WSIB Ontario: Employer Registration, Premiums, and Payroll

WSIB — the Workplace Safety and Insurance Board — is Ontario's workers' compensation authority. Employers in compulsory industries must register within 10 days of hiring their first worker and pay premiums on all insurable earnings. WSIB covers approximately 91% of Ontario's workforce across more than 300,000 registered employers. This guide covers Ontario only; Quebec employers fall under CNESST, not WSIB.

WSIB is one of the mandatory payroll costs that Ontario employers discover either during registration or, in the worst cases, during a WSIB compliance review. For new Ontario employers especially, understanding the registration requirement, the premium calculation, and the WSIB clearance certificate process before the first worker is hired prevents penalties that accrue from the date registration was required — not the date the employer finds out they were required.

This guide covers what WSIB is and why it exists, which Ontario employers must register and which can opt in voluntarily, what counts as insurable earnings, how premium rates are assigned and calculated, the new employer registration process, what to do when a workplace injury occurs, and how WSIB integrates with your payroll administration. For broader Ontario payroll compliance obligations including source deductions and employer health tax, see the guide on Ontario payroll compliance.

What WSIB is and what it does

WSIB administers Ontario's workplace safety and insurance system under the Workplace Safety and Insurance Act, 1997 (WSIA). The system is a collective liability model: employers in Schedule 1 (the majority of Ontario employers) pay premiums into a collective pool, and WSIB pays benefits to injured workers regardless of fault. Injured workers give up their right to sue their employer in exchange for access to no-fault benefits. Employers give up their exposure to civil lawsuits from injured workers in exchange for paying premiums.

The benefits WSIB provides to injured workers include payment of medical and rehabilitation costs, loss of earnings benefits (LOE) equal to 85% of the worker's pre-injury net earnings, non-economic loss (NEL) benefits for permanent impairments, and survivor benefits when a work-related injury or illness causes death. Workers do not contribute to WSIB — the entire premium is an employer cost.

WSIB also runs prevention programs, inspections, and compliance initiatives in partnership with provincial health and safety enforcement. The Ministry of Labour, Immigration, Training and Skills Development conducts workplace safety inspections and issues orders; WSIB finances prevention activities and tracks injury data by industry.

Ontario's system operates on an advance-reserve basis, meaning WSIB maintains a target ratio of assets to liabilities and adjusts premium rates across rate groups annually to maintain financial sustainability. WSIB's 2024 reserve ratio was above 100%, meaning its assets exceeded projected benefit liabilities.

The equivalent to WSIB in other provinces uses different names: WorkSafeBC in British Columbia, WCB Alberta, WorkSafe Saskatchewan, Manitoba WCB, WorkSafeNB in New Brunswick, WCB Nova Scotia, PEI WCB, WorkplaceNL in Newfoundland and Labrador, and WSCC in the territories. Quebec's system, administered by CNESST, has entirely different premium calculation rules and structures.

Which Ontario employers must register with WSIB

The WSIA divides Ontario employers into compulsory and non-compulsory categories. The division follows industry lines based on the North American Industry Classification System (NAICS) codes.

Compulsory industries (Schedule 1) include construction (all residential and commercial work), manufacturing of all kinds, mining and resource extraction, transportation and warehousing, retail trade, wholesale trade, accommodation and food services (restaurants, hotels, cafes), healthcare and social assistance, most agricultural operations, forestry, utilities, and waste management. If your business falls in any of these sectors, registration is mandatory.

Non-compulsory industries include banks and other financial institutions, insurance carriers and agents, real estate agents and brokers, professional services firms (law offices, accounting practices, management consulting), some arts and entertainment organizations, and private households employing domestic workers. Employers in non-compulsory industries are not required to register but can apply for optional personal coverage or optional employer coverage.

A common source of confusion is the compulsory status of professional service firms that do work on client sites. An accounting firm that sends an accountant to client offices for audit work is in a non-compulsory industry. A construction firm that employs an administrative bookkeeper is in a compulsory industry — both the field workers and the office workers are covered by the same employer account.

Timing of registration: You must apply to WSIB within 10 days of hiring your first worker in a compulsory industry. The registration can be completed online through WSIB's employer portal at wsib.ca. WSIB will review the application, assign a rate group, and issue a WSIB account number. Penalties for late registration apply from the date registration was required, not the date you applied.

Independent business operators: A sole proprietor or partner who works in the business and has no employees may not be required to register, but also will not be covered for work-related injuries. WSIB offers optional personal coverage for business owners who want coverage for themselves. If you later hire workers, the mandatory registration requirement activates.

What counts as insurable earnings for WSIB

Insurable earnings are the total remuneration you pay to workers up to the annual maximum insurable earnings amount set by WSIB each year. The maximum insurable earnings ceiling changes annually; for 2024 it was set at $110,800 per worker. Any earnings above that ceiling for a single worker are not included in the insurable earnings calculation — you stop counting insurable earnings for that worker once their annual earnings with you exceed the ceiling.

