Spousal contributions are limited to the lesser of:

• The annual contribution limit ($6,500 for 2023) plus an additional $1,000 if aged 50 or older or
• The couple's combined eligible compensation reduced by any contributions made to the compensated spouse's Traditional or Roth IRA.

A couple's maximum combined contribution amount is $13,000 for 2023 ($15,000 if both spouses are age 50 or older), assuming they have enough combined compensation to make the maximum combined IRA contribution.