Tax on a used car in Ontario, explained

The tax line is where a lot of used-car buyers get an unpleasant surprise at ServiceOntario — often because they assumed they’d pay tax on the price they negotiated, and they don’t. Here’s how it actually works.

Private sale: 13% on the wholesale value

When you buy from another person privately in Ontario, you pay 13% retail sales tax (RST)when you register the vehicle in your name. The catch is what that 13% is calculated on: it’s the greater of the purchase price or the vehicle’s wholesale value. The province uses a standard valuation (the Canadian Red Book) to set that wholesale figure.

In plain terms: if you negotiate a great deal well below book value, you still pay tax on the book value, not your low price. If you overpay, you pay tax on your price. The province is protecting itself against people writing “$500” on a bill of sale to dodge tax.

The appraisal exception

There’s an out for cars genuinely worth less than book — a high-mileage, damaged, or rough vehicle. If you get a signed appraisal from a qualified appraiser (or, for older vehicles, use the applicable process) showing the car is worth less than the wholesale value, tax can be based on the higher of your purchase price or the appraised value instead. Worth it when the gap is large; not worth the hassle for a small difference.

Family gifts

A vehicle transferred as a gift between certain close family members can be exemptfrom the tax, provided you complete a sworn statement for a family gift. The eligible relationships are specific (spouse, parent, child, sibling, grandparent, and similar), so confirm your situation qualifies before assuming it’s tax-free.

Buying from a dealer is different

Buy the same used car from a registered dealer and the tax works the normal way: you pay 13% HST on the actual selling price, not the Red Book value. Dealers also handle the tax and paperwork as part of the sale. That difference — price-based at a dealer, value-based privately — is one reason a private deal isn’t always as much cheaper as the sticker gap suggests once tax is in.

Estimate it before you negotiate

Knowing the tax in advance changes how you negotiate — it’s real money on top of the price. Use our calculator to estimate the 13% on the greater of your price or the wholesale value before you sit down with a seller.

The bottom line

On a private Ontario sale, budget 13% of the wholesale value, not your negotiated price, unless you have an appraisal or a family-gift exemption. Tax rules and valuations change, so confirm the current rate and process with ServiceOntario or the Ministry of Finance before you register.