(Replace B50 with the cell where you input your income amount)
From August 2024 - present
=IF(B50<=15600, B50*10.5%, IF(B50<=53500, (B50-15600)*17.5%+1638, IF(B50<=78100, (B50-53500)*30%+7075.5, IF(B50<=180000, (B50-78100)*33%+15060.5, (B50-180000)*39%+49747.5))))
Up to end of July 2024
=IF(B50<=14000, B50*10.5%, IF(B50<=48000, (B50-14000)*17.5%+1470, IF(B50<=70000, (B50-48000)*30%+7420, IF(B50<=180000, (B50-70000)*33%+14020, (B50-180000)*39%+50320))))
Disclaimer:
Use this as is at your own risk.