Methodology and sources
How the calculation is done, with which parameters, and when they were last verified. This page exists so that you can challenge the result — that is the only reason to trust it.
The formula
The personalized rate is the sum of a risk-related portion and a fixed portion that is the same for every employer:
personalized rate = (short-term risk index × short-term unit rate + long-term risk index × long-term unit rate) × retrospective factor + uniform fixed rate
Each horizon — short term and long term — is computed separately, with its own reference period, its own credibility parameter and its own costs.
1. Expected costs
The sum, over the three years of the reference period, of the year's insurable wages multiplied by the unit's experience ratio for that year, divided by 100. In the short term the ratio changes every year — 2022, 2023 and 2024 for 2026 ratemaking. In the long term the CNESST publishes a single ratio for the whole 2021–2023 period, which it applies to each of the three years.
These ratios are published by classification unit in Schedule 1 of the Regulation respecting financing. They sit in this site's reference data, which makes it possible to reconstruct the expected costs from the unit and the insurable wages alone, without having your Notice of Calculation at hand. The reconstruction remains an estimate: the CNESST uses the wages actually declared for each year and takes into account, where applicable, participation in a prevention mutual. When the amount from the notice is entered, that is the one used.
2. Experience index
Retained costs multiplied by the adjustment factor for recalculations, divided by expected costs. An index above 1 means your injuries cost more than your classification unit anticipated.
3. Degree of personalization
Expected costs divided by the sum of expected costs and the credibility parameter — $4,980 in the short term, $232,400 in the long term for 2026. The higher your expected costs, the more your own record weighs in your rate. This is the mechanism that shields small employers from a violent swing on a single accident, and that makes large employers very sensitive to their performance.
4. Ceiling on the index
The experience index is capped at the lesser of 3 and 1 + 6 × degree of personalization. An employer with little personalization therefore sees a bad result trimmed; a heavily personalized employer pays it in full, up to three times the expected level.
5. Risk index
One plus the degree of personalization multiplied by the gap between the capped index and 1. This is the formula that expresses “how far your own record replaces the average of your unit”.
6. Putting it together
The short-term and long-term risk indices multiply their respective unit rates. The total is adjusted by the retrospective factor where the employer is subject to it, then the uniform fixed rate is added — $0.2294 for a provincial employer in 2026, $0.2728 under retrospective ratemaking.
The simulation
The calculation is run a second time with the retained costs reduced by the percentage requested, all else being equal. The gap between the two premiums gives the annual saving; it is multiplied by three, the length of time an injury stays in the reference period. This is a deliberately conservative approximation: it ignores the compounding effect of sustained improvement over several consecutive years.
Verifying the calculation
In the employer's guide, the CNESST publishes a full worked example arriving at a rate of $1.93. That example is replayed automatically before each publication of this site, and the twelve intermediate values — expected costs, experience indices, degrees of personalization, risk indices, short-term and long-term rates, total based on risk, final rate — must all be reproduced before deployment is allowed. This is what guarantees that an annual revision of the parameters does not silently break the formula.
The same example is replayed a second time supplying only the classification unit and the four insurable wage figures, without any of the numbers from the Notice of Calculation. The expected costs reconstructed from the ratios must then recover the $17,763 and $78,225 detailed in section 2 of the guide, and the final rate the same $1.93. This second check is what makes the “choose your unit” path trustworthy rather than merely convenient.
A further cross-check, run when the parameters are imported: for each of the 170 units, the short-term rate plus the long-term rate plus the uniform fixed rate must reproduce, to the cent, the general rate published in the Schedule of Rates. All 170 agree — so two separate CNESST publications confirm each other.
A note on the English unit titles: they are condensed from the official titles in the 2026 Schedule of Rates, and each one is matched to its unit number by that same cross-check on the general rate. The full legal wording is the one in the Regulation respecting financing.
Worth noting: the example in the guide uses its own illustrative parameters, distinct from the real 2026 values. It therefore validates the formula, not the parameters. The parameters themselves come from the official publications listed below.
Known limits
- The adjustment factor for retrospective ratemaking is not exercised by the official example: that part of the calculation follows the guide but is not validated against a published case.
- The annual premium is estimated from the insurable wages entered, without accounting for periodic payments or year-end adjustments.
- Cost sharing, imputation transfers and pending contestations are not modelled: they change the retained costs upstream of the calculation.
- An employer classified in several classification units has a composite rate: their expected costs add up across all their units. The simulator handles one at a time.
- Insurable wages left blank are replaced by the current year's figure. For a business growing or shrinking fast the gap is real — the simulator flags it rather than hiding it.
Parameters used
Parameter version: 2026. Last verified: July 26, 2026. Next revision planned: January 15, 2027.
| Parameter | 2026 value |
|---|---|
| parametres › seuilAssujettissement | 1,660 |
| parametres › seuilAssujettissementPrimeApprox | 10,000 |
| parametres › credibiliteCT | 4,980 |
| parametres › credibiliteLT | 232,400 |
| parametres › plafondIndiceBase | 3 |
| parametres › plafondIndiceCoefficient | 6 |
| parametres › facteurRetro › provincial | 1.037 |
| parametres › facteurRetro › federal | 1.029 |
| parametres › tauxFixeUniforme › provincial | 22.94% |
| parametres › tauxFixeUniforme › provincialRetro | 27.28% |
| parametres › tauxFixeUniforme › federal | 9.55% |
| parametres › tauxFixeUniforme › federalRetro | 10.14% |
| parametres › seuilLesionCT | 5% |
| maximumAnnuelAssurable › 2021 | 83,500 |
| maximumAnnuelAssurable › 2022 | 88,000 |
| maximumAnnuelAssurable › 2023 | 91,000 |
| maximumAnnuelAssurable › 2024 | 94,000 |
Official sources
-
Calculation of Personalized Rate 2026 — Employer's Guide, CNESST
Accessed on July 26, 2026
-
2026 Schedule of Rates — Classification Units, CNESST
Accessed on July 26, 2026
-
Unit Rates Based on Risk and Experience Ratios for Classification Units — Personalized Ratemaking 2026, CNESST
Accessed on July 26, 2026
-
Threshold for personalized ratemaking, CNESST (published in French only)
Accessed on July 26, 2026
-
Personalized ratemaking parameters, CNESST (published in French only)
Accessed on July 26, 2026
Known limits
No calculator replaces the analysis of a real case. This tool produces an estimate based on average assumptions; particular situations — sector-based schemes, collective agreements, exceptional statuses — can change the result significantly. The limits specific to your own calculation are shown directly under the result, as you type.
Report an error
If a rate looks wrong or out of date, write to contact@tauxcnesst.ca and name the official source. Corrections are applied and dated on this page.