I Want My MTG
If you have ever opened the Portfolio page and wondered where the numbers come from, this post is for you. We will walk through each line on the page, in the order it shows up, and explain what it means and where the math comes from.
The two inputs
Everything on the Portfolio page is built from two things:
- Your inventory. What you currently own, in what quantity, foil or non-foil.
- Your transactions. A log of every buy and sell you have recorded, including the price you paid or received.
Inventory tells us what you own right now. Transactions tell us what it cost to get there. You can use the app with only inventory and skip transactions entirely, but then we cannot calculate cost basis or profit and loss for you. The Portfolio page leans on both.
Current value
The easiest number. We take every card and sealed product in your inventory, multiply each by its current market price, and add them up. Foil and non-foil are valued separately. If a card has no price (a recent spoiler, for example), it contributes zero.
This is the number you see in the headline. It moves every day as prices update.
Total invested (cost basis)
This is the sum of every buy transaction you have ever recorded, with one twist: when you sell a card, we have to decide which copy you sold.
We use FIFO, short for first-in, first-out. The oldest copy you bought is the first one we count as sold. Say you bought one copy of a card for $5 in January and another for $20 in March. If you sell one copy in May, FIFO says you sold the January copy. Your remaining cost basis for that card is $20, not $12.50 (the average) and not $5 (the most recent).
FIFO is the standard method most accountants reach for, and it tends to match how collectors actually think about their cards. The oldest copy is the one you have lived with the longest, so it is the one most likely to leave the shelf first.
Unrealized P&L
This is the gain or loss on cards you still own.
Unrealized P&L = Current value of held cards - Cost basis of held cards
“Held” is the key word. Sold cards do not show up here. If a card has doubled in price but you have not sold it, the gain is unrealized: real on paper, not yet in your pocket.
Realized gains
The flip side. When you record a sell transaction, we subtract the FIFO cost basis of the copies you sold from the price you received. That difference is your realized gain (or loss) for that sale. The Portfolio page sums them across every sell you have logged.
Realized gains are locked in. They do not move when prices move, because the sale already happened.
ROI
Return on investment, as a percentage:
ROI = (Current value + Realized gains - Total invested) / Total invested
A positive ROI means your collection (sold and held combined) is worth more than you spent on it. A negative ROI means the opposite. It is a single number that bakes in both unrealized and realized performance.
Why your numbers might look off
A few things trip people up:
- You logged sells without buys. FIFO needs a buy to draw from. If you sell a card you never recorded buying, the cost basis is zero and the gain looks artificially large.
- You imported inventory but not history. A bulk inventory import gives us the “what you own” picture but no purchase history. Cost basis and P&L will only reflect transactions you logged after the import.
- A card has no current price. Recent spoilers, obscure printings, and some promos have gaps in price data. They count as zero in current value until a price shows up.
You do not have to record every transaction to use the app. But the more complete your transaction log is, the more useful the Portfolio page becomes.
Where to go from here
If you have inventory but no transactions, the fastest path to a real Portfolio number is to log buys for your most valuable cards first. Even rough purchase prices give you a baseline. You can refine later.
If you have questions about a specific number on your own Portfolio page, the Discord linked in the footer is the place to ask.