How a crypto portfolio is measured
Tracking a portfolio means holding two numbers for every position: what it is worth now, and what it cost you. The difference is unrealised gain — real on screen, but not banked until you sell. Realised gain is what you actually locked in on disposals, and it is the figure that usually matters for tax and for judging whether a strategy worked.
The other half of the picture is weighting. A position's percentage of total value tells you how much of your outcome it controls. Most people badly misjudge this, because they think in terms of what they bought rather than what it grew into — the winner that ran hardest is quietly now the position that decides everything.
Cost basis tracking is the unglamorous part that people regret skipping. Every buy, swap, fee and transfer changes it, and it has to be maintained per position rather than as one running total. Reconstructing years of activity from partial exchange exports after the fact is far harder than recording it as you go, and exchanges do not keep history forever.
Worked example
A three-asset portfolio: 0.4 BTC bought at 45,000 and now at 64,000, 5 ETH bought at 2,400 and now at 3,200, and 60 SOL bought at 120 and now at 150.
| Input | Value |
|---|
| BTC — value / weight | 25,600 / 50.6% |
| ETH — value / weight | 16,000 / 31.6% |
| SOL — value / weight | 9,000 / 17.8% |
| Total portfolio value | 50,600 |
| Total cost basis | 37,200 |
| Unrealised gain | 13,400 |
| Return on cost | 36.0% |
BTC is barely over half the portfolio, which sounds balanced — but a 20% move in BTC alone shifts the whole portfolio by 10.1%, more than the other two assets combined could manage. If your target weight for BTC were 40%, restoring it would mean trimming 5,360 of it.
How to use this calculator
- Enter each holding with the quantity you actually hold and the price you actually paid, fees included.
- Add the current price for each asset to get position values and weights.
- Read the weight column first — it tells you what is really driving the portfolio.
- Compare unrealised gain against cost basis for the return figure, rather than judging by the absolute number.
- Record disposals separately as they happen so realised gains and cost basis stay accurate for tax.
Frequently asked questions
What is the difference between unrealised and realised gain?
Unrealised gain is the paper difference between current value and cost basis on something you still hold — it moves every day and can disappear. Realised gain is locked in by an actual disposal. Most tax systems care about the second, not the first.
How much concentration is too much?
There is no universal number, but a useful test is to ask what happens if your largest position halves. If that outcome is unacceptable, the position is too large for you regardless of how confident you are in it. Concentration is what makes portfolios and what breaks them.
Why does cost basis matter so much?
It determines your gain on every disposal, and therefore what you may owe. It also changes with fees, swaps, airdrops and transfers between your own wallets. Rebuilding it years later from partial exchange records is genuinely difficult and often produces a worse answer than you would have owed.
When should I rebalance?
Two common triggers are calendar-based — a fixed review each quarter — and threshold-based, where you act only when a weight drifts a set number of percentage points from target. Threshold rules trade less and avoid rebalancing for its own sake, but require you to actually check.
Should stablecoins count as part of the portfolio?
Include them, but track them as their own allocation. Treating stablecoins as invisible cash hides the fact that you may be far less exposed to the market than you think — or, after a drawdown, far more.
Does moving coins between my own wallets affect anything?
It does not change what you own, but it costs network fees and it fragments your records. Many jurisdictions do not treat a self-transfer as a disposal, though the fee itself may be treated differently. Keep the transfer logged either way so balances reconcile later.
This calculator is an educational tool. Results are estimates based on the inputs you provide and do not constitute financial advice. Verify figures with your bank, broker or a qualified advisor before acting on them.