Your RMD for 2025 is based on the value on Dec 31, 2024 divided by your life expectancy according to IRS tables. For example, if your life expectancy is 20 years, your RMD for 2025 would be 1/20th the balance as of 12/31/24.
The easiest way to know what that is is to ask your retirement plan. They have the formulas, and probably have an online calculator. (It depends, in part, on your age, and your spouse's age if you are married.) The formulas are in the appendix of Publication 590-B, if you want to figure it yourself. But easier to ask the plan.
https://www.irs.gov/pub/irs-pdf/p590b.pdf
