Ontario Construction Act Deadline Calculator
A missed date can cost you a lien or the right to withhold payment. Enter a date to see the prompt payment, lien and holdback deadlines that follow from it under Ontario's Construction Act, including the changes in force since 1 January 2026.
Prompt payment deadlines
Every deadline in the payment chain runs from the day the owner receives a proper invoice. Enter that date to see who has to act, and by when.
Applies to contracts entered into on or after 1 October 2019, where the owner's procurement process also began on or after that date (s. 87.3(4)). Unpaid amounts carry interest at the Courts of Justice Act prejudgment rate, or the contract rate if higher (s. 6.9). Payment disputes can be referred to adjudication through the Ontario Dispute Adjudication for Construction Contracts (ODACC).
Lien deadlines
A lien expires 60 days after its triggering event unless you preserve it, and a preserved lien expires 90 days later unless you perfect it. Enter the dates that have happened; the earliest one that applies to you starts the clock.
Applies where the contract was entered into, and any procurement process began, on or after 1 July 2018 (s. 87.3(1)). Work supplied after the date of substantial performance carries its own lien with its own period (s. 31(4)); the dates above use the earlier deadline. Preserve a lien by registering a claim for lien on title, or, where the lien does not attach to the land, by giving the claim to the owner (s. 34). Perfect it by starting an action and registering a certificate of action (s. 36).
Annual holdback release
Since 1 January 2026, owners must release accrued holdback every year on the anniversary of the contract. Enter the date the prime contract was entered into.
For contracts entered into before 1 January 2026, the first annual release falls on the second contract anniversary after that date and covers all holdback accrued until then (s. 87.4(4)). Holdback is not released under a contract or subcontract on which a lien has been preserved or perfected and not discharged or vacated (s. 26(4), (5)). Remaining holdback is payable within 14 days after all liens have expired or been dealt with (s. 26(8)).
Facing a payment or lien problem?
We review subcontracts, payment terms and notices for Ontario contractors and trades, and help you decide what to send and when.
Request a Free 15-Minute CallThis calculator counts calendar days under Ontario's Construction Act as consolidated on 1 January 2026. It gives general information, not legal advice, and using it does not create a lawyer-client relationship. Your contract, the type of project and the facts can change these dates. If a date falls on a weekend or holiday, do not count on an extension: act before it. Nothing you enter leaves your browser.