Retroactive disability tax credit calculator
Choose how many years back your approval reaches. Each year is valued at that year's own amount and rate.
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Counting back from 2026. Ten is the maximum the CRA will reassess.
How far back can the disability tax credit be claimed?
Up to ten prior tax years. Once the CRA approves your Form T2201 for an earlier period, it can reassess those returns and refund the credit for each year you owed tax. Every year is calculated at that year's own disability amount and credit rate, so the total is not simply one year multiplied by ten.
Ten years is the ceiling, not the default
The CRA can reassess up to ten prior tax years once the disability tax credit is approved for that period. That is a genuine ceiling and not an entitlement.
Your approval covers a specific period, decided by the CRA from the information your medical practitioner certified on Form T2201. If the practitioner indicated the impairment began four years ago, four years is what you get. Claiming a decade when your approval covers half that produces a very disappointing letter.
The other limit is your own tax history. The credit is non-refundable, so a year in which you owed no federal tax returns nothing, regardless of approval. Students, people on long-term benefits and anyone with several low-income years often find the real total well below the headline figure.
Why a flat multiplication is wrong
The obvious way to estimate this is to take the current credit and multiply by the number of years. That overstates it, for two separate reasons.
First, the disability amount is indexed and rises each year, so earlier years carry smaller amounts than today's. Second, the credit rate itself changed — it was 15% through 2024, then 14.5% for 2025 and 14% from 2026 as Canada cut its lowest personal income tax rate.
The calculator applies each year separately for exactly this reason. Where a year's amount is an indexed estimate rather than a confirmed CRA figure, the year is marked and the count is shown in the notes below the result.
How the total is built
One calculation per year, then summed.
credit for a year = that year's disability amount× that year's credit ratecredit rate: 15% up to and including 202414.5% 202514% 2026 onwardtotal = sum of every approved year in which tax was owedplus CRA refund interest on reassessed years
The CRA pays refund interest on amounts arising from a reassessment, calculated from the later of the relevant dates. That interest is not included in the figure above, so a real retroactive payment is usually somewhat larger than the raw credit total.
Requesting the adjustment is done through a T1 Adjustment Request or by asking the CRA to reassess the affected years when the T2201 is approved. There is no separate application fee.
Worked example: a five-year retroactive claim
Your T2201 is approved back to 2022, giving five eligible years from 2022 through 2026, and you owed tax in each.
- 2026: $10,341 × 14%$1,447.74
- 2025: $10,138 × 14.5%$1,470.01
- 2024: $9,872 × 15% (est.)$1,480.80
- 2023: $9,428 × 15% (est.)$1,414.20
- 2022: $8,870 × 15% (est.)$1,330.50
About $7,143 in federal credit across five years, before refund interest and before any provincial credit.
Note that 2024 produces slightly more than 2025 despite a smaller disability amount, because the credit rate was higher. That inversion is exactly what a flat multiplication misses.
Before you engage a service
A sizeable industry exists around retroactive DTC claims, typically charging a percentage of the refund — often 20% to 30%.
That can be worth it where a claim is complex or a practitioner needs chasing. It is worth considerably less where the paperwork is straightforward. Knowing the likely size of the claim before you sign anything is the point of an ungated estimate.
- The T2201 form is free and available directly from the CRA
- Your medical practitioner completes the certification, not the service
- The CRA can reassess prior years without a separate paid application
- Contingency fees are charged on the refund, including any provincial portion
- Ask what happens to the fee if the claim is approved for fewer years than hoped
Assumptions and limits
- Assumes you owed enough federal tax in every year shown to absorb the credit
- Amounts before 2025 are indexed estimates, not confirmed CRA figures
- The child supplement is approximated as a proportion of the base amount
- Excludes CRA refund interest, which is paid on top
- Excludes provincial credits, which vary by province and year
What has changed, and when
Rates on this page have not always been what they are today. If you are working on an earlier period, use the figure that applied at the time rather than the current one.
- From 2026 Credit rate 14%.
- 2025 Credit rate 14.5%, blended because the federal rate cut took effect on 1 July 2025.
- 2024 and earlier Credit rate 15%. This is why a retroactive claim is not one year's credit multiplied by the number of years — each year carries its own amount and its own rate.
Common questions
How far back can I claim the disability tax credit?
Up to ten prior tax years, provided the CRA approves your eligibility for that period. The approval period is set from the medical certification on Form T2201, so it may be shorter than ten years even if your impairment is longstanding.
How much is a ten-year retroactive DTC claim worth?
It depends on how much federal tax you owed in each of those years. As a rough guide, the federal credit has run between roughly $1,200 and $1,480 a year over the past decade, so a full ten-year claim with tax owing throughout might total somewhere near $13,000 to $14,000 before interest and provincial credits.
Do I get anything for years when I owed no tax?
No. The disability tax credit is non-refundable, so it reduces tax owing rather than paying out. A year with no federal tax payable produces nothing, which is why low-income years often make a retroactive claim smaller than expected.
Does the CRA pay interest on a retroactive refund?
Yes. Refund interest is paid on amounts arising from a reassessment, so the actual payment is usually a little larger than the raw credit total. That interest is not included in the estimate here.
Do I need to pay a company to claim retroactively?
No. Form T2201 is free from the CRA, your medical practitioner completes the certification, and the CRA can reassess prior years directly. Services exist and can be useful for complex claims, but they typically charge 20% to 30% of the refund.
Where these numbers come from
- Canada Revenue Agency — Claiming the DTC, including past years Confirmed 2025 amounts and the rules for claiming prior years.
- Canada Revenue Agency — Disability tax credit overview The T2201 process and how the approval period is determined.
- Department of Finance Canada — Delivering a middle-class tax cut The credit rate change to 14.5% for 2025 and 14% from 2026.
Last verified 2026-08-01 Rates on this page are checked against the sources above at least once a year, and whenever the governing authority announces a change. Spotted something out of date? Tell us and we will fix it.
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