As part of the T2125 form - see link above to get to it easily. There is a section for CCA - you put in the total price in box one and then just follow the math in each box even if it makes no sense to you - it does when you think about it at the end but not when you are doing it. Basically because only 50% of the total price is claimable in the first year so you end up with 20% of half the cost of the item for year one but then in future years it is 20% of the whole remaining amount ( a good tax strategy is to buy a lot of stuff in Nov/Dec instead of waiting till Jan). The boxes then give you the amount to transfer to the tax form and the amount you will use next year so keep that figure - ie write it down somewhere for easy access.