Co-Signer or Co-Borrower: Which Is Right for Your Toronto Home?
Quick answer: A co-borrower buys the home with you: both incomes count, both names go on the mortgage and the title, and you both own it. A co-signer backs your mortgage so you can qualify, without living there, and is fully on the hook if you stop paying. A co-borrower usually adds more buying power. In Toronto there’s a second question: who goes on title. A parent who has owned a home and takes a 50% share can cut your first-time land transfer tax rebates by up to $4,237.
Most Toronto first-time buyers need help to qualify, usually from a partner or a parent. Both routes can work. The one that fits depends on who will live in the home, who will own it, and how you want it to look in five years.
What does a co-borrower do?
A co-borrower applies with you and shares the loan and the home. The lender adds your incomes, counts both sets of debts, and tests the total against its limits. For an insured mortgage, housing costs can’t be more than 39% of gross income and all debts can’t be more than 44%, at the stress-test rate (CMHC).
This is the usual set-up for couples and siblings buying together. Both of you build equity, and both of you have to agree before the home is sold or refinanced.
What does a co-signer do?
A co-signer, usually a parent, lends their income and credit to your application. They don’t live in the home. If you miss payments, the lender can go to them for the full amount, and the mortgage counts against them the next time they borrow, even if you never miss a payment.
Whether a co-signer also goes on title depends on the lender. Ontario’s own refund guidance describes parents being on title “at the insistence of a bank”. That matters for the next section.
How much more can you borrow with help?
Here’s an example for a buyer earning $85,000 a year, looking at a condo with a $600 monthly fee and $350 a month for property tax and heat, with less than 20% down and no other debts. The co-borrower earns $65,000 and has no debts. The test uses the 6.64% qualifying rate: the best insured 5-year fixed we tracked as of October 20, 2026 (4.64%), plus 2%. For the full method, see how the mortgage stress test works for Toronto buyers.
| On your own | With a co-borrower | |
|---|---|---|
| Household income | $85,000 | $150,000 |
| Housing cost limit (39% a month) | $2,763 | $4,875 |
| Less tax and heat (example) | $350 | $350 |
| Less 50% of the condo fee | $300 | $300 |
| Room for the mortgage payment | $2,113 | $4,225 |
| Largest mortgage (6.64%, 25 years) | about $311,000 | about $622,000 |
The second income doubles the mortgage here because the tax, heat and condo fee don’t double. A co-signer can help in the same way. The difference is that the lender counts the co-signer’s own debts too, including the mortgage on their own home, so a parent with a large mortgage may add much less than their income suggests.
How does a co-owner affect Toronto’s land transfer tax rebates?
Toronto buyers pay two land transfer taxes, and first-time buyers can get up to $4,000 back from Ontario and up to $4,475 from the City (see Toronto closing costs). Both are cut to the first-time buyer’s share of the home (Ontario; Toronto Municipal Code, Chapter 760, § 760-60). Ontario’s own example is a parent and child buying 50/50: the child can claim at most half of the refund.
On a $650,000 Toronto condo, each tax is $9,475, so $18,950 in total:
| Who’s on title | Ontario refund | Toronto rebate | Land transfer tax you pay |
|---|---|---|---|
| You alone, first-time buyer | $4,000 | $4,475 | $10,475 |
| You and a first-time-buyer partner, 50/50 | $4,000 | $4,475 | $10,475 |
| You and a parent who has owned, 50/50 | $2,000 | $2,237.50 | $14,712.50 |
| You and a spouse who owned a home while married to you | $0 | $0 | $18,950 |
A spouse who owned a home before you were together doesn’t cost you the rebate; their share counts with yours. One who owned while you were married rules it out for both of you.
There’s a way to keep the full Ontario refund when a lender wants a parent on title only for the mortgage. If the parent gets no beneficial interest in the home, Ontario treats them as a trustee for you, as long as you send evidence, such as a letter from the bank or a trust agreement. You pay the tax at closing and claim the refund afterwards. The City’s by-law reduces its rebate to your interest in the home, so ask your lawyer how they’ll handle a parent on title in trust before you close.
When doesn’t this apply?
If you can qualify on your own, even at a lower price, you may not need either. Removing a co-signer later takes the lender’s approval and proof you can carry the mortgage alone, and that often means waiting for renewal or refinancing. If the co-signer is also on title, taking them off is a separate legal step. Your lender may also ask the co-signer to get advice from their own lawyer before signing.
A co-borrower who isn’t your partner, such as a sibling or a friend, owns their share outright. Put a written agreement in place on what happens if one of you wants to sell.
What should you do next?
Before you write an offer, run both structures against your real numbers, including who goes on title and what that does to your rebates. Changing it after closing usually means a refinance. Send me your income, your helper’s income and debts, and the price range you’re looking at, and I’ll show you both side by side. Book a 20-minute call with Joshua Tagg.
This is commentary, not legal, tax or financial advice. Figures as of October 20, 2026. Rates change daily. Land transfer tax rules are set by the Ontario Ministry of Finance and the City of Toronto; confirm your rebate with your real estate lawyer. All mortgages are subject to lender and insurer approval.
Frequently asked questions
What is the difference between a co-signer and a co-borrower?
A co-borrower buys the home with you. Their income and debts go into the application, their name goes on the mortgage and the title, and they own part of the home. A co-signer backs your mortgage so you can qualify but doesn't live there. They're fully responsible for the payments if you stop making them, and whether they go on title depends on the lender.
Does a co-borrower increase how much I can borrow?
Yes. The lender adds both incomes before applying the debt ratios. In our example, a buyer earning $85,000 qualifies for about $311,000 on a condo with a $600 monthly fee. With a co-borrower earning $65,000 and no debts, it's about $622,000, tested at the 6.64% qualifying rate over 25 years.
Does putting a parent on title affect the land transfer tax rebate in Toronto?
It can. Ontario's first-time buyer refund and Toronto's rebate are both cut to the first-time buyer's share of the home. If a parent who has owned a home takes 50%, the Ontario refund drops from $4,000 to $2,000 and the Toronto rebate from $4,475 to $2,237.50.
What if my lender wants my parent on title but they don't own any of the home?
Ontario accepts that the parent is on title as a trustee, and keeps your full refund, if the parent didn't acquire a beneficial interest and you send evidence, such as a letter from the bank or a trust agreement. You pay the tax on closing and apply for the refund afterwards. Ask your lawyer how the City treats the same set-up before you close.
Can a co-signer be removed from a mortgage later?
Only with the lender's approval, and you'll need to qualify on your own at that point. Often that means waiting for renewal or refinancing. If the co-signer is also on title, taking them off is a separate legal step, so plan the exit before you sign.