WSIB Unregistered Employer Back Premium Calculator
Registration is due within ten days of hiring your first worker, and nothing reminds you. Work out the back premiums for every year you were uncovered, the interest and penalties on top, and what an injury claim costs when there is no coverage behind it.
total exposure
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Back Premiums Year by Year
| Year | Insurable Earnings | Premium | Years Accruing | Interest |
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What Makes Up the Total
| Item | Basis | Amount |
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Obligations You Missed
| Requirement | Rule | Position |
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Points That Decide This
What to Do Next
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Disclaimer: Under the Workplace Safety and Insurance Act an employer in an industry covered by Schedule 1 must register with the Workplace Safety and Insurance Board within ten days of becoming an employer, and must report and pay premiums on insurable earnings. Mandatory coverage in the construction industry has applied to most independent operators, sole proprietors, partners and executive officers since 1 January 2013, subject to limited exemptions. Where an employer has not registered, the Board may assess premiums for prior periods together with interest and administrative penalties, and where a worker is injured while the employer is unregistered the Board may hold that employer responsible for the cost of the claim in addition to the premiums owed. The claim cost exposure shown here is the amount you enter and is illustrative only; actual claim costs depend entirely on the injury and can be far larger than a premium assessment, particularly where an injury results in long-term benefits. Interest and penalty figures in this calculator are estimates using the rate you enter and a modelled administrative penalty, and the Board applies its own rates, methods and discretion. The maximum insurable earnings figure of $121,700 per worker used here has been supplied to us and postdates our verification; please confirm it, the earnings ceiling for each earlier year and your rate group against the current WSIB premium rate schedule. This page is general information, not legal or accounting advice.
Ten Days, and Nothing Tells You
The obligation starts when you hire your first worker, and registration is due within ten days. No letter arrives, no government system flags it, and incorporation does not trigger it. A business can operate for years in good faith without anyone raising the question.
What usually surfaces it is a client asking for a clearance certificate, an audit, or an injury. The first two are inconvenient. The third is the one that hurts.
The premiums are the small part. A few years of back premiums with interest is a bill a business can usually absorb. If a worker was injured during the uncovered period, the Board can look to the employer for the cost of that claim, and a serious injury runs to numbers no small corporation carries.
Who Has to Register
Coverage is compulsory across most of the industries that carry physical risk, and the reach in construction is wider than in any other sector.
| Situation | Registration Required |
|---|---|
| Construction corporation with employees | Yes |
| Construction, owner working alone | Yes, mandatory coverage since 2013 |
| Trucking, cleaning, landscaping with workers | Yes, in covered industries |
| Executive officer doing no construction work | Narrow exemption may apply |
| Corporation with no workers at all | Generally no |
| Home renovator working for an occupant | Depends on the arrangement |
The exemptions are the part people lean on and the part that most often fails. An executive officer exemption depends on performing no construction work at all, which is not the same as spending most of your time in the office.
Premiums Run From When You Should Have Registered
An assessment does not start from the date the Board finds you. It reaches back across the period you were operating uncovered, and each year is calculated on that year’s insurable earnings at that year’s rate, with the earnings ceiling for that year applied per worker.
Interest then accrues from each year separately, so the oldest year carries the most. A business four years behind is not paying four times one year’s premium; it is paying four premiums plus compounding on the earliest ones.
The ceiling applies per worker, not to total payroll. A crew of four on good wages can be well under the aggregate ceiling while two of them individually exceed it. Applying the cap to the payroll total understates the assessment, and the Board will not make that error.
Subcontractors Are Assessed Too
An unregistered employer usually has a second problem sitting alongside the first. Payments made to subcontractors who had no clearance certificate of their own can attract premiums as well, on the same principal liability rule that applies to registered contractors.
So the assessment can cover both your own workers and the labour portion of what you paid out, which is why the number on an unregistered file is often larger than the owner’s own payroll would suggest.
The Injury Scenario
This is the reason the ten-day rule exists. When a worker is injured, the Board pays the claim regardless of whether the employer was registered. Where the employer was not registered, the Board can then look to that employer for the cost.
A minor injury with a few weeks off work is manageable. A back injury producing years of partial benefits, or anything permanent, produces a figure that has no relationship to the premiums that were avoided. That asymmetry is the whole argument for registering the week you hire someone.
Personal liability sits behind the corporation on some of this. Directors can face consequences where obligations went unmet, and a corporation without assets does not end the matter. Anyone treating non-registration as a corporate risk only should take advice on that specifically.
The Clearance Certificate Problem
An unregistered business cannot obtain a clearance certificate, and an account in arrears usually cannot either. That closes off work with general contractors, public sector clients and anyone whose accounts payable process requires one.
It also tends to be how the issue finally surfaces. A contractor asks for a certificate before releasing a draw, the request fails, and a compliance problem that had been theoretical for three years becomes a cash flow problem this week.
Voluntary Registration Is Better Than Being Found
Coming forward is not a clean slate and the back premiums do not disappear. What it can change is the treatment of penalties, which are discretionary, and it puts the business in a very different position than an employer who was audited or discovered after an injury.
The practical order is to quantify the exposure first, understand what each year costs, and then approach the Board with the figures already worked out rather than waiting to be told.
What This Calculator Does Not Cover
- Whether your business is in a covered industry, which depends on the classification of what you actually do
- Whether a specific exemption applies to an executive officer or an independent operator
- The earnings ceiling and rate for each earlier year, which differ from the current ones
- Actual claim costs, which depend entirely on the injury and its long-term consequences
- Director and officer liability for unmet obligations
- Objections and appeals where an assessment has already issued
Where you are already paying subcontractors, the clearance certificate exposure sits on top of this and is calculated separately. Our WSIB reporting and compliance service covers registration, the back-year reconciliations, the premium calculation and dealing with the Board.
Frequently Asked Questions
Common questions on registering late with the WSIB.
Related Calculators and Guides
More tools for employers with WSIB obligations.
Quantify It Before You Approach the Board
Send us the date you hired your first worker, the payroll for each year since, and what you have paid to subcontractors. We will work out the back premiums year by year, register the business, prepare the outstanding reconciliations and handle the Board on the penalty position.