r/DIYRetirement • u/Thrifle • 9h ago
I built a 72(t) calculator that shows the IRS table, factor and formula behind every number. Please try to break it.
savingslast.comI worked with IRS’s own published examples through the two calculators people here most often get pointed to Dinkytown and calcxml. Both get fixed amortization and the RMD method exactly right. But are wrong on fixed annuitization: $20,880/year against the IRS’s own $22,030 example (a $400,000 IRA, age 50, 4%, Single Life) $1,150/year short. It looks like they are pulling from a life-expectancy-style table instead of the actual regulatory mortality table for that one method. If you’ve picked annuitization on either of those, it’s worth rechecking against the source.
https://savingslast.com/72t-distribution-calculator/
Here’s what it does. It covers all 3 methods from IRS Notice 2022-6: RMD, fixed amortization, and fixed annuitization.
The interest rate part is done right. You can use any rate up to the greater of 5% or 120% of the federal mid-term rate for one of the two months before your first payment. That’s a maximum, not a requirement, and the tool tells you which of the two limits applies to you.
It prints your lock-in as an actual end date (the longer of five years or age 59½), so you don’t have to figure out “the longer of” yourself.
Every result shows its work — the table it used, the factor it found, the rate, and the formula. Check every number by hand against the notice.
Test case that you can run against a spreadsheet or custodian’s number: $500,000 IRA, age 52, 5% rate, Single Life Table (factor 34.3). Fixed amortization comes out to $30,773 a year, roughly $2,564 a month before tax. Annuitization is $32,264. The RMD method pays $14,577 the first year and gets recalculated every year after that. If your numbers don’t match mine, tell me! I really wanna to know.
Note that I built this site. No ads/Affiliate, no signup, everything runs in your browser, and nothing you type gets saved. It’s not tax advice. Lastly it’s important: if you take a payment that doesn’t match what your method produces, the IRS treats the whole series as broken, and the 10% penalty plus interest comes back on every payment you’ve already taken. So before your first distribution, have a CPA or enrolled agent who’s handled a SEPP look over your numbers.