Ontario Payroll Tax Guide for Small Businesses

A new Ontario employee can cost materially more than the salary in the offer letter. Beyond wages, employers may need to withhold income tax, Canada Pension Plan contributions, and Employment Insurance premiums, then fund their own CPP and EI obligations and assess exposure to Ontario Employer Health Tax. Missing one setup step can create CRA interest, penalties, employee payroll corrections, and avoidable year-end work.

This Ontario payroll tax guide outlines the core payroll obligations for Ontario employers. It is written for small businesses, incorporated professionals, contractors with employees, and growing companies that need a practical compliance framework.

What Ontario employers must manage

Ontario payroll is primarily administered through the Canada Revenue Agency, but provincial rules affect the income tax calculation and may create a separate Employer Health Tax liability. Employers must also consider Workplace Safety and Insurance Board coverage where applicable. These are related obligations, but they are not all calculated or reported the same way.

For each employee, payroll begins with accurate onboarding information. Obtain a completed federal TD1 and Ontario TD1, confirm the employee’s social insurance number, establish pay frequency, and determine whether the worker is an employee or an independent contractor. A contractor classification is not created simply by calling someone a contractor or paying them without deductions. The actual working relationship matters.

Once the employment relationship is correctly established, the employer generally withholds federal and Ontario income tax, CPP contributions, and EI premiums from each pay. The employer then contributes its required share and remits the combined amount to the CRA.

Income tax withholding

An employee living and working in Ontario pays federal and Ontario personal income tax. Employers do not normally calculate final tax manually. Payroll software or the CRA payroll deductions tables apply the withholding based on pay, pay frequency, TD1 claim amounts, taxable benefits, and other relevant information.

The Ontario Health Premium is part of Ontario personal income tax. It is not a separate amount that an employer calculates and remits as a standalone payroll deduction. Proper income tax withholding calculations account for Ontario provincial tax requirements.

Employees may request extra tax withholding, which can be useful when they have investment income, a second job, or deductions that are not reflected in normal payroll. Do not reduce statutory deductions based on an informal employee request. Changes should be supported by the proper CRA authorization or payroll documentation.

CPP and EI contributions

CPP and EI are two of the most visible payroll costs for Ontario employers. CPP is generally withheld from pensionable earnings up to the annual maximum, subject to age, eligibility, and exemption rules. Employers typically match the employee’s CPP contribution. Additional CPP rules can apply at higher earnings levels under the enhanced CPP structure.

EI is withheld from insurable earnings up to the annual maximum. The employer contribution is generally 1.4 times the employee EI premium. The applicable rates and annual maximums change, so payroll settings should be reviewed at the start of each calendar year rather than carried forward without verification.

Certain payments require special attention. Bonuses, commissions, vacation pay, taxable benefits, retiring allowances, automobile benefits, and shareholder compensation can each have different income tax, CPP, or EI treatment. A payment being reported on a paycheck does not automatically mean every deduction applies in the same way.

Ontario Employer Health Tax explained

Employer Health Tax, commonly called EHT, is an Ontario payroll tax paid by employers, not withheld from employees. It is based on Ontario remuneration, which generally includes employment income and taxable benefits paid to employees who report for work at an Ontario permanent establishment or are attached to one.

Eligible Ontario employers may claim an annual EHT exemption of up to $1 million in Ontario payroll. Associated employers must share one exemption, rather than each claiming a separate $1 million amount. This is especially relevant for related corporations, businesses with common control, and groups that have expanded through separate legal entities.

For employers above the exemption threshold, EHT is generally calculated at graduated rates, reaching 1.95% of taxable Ontario payroll above the exemption. The exact calculation can depend on total Ontario remuneration, association status, and whether the employer is eligible for the exemption. A business near the threshold should not wait until year-end to estimate its exposure. Monthly payroll growth, new hires, bonuses, and taxable benefits can move the company into a filing and payment obligation.

