alignForward(usize, Archive.SYMDEF.len + 1, ptr_width);
+        pos += Archive.SYMDEF.len + 1;
+        pos = mem.alignForward(usize, pos, 8);
         pos += ar_symtab.size(format);
 
         for (files.items) |index| {
@@ -182,7 +182,8 @@ pub fn flushStaticLib(macho_file: *MachO, comp: *Compilation, module_obj_path: ?
                     pos = mem.alignForward(usize, pos, 2);
                     state.file_off = pos;
                     pos += @sizeOf(Archive.ar_hdr);
-                    pos += mem.alignForward(usize, zo.basename.len + 1, ptr_width);
+                    pos += zo.basename.len + 1;
+                    pos = mem.alignForward(usize, pos, 8);
                     pos += try macho_file.cast(usize, state.size);
                 },
                 .object => |o| {
@@ -190,7 +191,8 @@ pub fn flushStaticLib(macho_file: *MachO, comp: *Compilation, module_obj_path: ?
                     pos = mem.alignForward(usize, pos, 2);
                     state.file_off = pos;
                     pos += @sizeOf(Archive.ar_hdr);
-                    pos += mem.alignForward(usize, std.fs.path.basename(o.path).len + 1, ptr_width);
+                    pos += std.fs.path.basename(o.path).len + 1;
+                    pos = mem.alignForward(usize, pos, 8);
                     pos += try macho_file.cast(usize, state.size);
                 },
                 else => unreachable,
@@ -222,7 +224,7 @@ pub fn flushStaticLib(macho_file: *MachO, comp: *Compilation, module_obj_path: ?
         if (padding > 0) {
             writer.splatByteAll(0, padding) catch unreachable;
         }
-        macho_file.getFile(index).?.writeAr(format, macho_file, &writer) catch |err|
+        macho_file.getFile(index).?.writeAr(macho_file, &writer) catch |err|
             return diags.fail("failed to write archive: {t}", .{err});
     }