WSIB Premiums

Definition

WSIB premiums are the amounts registered Ontario employers pay to fund the workplace injury insurance system under the Workplace Safety and Insurance Act, 1997. Premiums are calculated as a percentage of insurable earnings paid to workers. Each employer is assigned a classification under the WSIB Rate Framework, which groups businesses into 34 classes based on predominant business activity, using the North American Industry Classification System (NAICS). Each class has its own base rate. Individual employers may receive a risk-adjusted rate based on claims experience relative to their peers within the class.

Key rules

• For 2025, the WSIB average premium rate was approximately $1.30 per $100 of insurable earnings (1.30%). The 2026 average rate is announced in WSIB's annual rate framework publication (confirm current figure).
• Maximum insurable earnings were $117,000 per worker for 2025. This cap is adjusted annually based on average industrial wage growth. Earnings above the cap are not insurable and attract no premium.
• Rates range widely by industry. Low-risk service industries (professional, scientific, technical) may pay below $0.25 per $100; high-risk industries (roofing, structural steel, mining) can exceed $10 per $100.
• The Rate Framework (in effect since 2020) uses a six-year experience window: an individual employer's rate can differ from the class base rate by risk-adjustment factors derived from claims experience.
• Reconciliation: employers that pay by monthly or quarterly statement reconcile actual insurable earnings at year-end and true up the premium; under- or over-remittances are settled in the reconciliation period.

Example

A Toronto software development corporation is classified in WSIB Class G (Professional, Scientific and Technical) with an assigned rate of $0.25 per $100 for 2026 (illustrative). It pays three developers $120,000, $95,000, and $80,000 in 2026. Insurable earnings per worker are capped at $117,000 (assume 2026 figure, confirm), so Developer 1's insurable earnings are $117,000; Developer 2's are $95,000; Developer 3's are $80,000. Total insurable earnings = $292,000. Annual premium = $292,000 × 0.25% = $730.

Common mistakes

• Including earnings above the insurable maximum. Only the first $117,000 per worker (2025 cap) is subject to WSIB premiums. Continuing to remit on higher salaries overstates the liability.
• Using the wrong classification code. WSIB assigns a classification based on the predominant business activity; an incorrect NAICS code can result in significantly higher (or lower) premiums and may trigger reclassification penalties.
• Ignoring experience rating. Claims history directly affects the assigned premium rate. Investing in workplace safety and return-to-work programs can reduce the rate over time.
• Failing to reconcile. Annual reconciliation compares estimated insurable earnings remitted during the year to actual amounts. Failure to file the reconciliation triggers penalties and interest.

Related concepts