Most advice out there is written for someone doing one thing. You are selling a home and buying another, and the hard part sits in the gap between them. This page is about that gap: what your sale leaves you, what that buys, and which order to do it in.
Nearly all of your down payment is sitting in the home you already own, and you cannot see it until you know what selling costs you. Work that out first. Everything else follows from it.
Commission is negotiable on every transaction and there is no standard rate, so there is no number filled in for you here. Put in what you have agreed to, or expect to, along with legal fees and any prep work. Ask me and I will give you a straight figure for your situation.
Estimates for planning, not a pre-approval. Your lender decides what you can borrow, and a real home value needs someone to look at your actual house.
There is no answer that is right for everyone, and anyone who gives you one without asking about the market is guessing. In a slower market, selling first protects you, because you know exactly what you have before you commit to anything. In a fast market with little inventory, selling first can leave you with nowhere to go.
Buying first usually means bridge financing, and most Ottawa lenders will not approve that until your sale is firm. So buying first is often not available as early as people expect it to be. The other route is an offer conditional on your sale, which is weaker when you are competing against clean offers.
You pay on both sides, and the second set of costs catches people out. On the sale: commission, your lawyer, any prep work, and the payout of your existing mortgage. On the purchase: land transfer tax, another set of legal fees, the inspection, adjustments, and the move itself.
Land transfer tax is usually the largest single line, and it is worth knowing that the first-time buyer rebate does not apply to you. You pay it in full. On an $800,000 purchase in Ottawa that is $12,475, which for one recent client was most of what the whole move cost them.
Ask your lender for two numbers in writing before you list, because the gap between them is often large. Porting moves your current mortgage to the new property, so you keep your rate and pay no penalty, but it only works if your lender allows it, if you still qualify, and if the two closings fall inside the window they give you.
Breaking instead means a prepayment charge. On a fixed mortgage that is usually the greater of three months of interest or the interest rate differential, and it can run into thousands.
The order, the timing and the numbers all depend on each other, and they are far easier to sort out in a conversation than on a spreadsheet. Tell me what you own and what you are hoping to move into, and I will tell you what I would do.