In 2023, you will be able to make a full Roth IRA contribution as a single if you make less than $138,000 per year. However, if you are married and file jointly, you can only make a full Roth IRA contribution if you and your spouse make less than $218,000 per year, which is less than 2 times $138,000 (which would be $276,000). Why is this? It seems unfair to married couples. You can still do a backdoor IRA, right?
Why is this?
Because the basic assumption of the lawmakers is that there's a breadwinner and a housewife. Under that assumption, any increase of limits would be beneficial since the income doesn't change with the marital status.
It seems unfair to married couples
Yes. This is called a "marriage penalty". The more the "other" spouse earns - the higher the penalty.
You can still do a backdoor IRA, right?
Yes. You can still contribute to a traditional IRA without claiming deduction, and then if you want - convert into Roth. Use form 8606 to track non-deductible IRA contributions. Worth reminding that there are pro-rata rules for IRA conversion that may make it partially taxable if you have IRA balances with gains or deductible contributions. Backdoor Roth IRA works best if you start and end every year with $0 balance in your traditional IRA (across all the custodians).