The gain the exchange rate made for you
Your capital gain is a Canadian-dollar figure, and each side of the trade converts at the rate on its own date. The consequence people find surprising is that a US-listed holding whose price never moved can still produce a real, reportable gain. Put your two dates in and see how much of the answer was the security and how much was the currency. It runs in your browser. Nothing you type is sent anywhere, and nothing is saved when you leave.
- Cost base
- $10,324.91
- Proceeds
- $16,951.15
- Gain in Canadian dollars
- $6,626.24
Converted at the purchase date’s rate.
Converted at the sale date’s rate.
In US dollars it is US$4,142.60.
What moved, and which part of it was currency
- The security moved
- $5,348.81
- The currency moved
- $1,304.06
- Change in value
- $6,652.88
Those two account for the whole change in what the position was worth in Canadian dollars. Your gain differs from it by the $26.64 of commissions, which are a cost rather than a market move and so have no security or currency half to split into.
How it calculates
The cost base is the purchase, plus its commission, converted at the purchase date’s rate. The proceeds are the sale, less its commission, converted at the sale date’s rate. The gain is the difference. Converting the whole position once, at today’s rate or at a year-end rate, gives a different and incorrect number.
The split underneath measures the price move at the opening rate and the rate move at the closing price. Those two account for the entire change in what the position was worth in Canadian dollars. Where both moved at once, that overlap is counted in the currency half. It is a convention rather than a fact, it is the same one the Luum app uses on its own attribution screens, and pnpm guard:currency-agrees fails the build if this page and the product ever split it differently.
Commissions sit outside that split, because a commission is a cost rather than a market move and has no security or currency half to divide into. So the change in value and the gain differ by exactly the commissions, and both are shown rather than reconciled into one tidier number.
What this deliberately does not do
- It publishes no exchange rate. The Bank of Canada publishes the daily rates and its page is the authority. A rate republished here would be a copy that goes stale without telling anybody.
- It is one purchase against one sale, not a cost base. Canada pools identical property per taxpayer, each purchase at its own rate, and a partial sale is measured against that average. That is the adjusted cost base calculator, and it is the tool to use if you have bought more than once.
- It does not know about your other accounts. If you hold the same security at a second institution, the two positions share one cost base. See adjusted cost base across two brokerages.
- It does not check the superficial loss rule. A loss can be denied if identical property was bought back within 30 days either side of the sale. See tax-loss selling.
Educational only, and accurate to what you enter. For how Luum separates currency from performance across every holding you own, see portfolio returns.