T2125 explained, line by line.

What the T2125 is, and who files it

If you run a business under your own name, even a side hustle, the CRA sees it as self-employment, and you report it on Form T2125 with your personal return. That covers dog walkers, pet sitters, tutors, cleaners, detailers and most gig work. You fill in one T2125 per business; a tutor who also walks dogs files two.

The line numbers below come from the current version of the form, T2125 E (25), and the CRA's guide T4002, both checked in September 2026. The CRA publishes the 2026 version of the form early in 2027; line numbers rarely change between years, but check the new form before you file.

Part 1: Identification

Your name, SIN, business name (if you use one) and address. The lines that trip people up:

• Fiscal period. Self-employed individuals generally use a December 31 year-end, so for 2026 enter January 1 to December 31, 2026 (or the day you started, if later).
• Business number. Only if you have one, for example because you registered for GST/HST. Many small side businesses don't.
• Accounting method. Business income has to be reported on the accrual method: income counts when you earn it, not when the client pays. Only commission agents, farmers and fishers can use the cash method. For a dog walker paid weekly, the difference is usually just the invoices open at year-end.
• Industry code. A six-digit NAICS code for your main activity.

Industry codes for common service businesses

Codes from Statistics Canada's NAICS Canada 2022 Version 1.0, checked September 2026: 812910 lists dog walking and pet sitting, 611690 lists private tutors, and 561722 lists residential and maid cleaning. If you file online, your tax software supplies the code list, and the CRA asks you to use that.

Part 2: Internet business activities

If clients find or book you through a website, a booking page or a marketplace profile that brings in income, enter how many sites, up to five addresses, and roughly what percentage of your income came through them. An estimate is fine.

Part 3: Your income

Service businesses fill in Part 3A (business income). Part 3B is for professional income (accountants, lawyers, some consultants).

• Amount 3A, gross sales, commissions or fees: everything you billed for the year, including any GST/HST you collected.
• Amount 3B: the GST/HST (and PST) included in 3A, plus returns, discounts and refunds.
• Amounts 3D to 3F: only if you use the GST/HST quick method. The GST/HST you collected minus what you remitted counts as income.
• Line 8000, adjusted gross sales: 3C plus 3F.
• Line 8230, other income: for example a bad debt you'd written off that a client finally paid. Quick-method users also report the 1% credit here.
• Line 8299, gross business income: the total. It also goes on line 13499 of your return.

Does gross income include GST/HST?

Not in the end. If you're a small supplier (under $30,000 of taxable sales in a single calendar quarter and over the last four consecutive calendar quarters) and haven't registered, you charged no GST/HST, so 3A and 3C are the same number. Once you're a registrant, you include the GST/HST in 3A and take it back out at 3B, because it's the government's money, not income. The GST/HST guide covers the threshold, registering, and the quick method.

Part 3D (cost of goods sold) is for businesses that buy or make goods to resell. A service business usually skips it and uses line 8299 as the starting point for Part 4.

Where your gross income number comes from

Add up every payment for work done in the year: e-Transfers, card payments, cash and cheques. This is the part Biller helps with. Biller records the payments you receive (each Autodeposit e-Transfer from the notification emails you forward, card payments through your Stripe account, and cash or cheques you enter), and shows your totals by client and by quarter. On Pro, the year-end export gives those totals as a CSV for you or your accountant. It's a starting point for amount 3A, not a filled-in form: Biller doesn't track expenses, and it doesn't prepare your T2125.

Part 4: Expenses

Enter only the business part of each expense, and don't include GST/HST you're claiming back as an input tax credit. These are the lines a one-person service business actually uses:

The total goes on line 9368, and line 9369 is your net income before adjustments: line 8299 minus line 9368. Keep every receipt: the CRA can ask to see them, and you don't send them with the return.

Vehicle expenses (line 9281)

If you drive between clients, the business share of your car costs is deductible. Fill in Chart A on the form: total kilometres, business kilometres, and your fuel, insurance, licence, repairs, interest or lease costs. The business share is business kilometres divided by total kilometres.

The CRA expects a logbook: date, destination, purpose and kilometres for each business trip, plus your odometer at the start and end of the year. After one full year of logbook, you can keep a sample logbook for three months in later years, as long as your business use stays within 10% of the base year. Depreciation on the car itself is CCA, on line 9936, not line 9281.

Capital cost allowance (line 9936), briefly

Things that last, such as a laptop, a pressure washer or a vehicle, aren't deducted all at once. You claim a percentage each year through CCA, by class: for example Class 8 (most equipment) at 20%, Class 10 (most vehicles) at 30%, and Class 50 (computers) at 55%. In the year you buy something, the half-year rule usually limits the claim to half, though some recent purchases qualify for a bigger first-year claim. The rules change often; the CCA chapter of Guide T4002 has the current ones, and this is a good place to ask an accountant.

Part 5: Your net income, and the home office

For a sole proprietor, amount 5A is simply line 9369. Partnership lines (9974, 9943) don't apply to you. Then:

• Line 9945, business-use-of-home expenses. Worked out on the form's "Calculating business-use-of-home expenses" chart (Part 7).
• Line 9946, your net income (loss). This goes on line 13500 of your return (or 13700 for professional income).

