Should I Separate GST from Income?
If you are GST registered, GST collected is not the same as spendable income. The buffer app treats GST as a separate bucket so the reserve rule reflects what is actually yours after tax obligations.
Why GST should not sit in the same pile as income
When GST is mixed into day-to-day spending, it is easier to overestimate what is safe to keep. Separating it forces a cleaner view of net revenue, tax reserves, and actual spendable cash.
How the buffer app handles it
The app estimates a GST bucket after eligible expense credits, then layers income tax and optional super on top. That keeps the reserve rule closer to how cash pressure actually feels across a year.
Next steps
Use the Buffer app when you want the dollars-per-100 rule. Use the BAS Calculator when you want statement-style GST and PAYG detail.