You have to file your tax return on time even if some slips and receipts are missing. Under reported income may result in interest and/or penalties charge.
Know what slips you are expecting
Employers are generally required to send your T4 slips by the end of February in the year following the year in which you received payments. Contact your employer if you don’t receive it by the beginning of April.
Slips from government (Old Age Security, Canada Pension Plan, and Employment Insurance) should usually arrive in March.
Be careful with the investment slips. Sometime you have to dig it out from the pile of statements and promotional pamphlets. And they often come late. T3 slips (reporting trust income) are often not available until after March 31. Make sure you have all of them before doing your tax return especially you have different investments in different banks, insurance companies, or investment firms.
Try your best to get the slips
If you are missing any slips, call the issuer for a new copy. For some slips such as T4s or government slips, you can download them online from your account in the Canada Revenue Agency (CRA) (you have to register your on-line account first).
Cannot get it, estimate it
If you have made a reasonable attempt to obtain your slip but had no luck, you need to give the CRA the best estimate. Use any pay stubs or statements you may have to estimate the income to report and any related credits and deductions to claim. Enter the estimated amounts on the appropriate lines of your return. Attach the pay stubs or statements to your paper return and a note stating the payer’s name and address, the type of income involved, and what you are dong to get the slip. If you are filing electronically, keep all your documents in case the CRA asks to see them at a later date.
Don’t be late
You must file your return before due date even if you know information is missing. Give the best estimate and get it in on time. Or you may be charged a late filing penalty and interest. And don’t just leave it out and hope the CRA will not know it. Otherwise, you may be charged so called repeated failure to report income penalty.