Short Tax Year Deadline Calculator
Enter the first and last day of a short tax year to see its length in days and weeks and the date the return is due, six months after the year-end as for any other year.
Written and reviewed by Sharad Gondaliya, CPA (Ontario), CPA Ontario Membership 61040184.
Last reviewed: October 27, 2026
Enter both dates and the filing date appears here.
Gondaliya CPA Professional Corporation is a registered EFILE electronic filer. Returns are prepared and transmitted in Canada. Credentials are never shared and never used offshore.
A Short Year Does Not Get a Short Deadline
The assumption worth correcting first: a shorter tax year does not come with a proportionally shorter filing window. Six months runs from the year-end whatever the length of the period behind it.
A two-month stub period and a twelve-month year both get six months from their year-end. The stub period does not get one month because it was one-sixth the length, and it does not get longer either.
Where Short Years Come From
Four situations produce one. A first tax year running from incorporation to the first year-end chosen. A change of fiscal year-end leaving a stub period at the changeover. A dissolution ending the year on its own date. An amalgamation ending a predecessor’s year the day before.
In all four the short period is a full tax year for filing purposes, needing its own return at $300.00 plus HST per tax year for a nil one.
The 53-Week Limit Applies to a First Year
A first tax year may not exceed 53 weeks, which is 371 days counted from the date of incorporation to the year-end. A later tax year may run a full twelve months, so the limit only bites on a first year or on the first year of a corporation coming out of an amalgamation.
Where the period entered here is longer than 53 weeks and it is a first year, the year-end is probably not the one on record. The 53-week first tax year checker tests that question on its own.
Four Short Years, Four Filing Dates
Each row is a real short period of the kind that turns up, with its length and the date its return falls due. The six months is the same in every row.
| Why the year is short | Period | Length | Return due |
|---|---|---|---|
| First year after incorporation | March 12, 2026 to December 31, 2026 | 295 days | June 30, 2027 |
| Stub period on a year-end change | January 1, 2027 to March 31, 2027 | 90 days | September 30, 2027 |
| Final year on dissolution | April 1, 2027 to August 20, 2027 | 142 days | February 22, 2028 |
| Predecessor year on amalgamation | January 1, 2027 to June 30, 2027 | 181 days | December 31, 2027 |
The dissolution row shows the shift at work, and it shows it twice. Six months after August 20, 2027 is February 20, 2028, a Sunday, so the date moves to the Monday — and that Monday is Family Day, so it moves again, to Tuesday February 22. The shift keeps stepping forward until it lands on a day that is open. The due date weekend and holiday shift calculator shows that step on its own.
Two year-ends in one calendar year means two returns, and each nil one is $300.00 plus HST per tax year. A stub period is never folded into the year on either side of it.
Frequently Asked Questions
Is a Short Year Filed Together With the Next Full Year?
No. It is a separate tax year and needs its own return. Two year-ends in one calendar year means two returns.
Does a Short Year Cost Less to File?
No. A nil return is $300.00 plus HST per tax year whatever the length of the period it covers.
Can a Tax Year Be Longer Than Twelve Months?
A first tax year may not exceed 53 weeks, which is 371 days. Later years run to the fiscal year-end on record.
What Makes a Period a Stub Period?
A change of fiscal year-end leaves a gap between the old year-end and the new one. That gap is a tax year of its own.
Does the Filing Date Still Move for a Weekend?
Yes. The shift applies to a short year exactly as it does to a full one, so six months landing on a Saturday moves to the Monday.
Nil T2 Filing, $300.00 plus HST per tax year
Type your corporation name, pick your unfiled years, pay, and sign Form T183CORP on a secure screen. Your CRA confirmation is emailed within 3 business days.
Start Nil T2 Filing NOW