Input Explainer

Current Age: Age today, in years (decimals ok).

FRA: Full Retirement Age from SSA (≈66–67).

PIA: Monthly benefit at FRA from SSA (today’s dollars).

Already Claiming? If a spouse is already receiving benefits, tick the box and enter their current monthly benefit (today’s amount).

Expected Lifespan: Planning age; benefits stop once reached.

Discount Rate (%): Real discount (use 0–4% typically).

COLA (%): Expected CPI/COLA.

Nominal valuation (grows benefits by COLA before/after claim and discounts at nominal = (1+real)*(1+COLA)-1).
Monthly simulation; no survivor benefits, restricted applications, child-in-care/family-max/earnings-test.
For singles, set Spouse B PIA to 0.