Basic calculator: COLA is applied equally to both benefits from when each starts collecting — so the relative monthly difference grows slightly over time, helping the delayed option catch up a bit faster than the no-COLA formula.
Investment calculator: Assumes you invest every early payment at the stated annual return. "Portfolio built" is the compounded value at the delayed start age. The annual portfolio return vs extra SS income shows whether the portfolio advantage can ever be overcome. At high return rates, the investment may earn more than the extra SS income each year — making break-even essentially never.
Survivor benefit notes: Survivor FRA assumed age 67 (born 1962+; use 66 if born 1945–1956). Survivor rate rises linearly from 71.5% at 60 to 100% at FRA per SSA formula. If the worker's benefit was reduced for early claiming, that reduced amount is the survivor's ceiling.
Not modeled: Taxes on SS (up to 85% may be taxable), Medicare Part B premiums (~$185/mo deducted), COLA on survivor benefit projection. For planning purposes only.