diff --git a/src/link/MachO/Archive.zig b/src/link/MachO/Archive.zig
index a65531064d8ae1e866487151a294f6132bfe7a50..aba31d17424f5c59227be9fcd6457b38136d41e3 100644
--- a/src/link/MachO/Archive.zig
+++ b/src/link/MachO/Archive.zig
@@ -231,7 +231,7 @@ pub const ArSymtab = struct {
             try writeInt(format, file_off, writer);
         }
         // Strtab size
-        const strtab_size = mem.alignForward(u64, ar.strtab.buffer.items.len, ptr_width);
+        const strtab_size = mem.alignForward(usize, ar.strtab.buffer.items.len, ptr_width);
         const padding = strtab_size - ar.strtab.buffer.items.len;
         try writeInt(format, strtab_size, writer);
         // Strtab