And if you have hundreds of thousands or millions in the traditional. The pro rata rule would make your backdoor contribution 90+% taxed so it would be pointless

The confusion here is that trad IRAs can be pretax or posttax dollars.

This rule only matters if you have pretax dollars in an IRA that you want to also use posttax dollars to backdoor.

To be clear, it wouldn't be taxed at 90% in this example. It's that 90% of the conversion amount would be taxed as ordinary income.

AFAICT there's no extra paying taxes here or anything. Your pretaxed dollars are being taxed, instead of posttax dollars not being taxed.

If you roll a 401k into an IRA, those will be pretax dollars in the IRA. It doesn't take a very big rollover to completely swamp the tax benefits of a 7k annual Roth contribution limit.

No. Pro rata is Latin for “in proportion.” It’s one dollar for one dollar. If you add $7k to your tIRA to do the backdoor Roth, you also must convert $7k of existing funds which becomes taxable income. So you pay your marginal tax rate, on half the amount.

IMO not that big of a deal to contribute $7k, convert $7k, and pay $2-3k in taxes to get $14k in the Roth space that will grow tax free forever. Most people are too pre-tax heavy in their retirement strategies anyway.

I'm not familiar with the strategy you're describing, but this is not how it works for the majority of backdoor Roth contributors.

If you have $100k pre-tax in a trad IRA, contribute 7k after tax for the purpose of rolling into a Roth, then you will owe income tax on the proportion of 100/107*7k, or $6,542.

You're still limited to 7k annual (for 2025) so the 14k you describe must be something else.

>The pro rata rule would make your backdoor contribution 90+% taxed so it would be pointless

All contributions or conversions to Roth IRAs are after-tax dollars.

The PITA of that is that you have to keep track of the post tax additions pretty much for ever afterward or you’ll end up paying double tax on them.