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The amounts of unused credit are applied to reduce tax payable automatically. The Canada Revenue Agency (CRA) applies the available tuition amount carried forward every year to reduce your taxes to zero until it has all been used. You don't need to include the unused amounts, CRA will do that automatically.
However, if you forget to claim tuition fees from 2018, you cannot claim this amount in your 2020 tax file. You should amend the prior year's return, claim the credit in that year, and then calculate any unused amounts that you’re allowed to claim this year. While CRA adjusts both 2018 and 2019 returns, you can wait for reassessment for both years before adding anything to the 2020 tax return.
According to the TurboTax article: "The amounts of unused credit are applied to reduce tax payable automatically. The Canada Revenue Agency (CRA) applies the available tuition amount carried forward every year to reduce your taxes to zero until it has all been used."
To see if you have any unused tuition amount left, you can verify your information on the Canada Revenue Agency My Account for Individuals.
For more information, this TurboTax article below from our website will be useful.
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