In short
Until then, you can't withdraw the offer.
On busy offer nights it might be just a few hours.
How it works in Ontario
Every standard Ontario Agreement of Purchase and Sale has an irrevocability clause. It names who the offer is irrevocable by, the buyer or the seller, and the exact time and date it stays open.
Until that time, the person who made the offer has agreed not to withdraw it. The other side can accept, reject or counter.
If the offer isn't accepted by that time, the standard wording says it becomes null and void and the deposit goes back to the buyer in full, without interest.
The deadline is written as a specific time and date, such as 11:59 p.m. on a named day. Both sides should read the latest version carefully, because a typo in the date or time can cause real confusion.
Counter-offers flip the clock
When the seller signs back a counter-offer, the irrevocability usually switches to the seller with a new deadline. Now the buyer is the one deciding before time runs out.
Each round of a negotiation can have its own irrevocable time, so watch the latest version closely.
How long should it be?
There is no set length. On a scheduled offer night it might be a few hours. On a quieter listing it could be a day or more.
A short deadline keeps pressure on the seller. A pre-emptive or bully offer often uses a very short one to push for a decision before the offer date. A longer one gives the seller room, which can help if they need to consult someone.
Before you set it, ask the seller's agent how and when the seller plans to review offers.
Acceptance has to reach you in time
An agreement is generally formed when the signed acceptance is communicated back before the irrevocable time. A signature alone, sent after the deadline, may not be enough.
If timing is tight or something goes wrong, speak to your lawyer before treating the deal as done or dead.
Common questions about irrevocable date
What does irrevocable mean on an offer in Ontario?
It means the offer can't be withdrawn until the time and date written in the irrevocability clause. Until then, the other side can accept, reject or counter. If it isn't accepted by that time, the offer becomes null and void and the deposit is returned in full.
Can I withdraw my offer before the irrevocable time?
Under the standard Ontario agreement, you agree not to withdraw the offer before the irrevocable time. Trying to pull an offer early can raise legal questions, so speak to your lawyer before attempting it. That's why it pays to set the time deliberately when you write the offer.
How long should an irrevocable date be?
There is no required length; it's a negotiating choice. On busy offer nights it may be a few hours, while on a quieter listing a day or more is common. Shorter keeps pressure on; longer gives the other side time to decide.
What happens when the irrevocable time passes?
If the offer hasn't been accepted by then, it expires and becomes null and void under the standard form. The deposit, if already given, is returned to the buyer without interest. You are free to make a new offer or move on.
Sources
General information for Ontario, updated October 2026. Not legal, tax or mortgage advice. Rules change, so confirm with your lawyer, lender or the source above before you rely on it.