Your NPC results should be viewed as a good estimate, in my opinion. But they also need to be done at the right time.
Right now, the NPCs are set for kids starting college fall 2025…this year. Using info from tax year 2023.
For those of you with HS juniors, these are NOT set for when your kids will be going to college. Most schools adjust their NPCs late summer just prior to your kid’s senior year in HS.
Also, you will note that some NPCs are more “robust” than others, asking more questions. Those tend to be more accurate.
I personally would not use a third party calculator except as a VERY rough estimate…but that is my opinion.