Box 24 is an information box. It does not go anywhere on your tax return. The T4 slip shows a line number on where to report a box on your income tax return. If there is no line number provided, then it does not get reported on your tax return.

If you look at your T4 slip, you should notice that most of the boxes have a line reference except boxes 24 and 26. CRA's publication Employers' Guide Filing the T4 slip and Summary says they use T4 boxes 24 and 26 information for "pensionable and insurable earnings review (PIER) reports to check your T4 slips for CPP and EI deficiencies."

As a general rule, if you are overriding any calculations in your tax program ... you are doing it wrong.

Tax software has generally paid computer programmers to code in all the tax rules. When an override is necessary ... the deduction is usually optional or an advanced tax calculation.

Box 24 represents the amount of insurable earnings subject to the maximum limit used to calculate the employee's EI premiums. This means it is box 14 less any earnings that are not subject to EI premiums. (See above for exclusion examples.)

There is no age limit to deducting EI premiums. However, the following employment is not insurable:

• casual employment - see the definition here
• non-arm's length employment - i.e. related people

Box 26 represents the pensionable earnings subject to the maximum limit. This means it is box 14 less any earnings that are not subject to CPP contributions.

So what are some of the exceptions? Some examples for CPP contributions when the income is not pensionable are:

• an employee is under 18 or over 70 years of age;
• an employee is between 65 and 70 years of age and elected to stop CPP contributions by submitting Form CPT 30 with parts A, B and C completed; prior to 2012, the exception was the employee received a CPP retirement pension
• an employee is between 65 and 70 years of age and elected to restart CPP contributions by submitting Form CPT 30 with parts A, B and D completed; prior to 2012, the exception was the employee received a CPP retirement pension
• the employee received CPP disability pension;
• any income or benefits listed in CRA's publication RC4120 chapter 2 of Employer's Guide - Payroll Deductions and Remittances.

For most people, T4 slip boxes 24 and 26 will match box 14. Prior to 2012, if the amounts did match box 14, they were generally left blank. That is no longer an acceptable practice due to the changes in CPP that came into effect in 2012.

You may be able to get a slip for a current or previous year if the issuer sent them to the CRA. If you use “CRA Account” with the CRA, you may be able to view your tax slips online. You can also request a copy from the CRA or by calling 1-800-959-8281.