What is included in insurable earnings: Regular wages, salaries, and hourly pay constitute the core of insurable earnings. Also included are vacation pay paid to workers (whether paid on each cheque or as a lump sum), overtime pay, commissions paid as part of the regular wage relationship, bonuses that are part of the employment relationship, and the value of room and board provided to workers where this is part of their compensation.

What is excluded from insurable earnings: Termination pay and severance pay are not insurable earnings — they are paid after the employment relationship ends. Director fees paid to arm's-length corporate directors who are not otherwise employed by the corporation are generally excluded. Tips and gratuities paid directly by customers to workers (not distributed by the employer through payroll) are excluded. The fair market value of non-monetary benefits like employer-provided vehicles or equipment is generally excluded unless specifically included by WSIB policy for a specific industry.

Independent contractors and deemed worker status: You do not pay WSIB premiums on amounts paid to genuinely independent contractors who carry their own WSIB coverage. The risk arises when an independent contractor working in a compulsory industry does not have their own WSIB coverage. WSIB can deem such a contractor to be your worker and assess premiums on amounts paid to them. For construction projects, this creates significant exposure — a general contractor who hires subcontractors without verifying their WSIB standing can be held liable for premiums on all subcontractor earnings. The WSIB Clearance Certificate system (described below) exists specifically to address this.

How WSIB premium rates are calculated

WSIB assigns each employer to a rate group based on the NAICS code that matches the employer's principal business activity. Rate groups cluster similar businesses together in a collective insurance pool. A construction framing contractor is in a different rate group than a drywall contractor, which is in a different rate group than an electrical contractor, even though all three operate on construction sites.

Each rate group has a base premium rate expressed in dollars per $100 of insurable earnings. Rates vary significantly by industry because workplace injury frequency and severity vary significantly by industry. A sedentary office environment in a non-compulsory professional services firm, if it were enrolled, might face a rate of under $1 per $100 of insurable earnings. A high-risk mining or underground construction operation faces rates that can exceed $10 per $100 of insurable earnings.

Premium calculation formula: Premium = (Insurable Earnings ÷ 100) × Premium Rate

An employer with $400,000 in insurable earnings and a rate of $3.25 per $100 would pay: ($400,000 ÷ 100) × $3.25 = $13,000 in annual WSIB premiums.

New Experience Rating (NER): WSIB introduced the New Experience Rating program in 2020, replacing the prior NEER and MAP programs. NER adjusts individual employer premium rates based on how their actual claims costs compare to what is expected for their rate group, given their insurable earnings. An employer with fewer and less costly claims than the rate group average receives a NER rebate applied to future premiums. An employer with more or costlier claims than the rate group average faces a NER surcharge.

NER applies to employers who have been registered with WSIB for at least three years and whose insurable earnings are large enough for their experience to be statistically credible. Smaller employers are partially credibility-rated and partially rated at the rate group average. Very small employers are rated entirely at the rate group average.

Annual adjustment: WSIB recalculates rate group rates each year based on the collective claims experience of the rate group and the overall reserve position of WSIB. An individual employer's rate can change each year both because of the rate group adjustment and because of the employer's own NER adjustment.

Registering with WSIB as a new Ontario employer

Registration is straightforward and completed online. You will need your business number (the CRA 9-digit BN), your business legal name and operating name, your NAICS code or a description of your business activities, your expected annual payroll for the coming year, and the date you first hired a worker (which may be retroactive if you hired before registering).

WSIB will review your application and assign a rate group and initial premium rate based on your NAICS code. You will receive a WSIB account number. New employers typically pay premiums quarterly in their first year; the remittance schedule may change based on annual premium amounts as your account matures.

Clearance Certificates: A WSIB Clearance Certificate confirms that a business's WSIB account is in good standing. Before paying a contractor for work in a compulsory industry, you should request a current Clearance Certificate. WSIB makes Clearance Certificates available through its online system and they can be generated by the contractor. A certificate confirms the contractor is registered, their account is current, and WSIB will not hold you liable for their workers' WSIB premiums.

If a contractor cannot produce a Clearance Certificate, you have two options: withhold payment until they provide one, or assume WSIB liability for premiums on the amounts paid to them. For construction, this is not a theoretical risk — WSIB actively enforces subcontractor premium liability on general contractors.

Payroll reporting: WSIB requires annual reconciliation reporting. Each year, you report your actual total insurable earnings for the prior year and reconcile against any installments you paid during the year. If the reported insurable earnings are higher than the estimated amount you reported when you set up installments, you will owe additional premiums. If lower, WSIB will credit or refund the difference.

Record keeping: Ontario employers are required to maintain payroll records sufficient to support their WSIB annual reconciliation. This means records showing total remuneration paid to each worker per payroll period and the basis on which each worker was classified as a worker (rather than an independent contractor excluded from insurable earnings). WSIB can audit employer premium accounts, and an audit that reveals underreported insurable earnings results in assessment for the additional premiums plus interest and potential penalties. Maintaining accurate payroll records for a minimum of six years is the safest practice, consistent with CRA's general record-keeping requirement for business records.

