Why future-value math beats vibe-based projections
Most crypto investors anchor on a dream price — "Bitcoin at $1M," "ETH at $20K" — without doing the compounding math that connects today to that future. A future value calculator forces you to state the annual return you actually expect, then lets compounding do its work. The difference between 15% and 30% annual returns over 15 years is not double; it is more than 6x. Pick your CAGR carefully, because small changes at the input become enormous at the output.
This calculator uses the standard future value formula: FV = PV × (1 + r)^n, where PV is your current holdings value, r is the annual return, and n is the number of years. We then discount by inflation to show what that future number is worth in today's buying power — usually a sobering adjustment.
What CAGR should I plug in?
Bitcoin's rolling 10-year CAGR has been exceptional — in the 50-70% range — but that is largely because Bitcoin was an order-of-magnitude smaller a decade ago. As market cap grows, returns compress. Most institutional models forecast 15-30% annualized for the next decade, with wide variance. Ethereum has tracked similarly, with additional upside from staking yield. For altcoins, use 0-20% unless you have a strong thesis; most fail.
A useful exercise: run the calculator with three scenarios — bear (-5% CAGR), base (15%), and bull (35%) — to see the range of outcomes. If your retirement plan only works in the bull case, your plan is fragile.
Inflation is not optional
A $5M portfolio sounds like retirement money — until you remember that at 3% inflation, $5M in 20 years buys what $2.77M buys today. At 5% inflation, it buys $1.88M. Nominal returns are the headline; real returns are the reality. If your crypto grows 10% a year and inflation is 4%, your real return is 5.8% (not 6%, because of compounding).
For anyone using crypto as a long-horizon store of value, inflation is the whole point. Compare your expected real return against the real return of stocks or stablecoin yield before concluding crypto is the right bucket.
The compounding trap
Compounding works both ways. A -50% year followed by a +50% year does not get you back to flat — it leaves you at 75% of where you started. Crypto's volatility means your realized CAGR will almost always be lower than the average of your annual returns. This is why professional investors report geometric means (CAGR) rather than arithmetic averages. When you hear "average 40% annual returns," ask what the CAGR was — it's usually 10-20 percentage points lower.
Position sizing matters more than return
If you have 1% of your net worth in crypto and it 10x's, you now have 10% — a meaningful allocation but not life-changing. If you have 20% in crypto and it 2x's, you moved your total net worth 20%. Run this calculator against your full net worth, not just your crypto stack, to see whether the outcome actually matters. Then size accordingly. Pair this with our portfolio rebalance tool to keep your crypto allocation in range.
Tax drag is the silent killer
A 25% long-term capital gains rate (federal + state in a high-tax state) reduces a 10x return to about 7.75x net. A 37% short-term rate cuts it to 6.7x. If you plan to trade actively, your effective CAGR can be 30-40% lower than the headline. Long-term buy-and-hold is almost always more tax-efficient — and almost always beats active trading after fees and friction. Use our crypto tax calculator to model the tax hit before you sell.
When to revisit your assumptions
Every 12-18 months, re-run this calculator with updated price, updated holdings, and updated return expectations. If Bitcoin just went up 3x, your forward CAGR should probably be lower — returns tend to mean-revert. If it just went down 60%, forward CAGR may be higher (cheaper entry). Good investors update their priors; bad ones anchor on the thesis they had five years ago.
What this calculator does not include
Exchange risk, custody risk, regulatory risk, protocol risk — none of these are in the math. A 10x return that you cannot access because your exchange froze withdrawals is a 0% return in practice. Use hardware wallets for long-term holdings, diversify across custodians, and assume any single venue has a non-zero chance of going to zero over a 10-year horizon.