I think it is fine to just give a broad, vague hint, without making it seem like there are even financial problems. Probably something along the lines of managing money better. But not to tell him about the true nature of the problem. Reason: I don't think it is good for a kid's developing psyche to inform him of the full extent of your problems as it will erode his self-confidence and feeling of security, which will follow him into adulthood. As much as we wish that our children learn not to derive self-confidence from having money, we cannot deny that it does affect confidence. I think I saw an article once about how it affects children into adulthood, causes them to present themselves differently and make different decisions. So im not saying don't tell him so as to spare his feelings, but rather don't tell him so that his mental development will not be adversely affected in the long run. If he persists in asking, just tell him you both recently did a review of your finances and felt that the family as a whole could afford to cut back on expenses generally, in order to prepare for the future or any emergencies.