Reporting a workplace injury to WSIB

When a worker is injured on the job or reports a work-related illness, the employer has three obligations that run simultaneously: provide first aid and ensure the worker gets medical attention, complete and file a Form 7 (Employer's Report of Injury or Disease) with WSIB within three business days of learning about the injury, and cooperate with WSIB's claim investigation and the worker's return-to-work process.

The Form 7 collects information about the injury, the worker's employment, their earnings, and the employer's contact information. Filing the Form 7 on time is mandatory. Late filing without a satisfactory explanation can result in a penalty.

Return to work (RTW) obligations: The WSIA places significant obligations on employers regarding return to work. An employer with 20 or more workers must offer the injured worker a suitable modified or alternative position if one is available during the recovery period. The employer must cooperate with WSIB's return-to-work coordinator and must not penalize a worker for filing a WSIB claim. Failure to meet RTW obligations can result in WSIB levying costs directly against the employer.

The impact on NER: Every claim affects the employer's NER score. A claims cost that WSIB pays on a worker's behalf enters the employer's NER calculation. Large claims — long-term loss of earnings payments, expensive medical rehabilitation — can persist in the NER calculation for years and push the employer's premium rate upward. This is the primary reason why safety programs, rapid return-to-work processes, and genuine injury prevention reduce payroll costs: fewer claims means lower premiums under NER.

WSIB and payroll: what changes at remittance time

WSIB premiums are not source deductions in the same sense as CPP contributions, EI premiums, or income tax. They are employer-paid obligations that do not involve withholding from employee paycheques. The worker sees nothing on their pay stub related to WSIB — the premium is entirely the employer's cost.

WSIB premiums do not flow through the same CRA remittance system as payroll source deductions. They are paid directly to WSIB on WSIB's own remittance schedule. For source deductions — the income tax, CPP, and EI that must be withheld from worker pay — see the guide on payroll deductions in Canada, which covers the CRA remittance framework separately from WSIB.

Accounting treatment: WSIB premiums are a payroll-related operating expense. In most accounting systems, WSIB premiums are coded to a payroll-related expense account alongside EI employer premiums and CPP employer contributions. For accrual-basis accounting, employers accrue WSIB expense each payroll period based on insurable earnings and their current premium rate, then reconcile the accrual when the WSIB annual report is filed.

Payroll software and WSIB: Many Canadian payroll software platforms — and specialized payroll service providers — include WSIB premium tracking as part of their payroll reporting. The system calculates the insurable earnings for each worker per payroll period and accumulates the WSIB premium liability across the year. This makes the annual reconciliation significantly simpler because the insurable earnings figure is already computed. For businesses with ten or more Ontario employees, using a payroll service that handles WSIB tracking alongside source deduction remittances reduces the risk of year-end reconciliation errors.

For an independent contractor classification question that affects both WSIB premium liability and CRA source deduction obligations, the guide on employee vs contractor Canada covers how CRA applies the four-factor test, which largely mirrors how WSIB analyzes the same working relationships.

For Ontario businesses that want a fully managed employment compliance model — one that includes WSIB compliance alongside CPP, EI, and source deduction management — PEO Canada covers how professional employer organizations handle employer obligations for businesses operating in Ontario and other provinces outside Quebec.

Quick Answers

What is WSIB? WSIB is the Workplace Safety and Insurance Board, Ontario's workers' compensation authority. It pays medical and income replacement benefits to workers injured on the job, funded by employer premiums calculated on insurable earnings.

Do I have to register with WSIB? If your business operates in a compulsory industry in Ontario — including construction, manufacturing, retail, transportation, food services, and healthcare — you must register within 10 days of hiring your first worker. Non-compulsory industries such as legal and financial services can opt in voluntarily.

How much are WSIB premiums? WSIB premiums vary by industry. The rate is expressed as a dollar amount per $100 of insurable earnings and ranges from under $1.00 in low-risk industries to over $10.00 in high-risk industries. Your individual rate is further adjusted annually based on your claims history relative to your rate group through the New Experience Rating program.

Do I pay WSIB premiums on independent contractor payments? Not if the contractor has their own WSIB coverage. Always request a WSIB Clearance Certificate before paying a contractor for compulsory industry work. If the contractor has no WSIB coverage, you may be liable for premiums on amounts paid to them.

Does WSIB apply in other provinces? No. WSIB is Ontario-specific. Each province has its own workers' compensation system. British Columbia uses WorkSafeBC, Alberta uses WCB Alberta, and Quebec uses CNESST. Employers with workers in multiple provinces must register separately in each province where they employ workers.

Ready to get Ontario payroll — including WSIB, EHT, and source deductions — running on a clean and compliant foundation? Request a free payroll assessment and a specialist will review your Ontario employer obligations and recommend the right path forward.