As seen in 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. In this case, it means your tuition credit has already been used and applied. You don’t have further tuition to carry forward and there is no carry forward tuition to be applied in your current tax return."
If you already filed your 2020 tax return and got the assessment from the CRA, you could know your final tax amount which you have to pay for your tax owed. If you still have an owed amount, it means there is no more non-refundable tax credit (tuition credit) to be applied in your 2020 tax return.
For more information, this link below from our website will be useful.
Understanding Tuition Tax Credit.
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