From 2009-2015, I was studying in Ontario universities, and made no income. My parents paid all my tuition. I filed my taxes, but didn't know that I could claim tuition tax credits.
You don't have any tuition credit currently available for the years that you did not file. This alone is worth filing past years. Unless you want to just toss the possibly $10k in future refunds.
Can I claim this full amount this year?
You need to refile each of those previous years. Even though they carry forward, they have to be claimed in the year you pay.
How much of a tax credit can I expect?
(Value of credits) * 0.15
You might also get provincial refunds depending on your province.
For the years prior to 2017, you will also get tuition and education monthly amounts.
Is the maximum tuition tax credit $5000 CAD?
Do I understand u/Drithaan's comment beneath? As I spent more than $33,333 (= 5000/0.15), my parents can pay less tax if I retroactively transfer the credit from each year to my income-earning parents. Right?
You can carry forward all of your unused tuition credits from post-secondary. Transferring them to a parent counts as using them, so if you've been doing this you will have less to carry forward.
This weekend, I'll refile my taxes from 2009-2013, as u/bluenose777 commented in 2018
3/ You can amend returns for 10 years so currently that means 2008 to 2017.
But have I missed and lost out on lowering my parents' taxes? Retroactively, can I transfer my tuition tax credits to my parents? Then my parents amend their tax returns too?
u/bubbles1286 in 2016
No, unfortunately tuition tax credits can only be transferred to others in the year they are paid. Past years' credits will sit on your account until you have the income to use them.
u/UnfortunateLuka in 2016
If these tax credits are from 2014 or earlier, no. Credits can only be transferred in their effective tax year. 2015 credits can only be transferred to a spouse this year.