Given　the　global　emphasis　on　sustainable　development,　the　construction　industry　is　increasingly　prioritising　advancements　in　building　circularity　(BC).　This　study　conducted　a　comparative　analysis　on　BC　of　multi-storey　reinforced　concrete　(RC)　and　timber　frame　structural　systems:　developing　two　digital　models,　a　RC　structure　utilising　conventional　materials　and　a　timber　structure　employing　wood-based　materials;　performing　structural　analysis　in　Midas　Gen　to　establish　comparable　foundations;　and　quantitatively　assessing　the　circularity　performances　of　the　two　structure　types　across　four　levels:　materials,　elements,　systems　and　the　building　as　a　whole.　The　results　highlighted　the　significant　advantages　of　wood-based　materials　in　enhancing　BC　at　specific　levels.　This　study　offers　architects　and　practitioners　new　perspectives　and　theoretical　foundations　for　design　decisions　and　material　selection.　©　(2025)　WORLD　CONFERENCE　ON　TIMBER　ENGINEERING　2025　(WCTE　2025)　All　rights　reserved.