June 15, 2026 Self-Employed Filing Deadline: Quarterly Instalments, GST/HST Registration, and Tax Buffer Planning

If you ran a business in 2025 or earned any self-employment income (freelance, consulting, gig work, side hustle), your T1 return is due June 15, 2026, not April 30. But there’s a catch most self-employed Canadians learn the hard way: the tax owing was still due April 30. If you didn’t pay by then, the CRA is accruing daily interest at the prescribed overdue rate (7% annually for Q2 2026, compounded daily).

This guide walks through the three calculators every self-employed Canadian needs before June 15 closes, and how to wire them together into a single discipline.

1. Are You Required to Pay Quarterly Instalments?

Under ITA s.156.1, CRA requires quarterly tax instalments if both of these are true:

• Your current-year net tax owing will exceed $3,000 ($1,800 if you live in Quebec because Revenu Québec administers Quebec provincial tax separately).
• Either your prior-year net tax owing or your two-years-prior net tax owing also exceeded the threshold.

If you missed an instalment this year, CRA charges interest from each missed due date — and if total instalment interest exceeds $1,000, an additional 50% penalty applies under s.163.1.

There are three permitted methods:

Method	Quarterly amount	When to choose it
No-calculation (CRA reminder)	First 2 = ¼ of two-years-prior tax; last 2 = balance of prior-year	Default — only method that guarantees no interest if paid on time
Prior-year option	¼ of prior-year net tax owing each quarter	If you didn’t get a CRA reminder or no-calc is higher than prior-year
Current-year option	¼ of your estimated current-year tax	If your income dropped vs prior year, but you bear the risk of under-estimating

Run your numbers through the CRA Quarterly Tax Instalments Calculator to see all three methods side by side, plus an estimate of the interest + penalty cost if you skip all four payments.

2. Do You Need to Register for GST/HST?

If your taxable worldwide supplies exceed $30,000 in any single calendar quarter or in any four consecutive calendar quarters (rolling), you cease to be a “small supplier” under ETA s.148 and must register within 30 days.

The rolling-4-quarter test catches most freelancers as their income grows: even at $7,501 per quarter, the rolling sum hits $30,004 and you’re over.

There are also reasons to register voluntarily before you cross the threshold:

• B2B suppliers generally benefit. Your business customers recover the GST/HST you charge via their own Input Tax Credits, so charging tax doesn’t reduce demand. Meanwhile, you recover GST/HST paid on every business input — laptops, software, professional fees, your home office’s share of utilities.
• B2C suppliers face a tougher trade-off. Individual customers cannot recover the tax, so registration is effectively a 5%-15% price increase. Voluntary registration only pays off if your ITC recovery exceeds the price elasticity hit plus admin overhead (typically $500-$1,500/year).

The GST/HST Registration Threshold Calculator tracks your last 5 quarters of revenue, flags single-quarter or rolling breaches, and estimates the voluntary-registration ROI given your customer mix — plus a Quick Method preview if you’re eligible (annual tax-included revenue under $400,000).

3. How Much Should You Sweep Each Month?

CRA doesn’t withhold from your freelance payments the way an employer does. Without a disciplined monthly sweep, the combined federal + provincial income tax + 11.9% CPP + GST/HST remittance can quietly hit 35-45% of revenue and surprise you at filing.

The reliable approach: every time a client payment lands, immediately move a fixed percentage to a separate high-interest savings account. Don’t touch it until each CRA deadline:

• Mar 15 / Jun 15 / Sep 15 / Dec 15 — quarterly income tax instalments
• Monthly / quarterly / annually — GST/HST remittance based on your filing frequency
• April 30 next year — balance due (filing deadline is June 15 for self-employed, but tax is due April 30)

The Self-Employed Tax Buffer Calculator takes your expected annual net profit, province, and GST/HST status, and gives you a single number: the percentage of every dollar earned that should leave your operating account. It breaks down the math by federal income tax, provincial income tax, CPP1 (up to YMPE), CPP2 (above YMPE), GST/HST net remitted, and a configurable safety margin.

Wiring the Three Together

The three calculators work as a sequence:

1. Tax buffer sets your monthly discipline. As cash comes in, sweep this percentage.
2. Quarterly instalments consume the buffer four times a year. Match the amount to whichever CRA-permitted method is lowest.
3. GST/HST registration kicks in when the rolling threshold is crossed. Once registered, the buffer rate goes up to cover the net remittance, and the GST/HST filing frequency adds 1-12 more deadlines a year.

If you’ve been freelancing for less than a year and your income is under $30K, you can skip step 3 and treat step 1 as your only discipline. As revenue grows, the discipline scales with you.

CRA Penalties for Late June 15 Filing

The filing extension to June 15 is a deadline for the return — not for the tax. If you owe tax and didn’t pay by April 30:

• Daily interest at 7% (Q2 2026 prescribed overdue rate), compounded daily, starting May 1.
• Late-filing penalty of 5% of the balance owing plus 1% per full month late, capped at 12 months, if you also file the return after June 15 — see the CRA late-filing penalty calculator for the exact dollar cost.
• Repeat-offence penalty doubles to 10% flat + 2% per month if you were also late in any of the previous three years.

The cleanest way to avoid all of this: have the tax owing paid by April 30 even though your return isn’t due until June 15.

What Counts as “Self-Employment Income”?

CRA’s definition is broad. Include all of:

• Freelance income from clients (whether you invoiced through a corporation or as a sole proprietor)
• Gig work (Uber, Lyft, SkipTheDishes, Doordash, Instacart, TaskRabbit, etc.)
• Online platform income (Etsy, eBay, Facebook Marketplace, Amazon FBA, OnlyFans, Substack)
• Side hustles (tutoring, cleaning, photography, web design)
• Income from a personal services business (PSB) — even if billed through a CCPC, special rules apply
• Investment income from a business you actively manage (e.g., a flipping operation)

Most platforms now issue T4A or T2125-equivalent slips automatically. CRA cross-references these against your return — under-reporting platform income is the fastest path to a desk audit.

The Three Calculators

• CRA Quarterly Tax Instalments Calculator — Are you required? How much per quarter? What’s the penalty if you skip?
• GST/HST Registration Threshold Calculator — Are you still a small supplier? Should you register voluntarily?
• Self-Employed Tax Buffer Calculator — What percentage of every dollar should you sweep into a tax savings account?

If you’ve put off this work because June 15 felt far away, the time to set up the discipline is now — not the night before.