Live math canvas
At 20% VAT/GST, 120.00 entered as net price gives net 120.00, tax 24.00, and gross 144.00.
Formula applied
CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.
Add GST: GST = amount x 10%, total = amount x 1.10. Remove GST: GST = amount - amount / 1.10, exclusive amount = amount / 1.10.Your live breakdown
These values come from the controls above and update when the calculator changes.
Resulting answer
Mode: net price. Net 120.00; tax 24.00 at 20%; gross 144.00.
Assumptions used
The visible assumptions define the boundary of this calculation.
Master’s Tip
Professional note: print the input values, formula, result and date together so the calculation can be reviewed later.
Printable record
These rows are ready for a report, worksheet, quote note or audit trail.
Add GST: GST = amount x 10%, total = amount x 1.10. Remove GST: GST = amount - amount / 1.10, exclusive amount = amount / 1.10.
Adding GST to $100 gives $10 GST and a $110 total. Removing GST from $110 gives $10 GST and $100 before GST.
Professional note: print the input values, formula, result and date together so the calculation can be reviewed later.
Basis: Australian GST at 10%. Some supplies are GST-free or input taxed, so confirm treatment with ATO guidance or an adviser.
GST proof
GST-inclusive and GST-exclusive prices use different arithmetic. The page states whether it is adding GST to a net amount or extracting the GST component from an inclusive amount.
Visible checks
Methodology & Accuracy
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Add GST: GST = amount x 10%, total = amount x 1.10. Remove GST: GST = amount - amount / 1.10, exclusive amount = amount / 1.10.
Basis: Australian GST at 10%. Some supplies are GST-free or input taxed, so confirm treatment with ATO guidance or an adviser.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Professional note: print the input values, formula, result and date together so the calculation can be reviewed later.
The GST calculator adds 10% GST to an Australian price or extracts the GST component from a GST-inclusive price.
No. Use it as a transparent planning estimate, then verify the current rule, rate, contract or official source for the decision you are making.