How the Mega Millions Payout Calculator works
Every Mega Millions jackpot can be claimed two ways: a smaller lump sum paid immediately (the "cash option"), or the full advertised jackpot spread across 30 graduated payments over 29 years (the "annuity option"). This calculator applies the standard structure behind both, then subtracts estimated federal and state withholding so you can see a realistic net figure for whichever option you select.
The annuity formula
The annuity pays the advertised jackpot J as 30 payments, each 5% larger than the one before it. That makes the 30 payments a geometric series, so the first payment P₀ solves J = P₀ × (1 + 1.05 + 1.05² + … + 1.05²⁹):
P₀ = J × 0.05 / (1.05³⁰ − 1)
Payment number n (counting the first payment as n = 0) equals P₀ × 1.05n, so the final, 30th payment is roughly 4.1 times the first one. The 30 nominal payments sum back to the full advertised jackpot.
The cash (lump sum) formula
The cash option is simpler: it is the advertised jackpot multiplied by a cash value percentage that the lottery sets before each drawing, based on prevailing interest rates and bond yields. Cash value = Jackpot × cash value %. That percentage has typically run 50-65% of the headline jackpot in recent years — it is the present-day amount the lottery would need, invested today, to fund the full annuity, which is why it is smaller than the annuity total.
Applying taxes
Lottery winnings are ordinary taxable income. The IRS requires lottery operators to withhold 24% of any win over $5,000 for federal tax automatically, but the mandatory withholding is not the final bill — winners in the top bracket typically owe closer to 37% once they file, which is why this calculator defaults the federal rate to 37%. States tax lottery winnings differently: some (like Texas and Florida) charge no state income tax, while others charge 5-11%. Enter the rates that apply to your situation; this tool applies them as a flat percentage of the gross payout to estimate net proceeds and does not model brackets, deductions, or credits.
Worked example
For a $500,000,000 jackpot with a 52% cash value: the cash option pays a gross $260,000,000. At 37% federal and 5% state tax, that is $96,200,000 federal and $13,000,000 state, leaving a net cash payout of about $150,800,000. Choosing the annuity instead pays out the full $500,000,000 nominal total across 30 payments, starting at roughly $7.5 million in year one and rising to about $31.0 million by year 30 — before the same tax rates are applied.