Compare the cumulative direct dollar cost of self-custody (hardware wallets, estate planning, insurance allocations) against the cost of custodial Bitcoin storage (basis-point fees on a growing balance) over a multi-decade horizon. The calculator models direct costs only and does not weight the probability-adjusted cost of operational failure in self-custody.
Under these assumptions, the dollar difference reflects the trade-off between basis-point custodial fees on a growing balance and the more static cost structure of self-custody (hardware + estate planning + insurance allocation). Self-custody savings scale with balance growth; custodial fees scale with balance growth.
Cheaper is not the same as safer. Self-custody shifts operational responsibility to the holder. Industry estimates of permanently lost Bitcoin attribute meaningful portions of historical loss to self-custody operational failures. The calculator models direct dollar costs, not the probability-weighted cost of operational failure.
The self-custody annual ops cost should include allocated estate planning attorney fees, hardware wallet insurance, secure storage (safe deposit box, home safe), and the holder's time. Hardware wallets typically last 5-10 years; replacement intervals affect the amortized cost.
Custodial fees compound on a growing balance; self-custody costs are relatively static. The break-even point shifts with growth rate and holding period.