Tax Filing Deadlines: What Missing Them Actually Costs

Tax deadlines are fixed. The penalties for missing them are not optional.

Key Deadlines

United States

April 15: Individual tax returns (Form 1040)
Automatic extension available to October 15, but you must still pay estimated tax by April 15

United Kingdom

October 31: Paper self-assessment returns
January 31: Online self-assessment returns
January 31: Payment of tax owed

Canada

April 30: Individual tax returns
June 15: Self-employed individuals (but tax owed still due April 30)

Australia

October 31: Individual tax returns (unless using a tax agent)
Tax agents can lodge later, but you must be registered with them before October 31

Penalties for Late Filing

US:

5% of unpaid tax per month, up to 25%
Minimum penalty of $485 (or 100% of tax owed) if more than 60 days late

UK:

£100 immediate penalty
£10/day after 3 months (up to £900)
Additional 5% of tax owed after 6 months
Further 5% after 12 months

Canada:

5% of balance owing plus 1% per month (up to 12 months)
Doubles for repeat offenders

Australia:

$313 for each 28-day period late (up to 5 periods)
Additional penalties for false or misleading statements

Penalties for Late Payment

Filing on time but paying late is less severe than not filing at all. But interest accrues from the due date regardless.

US: 0.5% per month plus interest (currently around 8% annually)

UK: 5% of tax unpaid at 30 days, 6 months, and 12 months

The Extension Trap

Extensions give you more time to file, not more time to pay. If you owe tax and don't pay by the original deadline, you'll owe interest and possibly penalties even if you file within the extension period.

When to Start

If your taxes are simple, start 2-3 weeks before the deadline. If they're complex (self-employment, investments, foreign income), start 6-8 weeks ahead.

Add tax filing to your tasks. Confirm it when done, and we'll remind you when it's time to think about it again.