Free Quarterly Tax Instalment Worksheet (Canada)

Download and open in Excel or Google Sheets

Works identically in either — no macros or add-ins needed.

Enter your year-to-date net income

Pull this from your P&L or bookkeeping records for the year so far.

Review the estimated federal and provincial tax calculation

This gives you a general estimate of what’s likely owed for the year.

Divide into the appropriate quarterly instalment

Adjust for what you’ve already paid in prior instalments this year.

Run the built-in AI prompt to sanity-check it

Attach the saved file to ChatGPT or Claude and ask if the estimate looks reasonable — but confirm the actual figure with a tax professional or CRA’s own instalment reminders.

Skipping instalments CRA has requested

This is one of the most common ways instalment interest charges happen — even an imperfect estimate paid on time is usually better than skipping it.

Ignoring CRA’s own instalment reminder amounts

CRA sends instalment reminders based on your prior year’s tax — using this option is often the simplest way to avoid interest, even if it doesn’t perfectly match current-year income.

Forgetting both federal and provincial tax

Canadian instalments typically need to cover both — this worksheet accounts for both, but it’s a common oversight in manual estimates.

Treating this worksheet as a substitute for a tax professional

This is a planning estimate, not tax advice — for anything beyond a simple, stable-income situation, work with a tax professional to confirm your actual instalment obligation.