Home office: the two conditions

You can claim part of your home costs only if the workspace is either:

1. your principal place of business, which is common for tutors teaching at home and for anyone who runs the business from a desk at home, or
2. used only to earn business income and used regularly to meet clients.

Claim the business share of rent (or mortgage interest and property tax, if you own), heat, electricity, home insurance and maintenance, usually based on the workspace's share of your home's area. If the room is also used personally, reduce it again by the hours used for business. The claim can't create or increase a business loss. Anything you can't use carries forward to next year.

Where the T2125 lands on your tax return

Line numbers from Form T2125 E (25) and the CRA's line pages for 22200, 31000 and 42100, checked September 2026.

CPP on self-employment (Schedule 8)

This is the cost most first-year sole proprietors don't see coming. With no employer to match your contributions, you pay both halves. For 2026 that's 11.9% of net self-employment earnings between $3,500 and $74,600 (up to $8,460.90), plus 8% CPP2 on earnings between $74,600 and $85,000 (up to $832), according to the CRA's 2026 CPP rates. On $40,000 of profit, that's ($40,000 − $3,500) × 11.9% = $4,343.50.

Part of it comes back: the "employer" half and the enhanced part of your half are a deduction (line 22200), and the rest earns a tax credit (line 31000). If you also have a job, the CPP deducted from your pay counts toward the same yearly maximum. In Quebec you pay QPP instead, at 12.6% for both halves. To see what your profit costs in tax and CPP together, try the self-employed tax calculator.

Deadlines and instalments for the 2026 tax year

• April 30, 2027: pay any balance owing for 2026. Interest starts after this date, even if you file later.
• June 15, 2027: file your 2026 return with the T2125, if you or your spouse or common-law partner had self-employment income.
• Instalments: if your net tax owing is more than $3,000 in 2026 and was also more than $3,000 in 2025 or 2024 ($1,800 in Quebec), the CRA expects quarterly payments on March 15, June 15, September 15 and December 15. The CRA usually sends an instalment reminder with the amount.

Dates from the CRA's T4002 chapter 1 (which gives June 15 and April 30 as the filing and payment dates) and its instalment rules, checked September 2026. When a date falls on a weekend or holiday, you have until the next business day.

A year-round habit that makes the T2125 easy

1. Invoice every job, even regulars paying by e-Transfer. Your invoices are the record behind amount 3A.
2. Keep one account for the business so expenses are easy to find, and photograph receipts as you go.
3. Keep a mileage log from January 1 if you drive between clients.
4. Set aside tax as you're paid. About 25% of profit covers income tax and CPP for many one-person businesses; the calculator gives your number.
5. Charge enough to cover it. Tax and CPP come out of your rate. The pricing guides show what Canadian service businesses charge.

Common questions

What is Form T2125?

Form T2125, Statement of Business or Professional Activities, is the CRA form a sole proprietor uses to report business income and expenses. You file it with your personal income tax return, and the net income on line 9946 goes onto line 13500 of your return. You fill in a separate T2125 for each business you run.

Who has to file a T2125?

Anyone who earns business or professional income as a sole proprietor or partner: dog walkers, tutors, cleaners, freelancers, gig workers and side hustlers. It doesn't matter if the business is small or a side job. If your business is incorporated, you file a corporate T2 return instead.

What is the industry code for a dog walker or pet sitter on the T2125?

812910, Pet care (except veterinary) services, which Statistics Canada's NAICS 2022 lists as covering dog walking and pet sitting. Tutors usually use 611690 and house cleaners 561722. If you file online, pick the code from your tax software's list.

Do I include GST/HST in gross income on the T2125?

You enter your sales including any GST/HST you collected at amount 3A, then subtract the GST/HST at amount 3B, so it doesn't count as income. If you use the quick method, the difference between the GST/HST you collected and what you remitted is added back as income. If you are a small supplier and not registered, you collected no GST/HST, so there is nothing to subtract.

Can I claim my home office on the T2125?

Yes, on line 9945, if the workspace is your principal place of business, or you use it only for the business and regularly meet clients there. You claim the business share of rent or mortgage interest, utilities, insurance and property tax. The claim can't create or increase a business loss; unused amounts carry forward to next year.

When is the T2125 due for the 2026 tax year?

It goes in with your 2026 return, which self-employed people can file until June 15, 2027. Any tax you owe is still due by April 30, 2027, so work out your balance before the end of April.

Does Biller fill in the T2125 for me?

No. Biller doesn't fill in tax forms or track expenses. What it gives you is your income side: the payments you recorded, by client and by quarter, and on Pro a year-end CSV export of those totals for you or your accountant. That is a starting point for your gross sales at amount 3A.

Related guides

• Self-employed tax calculator for Canada (2026)
• GST/HST guide for small businesses
• Pricing guides by service
• Side hustles in Canada and what they pay
• Free invoice generator