Money questions, worked out to the cent.

FV = P(1 + r/n)^nt + PMT × ((1 + r/n)^nt − 1) ÷ (r/n)

P is the starting amount ($10,000), r the yearly rate (0.07), n how many times a year growth is added (12), t the years (30), and PMT the monthly deposit ($500).

1. The $10,000, left alone for 30 years, grows to $81,164.97.
2. The $500 deposits, each made at the end of a month, grow to $609,985.50.
3. Together: $691,150.47.

Assumes a steady 7% every year, before inflation and tax. Real markets do not move in a straight line.

savings needed = yearly spending ÷ yearly withdrawal rate

1. $40,000 ÷ 0.04 = $1,000,000.00.

The 4% figure is a rule of thumb drawn from studies of past US market returns. It is not a guarantee, and the calculator lets you change it.

1. Fund charging 0.05%: you end with $683,965.10.
2. Fund charging 1%: you end with $562,483.27.
3. The difference: $121,481.83, or 17.8% of what you would have had.

Both funds earn 7% a year before fees. The fee is taken off that return every year for 30 years.

1. Early-withdrawal penalty, 10%: $2,000.00.
2. Federal income tax, 22%: $4,400.00.
3. State income tax, 5%: $1,000.00.
4. $20,000 − $7,400.00 = $12,600.00.

Assumes the whole withdrawal is taxed at those rates and that none of the IRS exceptions to the penalty applies to you. US federal rules.

1. Smallest: balance ÷ life expectancy = $500,000 ÷ 36.2 = $13,812.15 a year.
2. Paid out like a loan at 6.11%: $34,592.01 a year.
3. Largest, using the IRS mortality table at 6.11%: $36,153.31 a year.

6.11% is the highest interest rate the IRS allowed as of November 2026; it changes monthly. The catch: in this example you must keep taking the same payment for 9.5 years. Change it early and the penalty comes back on everything you took.

1. Roth: $7,500 a year goes in, already taxed, and grows to $708,455.90. All of it is yours.
2. Traditional: the same take-home pay is $9,868.42 before 24% tax, so more goes in. It grows to $932,178.81.
3. Take 12% tax off that on the way out: $820,317.35.

Assumes 7% growth a year. If your tax rate in retirement were higher than today's, the Roth would win; if the two rates matched, the accounts would tie exactly.