Is there a limit to the amount of caps you can have?

Solution 1:

Congrats on being a super rich vault!

Vaults can hold a maximum of 999,999 caps. Any more you collect from production rooms, level ups, exploring the wasteland, selling items, or anything other than lunchboxes will not increase your caps beyond 999,999.

As with all other lunchbox related things, lunchboxes ignore the cap on caps. Any cap cards you pull from a lunchbox (x100, x500, etc) will add their full amount of caps to the total, even if it puts you over 999,999.

You will accumulate caps normally again once you spend enough caps for your total to drop below 999,999.