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@ pelu
2025-05-07 21:17:02
I made a retirement calculator where you perpetually borrow from your bitcoin and never sell. Instructions in thread.
https://www.desmos.com/calculator/880nh6wfmi
CALCULATOR OBJECTIVE
Evaluate the viability of funding your entire retirement living expenses through a loan, using your Bitcoin holdings as collateral. The loan balance increases annually as you borrow to cover both your living expenses and the interest required to service the loan. This strategy is considered successful if the value of your Bitcoin grows at a faster rate than your loan balance, ensuring that the loan-to-value (LTV) ratio remains manageable—typically below 50%.
CALCULATOR INPUTS
Adjust the following inputs using the sliders on the left-hand side:
(R): The year you retire—assumed to be January 1st of this selected year.
(M): Your desired income in the first year of retirement (R). This amount increases annually by F.
(F): The inflation rate or the percentage by which you want your income to grow each year.
(L): The annual interest rate on the loan—the cost of servicing your debt.
(B): The amount of Bitcoin you are using as collateral for the loan.
(P): Adjusts the Bitcoin price projection. Refer to this chart* for guidance:
- Enter 0.42 to follow the red support line—a conservative price projection.
- Enter 1 to follow the green trend line—an aggressive price projection.
*https://charts.bitbo.io/long-term-power-law/
CALCULATOR GRAPH
This graph displays the results of your calculations, with the x-axis representing years and the y-axis representing USD. Each colored line represents a key financial metric over time:
Green Line – Your income growth throughout the years.
Red Line – Your loan balance as it increases annually.
Orange Line – The value of your Bitcoin collateral over time.
Blue Line – The loan-to-value (LTV) ratio, scaled for visibility. (Note: The LTV is artificially multiplied by 10⁹ for display purposes; divide by 10⁹ to obtain its actual value.)
EXAMPLE
Consider a conservative and frugal individual holding 3 bitcoins, planning to retire in 2026 with an annual living expense of $35,000. Assuming an inflation rate of 7% and a loan interest rate of 10%, the input parameters are as follows:
R = 2026 (Retirement Year)
M = 35,000 (Initial Annual Income)
F = 0.07 (Inflation Rate)
L = 0.10 (Loan Interest Rate)
B = 3 (Bitcoin Collateral)
P = 0.42 (Conservative Bitcoin Price Projection)
Now, does this strategy hold up? Based on the calculator’s results:
- The loan-to-value (LTV) ratio peaks at 47% in 2030, then decreases over time, indicating the loan remains viable.
- 30 years into retirement, the loan balance reaches approximately $13 million, while the value of the Bitcoin collateral grows to around $56 million.
According to the numbers, this approach appears feasible—provided the individual is comfortable managing a high level of debt throughout retirement.
ADVANCED
All the formulas are visible and easy to modify if you wish to.