Calculate a Cash Reserve for Side-Income Tax
Enter monthly side-income revenue, supported costs and a reserve percentage. The tool separates profit from receipts, annualises the profit and shows cash remaining after the reserve transfer.
Protect side-income cash before tax review
The default example reserves 20 percent of $3,000 monthly side-income profit.
- Monthly profit before personal tax
- $3,000
- Annualised profit
- $36,000
- Monthly profit after reserve transfer
- $2,400
Protect cash before annual tax reconciliation
Calculate a side-income tax cash reserve from monthly revenue, supported business costs and an editable planning percentage.
Estimate the combined annual position with the income-tax estimator and follow the evidence process in the side-income reserve guide.
Reserve from profit, not gross receipts
Separate supported source costs
A receipt and taxable profit are not automatically the same amount.
Recalculate during the year
Income, costs, reliefs and tax already paid can change the required buffer.
- Calculation method
- Monthly revenue minus costs, multiplied by the chosen reserve percentage.
- Best used for
- Cash-flow planning between income-tax reviews for freelance or other side income.
- Keep outside the result
- Actual tax liability, relief eligibility, loss treatment, instalments and final filing amounts.
Keep the source ledger intact
Revenue, costs, invoices and receipts should remain traceable even when one monthly profit total is used for planning.
Choose a buffer from the combined position
Employment income, other sources, reliefs and tax already paid can move the eventual marginal effect.
Reconcile and release excess carefully
Update the estimate quarterly and only release excess reserve after supported tax and payment figures are reviewed.
Protect side-income cash before tax review in a worked example
The default example reserves 20 percent of $3,000 monthly side-income profit. Supported source costs are removed from monthly receipts before the chosen reserve percentage is applied. The transfer protects cash but does not establish final tax. Recalculate with combined annual income, reliefs and tax already paid, then reconcile the reserve after filing.
- Monthly side-income revenue
- $4000
- Monthly supported source costs
- $1000
- Planning reserve percentage
- 20 %
Suggested monthly cash reserve: $600
Replace the planning percentage with a full-year estimate and actual filing records when available.
- Monthly profit before personal tax
- $3,000
- Annualised profit
- $36,000
- Monthly profit after reserve transfer
- $2,400
Calculation rule: Monthly revenue minus costs, multiplied by the chosen reserve percentage. Boundary: Actual tax liability, relief eligibility, loss treatment, instalments and final filing amounts.
Side-income reserve questions
Is the reserve percentage an official tax rate?
No. It is a user-controlled cash-planning buffer.
Should I reserve from unpaid invoices?
Use a separate accrual view if needed, but cash reserves normally require cash actually received.
Does the tool file or pay tax?
No. It only separates planning cash.
Connect source records to the annual tax position
Connect taxable income, planning rates, payroll withholding, other payments and the estimated final balance without assuming one tax system.