Financial tools
Standalone calculators that run entirely in your browser - nothing you enter leaves your device. They complement the retirement planner: where the planner models your whole financial life, each tool answers one specific money question well.
Price a synthetic loan built by selling an SPX box spread - borrow against portfolio margin at near risk-free rates instead of taking a consumer loan, e.g. to buy a car without an auto loan.
The all-in cost of buying a nice car, driving the bucket-list road trip, and selling it: depreciation, loan interest, insurance, running costs, and inflation, with a cost curve for every possible sale month.
How much to set aside in an account to raise a child to 18: age-banded yearly costs with inflation and investment growth, answered as a lump sum today or a level monthly contribution.
Amortization with recurring extra and one-time payments: interest and months saved vs the contractual schedule, shown in nominal dollars and deflated to today's purchasing power.
Whether paying a jumbo mortgage down to the $750k interest-deduction cap beats keeping the money invested: the never-deductible slice above the cap, the standard-deduction hurdle, the month-by-month net-worth race, and the breakeven return that decides it.
Fill the low tax brackets with Roth conversions each year of early retirement - the tax on every rung after deductions, when each rung unlocks under the 5-year rule, and whether the seasoned money can pay off the mortgage years early.
How much money you need outside the retirement accounts to live on while a Roth conversion ladder seasons: the five-year gap before the first rung, the conversion tax the bridge also has to carry, the gains a conversion pushes out of the 0% bracket, and the smallest bridge that reaches 59½.
Every subscription, bill, and yearly fee in one list: monthly and yearly totals broken down across eight categories, with a suggestion catalog of popular expenses and an inflation projection calibrated per country - flat or per category.
A century of daily market data, fully offline: browse indexes, S&P sectors, gold and CPI with high-low detail, compare them rebased, and replay any buy/sell list against inflation, gold, or the S&P 500.