When EHT registration may be required

Registration requirements depend on the employer’s Ontario payroll and expected EHT liability. An employer that exceeds the relevant thresholds may need to register, file annual returns, and make installment payments. Even if no EHT is ultimately payable because payroll remains within the exemption, tracking Ontario remuneration is still good practice.

Businesses with employees in several provinces need to allocate payroll carefully. The fact that a company is incorporated in Ontario does not by itself decide EHT treatment. Employee work location, reporting structure, and permanent establishment connections can all matter. Remote workers have made this analysis more common, particularly for Toronto, Ottawa, and other Ontario businesses hiring across Canada.

CRA remittances: timing matters as much as accuracy

After withholding payroll deductions, an employer holds money on behalf of the government. Those funds are not operating cash. CRA remittance deadlines depend on the employer’s assigned remitter type, which is generally based on average monthly withholding amounts and compliance history.

New employers are commonly regular remitters and usually remit by the 15th day of the following month. Larger withholding amounts can place an employer in an accelerated remitter category with more frequent deadlines. The CRA may also assign a different schedule based on its rules, so businesses should confirm their remitter type in their CRA account or registration correspondence.

Late payroll remittances can attract penalties even when the payroll return is eventually correct. The practical control is simple: reconcile each payroll run, move the remittance amount to a separate account if needed, and schedule payment before the deadline. Do not wait for month-end bookkeeping to determine how much is owed.

Payroll records and year-end reporting

Ontario employers should maintain a complete payroll file for every worker. This includes TD1 forms, employment agreements, pay records, timesheets where relevant, benefit records, vacation calculations, reimbursements, taxable benefit support, and proof of CRA remittances. Records generally need to be retained for at least six years from the end of the last tax year they relate to.

At year-end, employers must prepare T4 slips and a T4 Summary for employees. T4s report employment income, income tax deducted, CPP, EI, and many taxable benefits. The filing deadline is generally the last day of February following the calendar year. Employees also need their slips by that deadline.

Accuracy at year-end depends on accurate payroll throughout the year. Correcting a missed vehicle benefit or bonus in February is possible, but it often means amended slips, employee confusion, and extra professional fees. Review taxable benefits before the final payroll whenever possible.

Common payroll mistakes Ontario businesses should avoid

The most expensive payroll errors are often routine administrative gaps rather than complicated tax planning issues. Common examples include:

• Paying a worker as a contractor when the facts indicate employment.
• Forgetting to add taxable benefits to payroll income.
• Using outdated CPP, EI, or tax table settings after January 1.
• Missing CRA remittance deadlines because payroll funds were used for operations.
• Treating related companies as independently entitled to separate EHT exemptions.
• Failing to review EHT exposure after rapid hiring or an acquisition.

A payroll review is particularly valuable for owner-managed corporations. Salary, dividends, management fees, vehicle use, health benefits, and family employment can affect both tax results and payroll reporting. There is no universal best mix of salary and dividends. The appropriate approach depends on cash flow, CPP objectives, corporate income, personal income, financing needs, and available deductions.

A practical Ontario payroll compliance process

A dependable process starts with a payroll calendar. Map each pay date, CRA remittance date, EHT installment date if applicable, and T4 deadline. Then reconcile gross pay, deductions, employer costs, and remittances every pay period or month, depending on payroll volume.

Use payroll software that is updated for current CRA rates, but do not treat software as a substitute for judgment. The system needs correct inputs for worker status, taxable benefits, location, vacation pay, and special payments. Professional review is useful when your business has cross-provincial employees, shareholder payroll, complex benefits, or payroll that is approaching the Ontario EHT threshold.

BOMCAS Canada supports Ontario businesses with payroll administration, bookkeeping, CRA remittances, T4 preparation, EHT review, and payroll cleanup work. The objective is not merely to issue paychecks. It is to keep payroll records defensible, cash requirements visible, and compliance work under control as the business grows.

A well-run payroll function gives owners a reliable view of labor cost before it becomes a filing problem. Set up the right records early, review the numbers regularly, and address classification or EHT questions before the next hiring decision makes them more expensive.