How to calculate your premium and insurable earnings

To calculate your premium, multiply your gross insurable earnings by your premium rate and divide by 100. If you have more than one NAICS code (NC), you will need to calculate each NC separately.

Premium = insurable earnings x premium rate ÷ 100

For businesses in construction, see more information on calculating your premiums and view our policy on Insurable Earnings in Construction.

Determining insurable earnings

  1. Determine who you are responsible for insuring during the reporting period.
  2. Determine the gross earnings for each person during the reporting period. This includes optional insurance and volunteer forces, if applicable. Gross earnings include items such as room and board, vacation pay, and any taxable benefits that are included in Box 14 of T4 earnings. For details see earnings to include.
  3. Include the labour portion of the contract for contractors or subcontractors, if the WSIB does not consider the contractor to be an independent operator.
  4. Deduct non-insurable gross earnings such as supplementary maternity benefits, executive officers earnings, not included in mandatory coverage in construction, and excess earnings above the annual maximum from your total gross earnings. The result is your total insurable earnings. See examples of non-insurable gross earnings under earnings to exclude below.

No earnings to report?

Write ‘0’ (zero) as the insurable earnings for any NC that has zero earnings for this reporting period. If your business has closed or stopped employing people, please contact us.

Who you are responsible for insuring

  • Anyone you employ in your business, including family. Full-time, part-time, seasonal or temporary employees, certain domestic employees, unregistered individuals engaged in construction work, students, apprentices, learners and training participants
  • Yourself – if you are an independent operator, sole proprietor, partner or executive officer in the construction industry. See Expanded Compulsory Coverage in Construction for exceptions.
  • For details and exceptions on who must be insured, please see our policy on Workers and Independent Operators

Annual maximum

The WSIB sets an annual maximum for insurable earnings based on the average industrial wage (AIW) for Ontario. For 2020, the annual insurable earnings maximum is $95,400.

Once an individual’s earnings reach the annual maximum, you do not need to report the earnings that exceed the maximum.

Earnings to include

  • Any taxable benefits included in box 14 of the T4 such as wages, annual salary or payments for piece work
  • Room and board that are part of earnings
  • Bonuses and commissions
  • Merchandise awards
  • Profit-sharing
  • Overtime pay
  • Sick pay
  • Vacation pay
  • Severance pay if an Employment Insurance (EI) Record of Employment has not been issued

For the complete list of earnings to include, see appendix I of our Determining insurable earnings policy. Non-insurable earnings, such as top ups to EI maternity benefits or sick pay credits used for early retirement, are not part of your insurable payroll and should be excluded.

Earnings to exclude

Some examples of non-insurable earnings include:

  • Maternity benefits paid in addition to EI benefits
  • Sick pay credits used by an individual who is off work on early retirement and is kept on the payroll until the time of retirement
  • Retiring allowance paid over a series of months after  employment has ended
  • Severance pay if an EI Record of Employment is issued to an individual
  • Earnings of Ontario-based an employee’s temporarily out of the province that are reported to other Canadian workers' compensation boards

For a comprehensive list of non-insurable earnings, see appendix II of our policy on Determining insurable earnings.

If you are a business in the construction industry, read about Mandatory Coverage in the Construction Industry for more details about insurable gross earnings.

If your business has more than one NAICS code (NC)

Earnings are considered either direct or common.

Direct earnings can be assigned to a NC directly from records that clearly show the earnings by business activity.

Common earnings are for work completed to support business activities in two or more NC, for example human resources, accounting, administrative staff, people covered by optional insurance, and sole proprietors, partners of a partnership or executive officers of a corporation in the construction industry. If common work is performed, you must include a portion of the common earnings with each NC when calculating premiums as follows:

  1. Determine the direct earnings for each NC.
  2. Total the direct earnings from all NC.
  3. Determine the total common earnings.
  4. Divide direct earnings for each NC by the total direct earnings for all NCs. This results in the proportion of common earnings to use for each NC. Then multiply each amount by 100 to get the percentage.
  5. Multiply the percentage for each NC by the total common earnings. This gives the amount of common earnings to assign to each NC description.
  6. Add the common earnings amount plus direct earnings for each NC.

See the example below:

An employer manages four different business activities; therefore, the employer has four different NC with a total direct earnings amount of $500,000. There are common earnings of $48,000. The common earnings must be pro-rated over the direct insurable earnings in each NC.

Step 1: Employer determines the amount of direct earnings and the percentage of total direct earnings from all people you are responsible for insuring for each NC.

NAICS code NAICS description Direct insurable earnings Percentage of total direct earnings

314110

Carpet and rug mills

$ 100,000

20%

314910

Textile bag and canvas mills

$ 250,000

50%

314120

Curtain and linen mills

$ 60,000

12%

314990

All other textiles product mills

$ 90,000

18%

TOTAL

 

$ 500,000

100%

Step 2: Apply the percentage of total direct earnings to the common earnings to determine the proportion of common earnings to be assigned to each NC.

NAICS code NAICS description Percentage of Common Earnings Pro-rated Common Earnings per NC

314110

Carpet and rug mills

20% of $ 48,000

$ 9,600

314910

Textile bag and canvas mills

50% of $ 48,000

$ 24,000

314120

Curtain and linen mills

12% of $ 48,000

$ 5,760

314990

All other textiles product mills

18% of $ 48,000

$ 8,640

TOTAL

 

100%

$ 48,000

Step 3: Add the direct insurable earnings and the pro-rated common earnings for each NC.

NAICS code NAICS description Direct insurable earnings Pro-rated common earnings Insurable earnings per NC

314110

Carpet and rug mills

$ 100,000

$ 9,600

$ 109,600

314910

Textile bag and canvas mills

$ 250,000

$ 24,000

$ 274,000

314120

Curtain and linen mills

$ 60,000

$ 5,760

$ 65,760

314990

All other textiles product mills

$ 90,000

$ 8,640

$ 98,640

TOTAL

 

$ 500,000

$ 48,000

$ 548,000