A monthly figure from a quarterly schedule
Almost every US dividend stock and ETF pays quarterly, so the monthly number this calculator reports is an average rather than a schedule. A portfolio paying $6,000 a year shows here as $500 a month, but it will really arrive as three lumps. That distinction matters if you are budgeting against it: the average tells you whether the portfolio is big enough, and the payment calendar tells you whether you need a cash buffer to smooth the gaps.
You can flatten the calendar without changing the total. Holding funds with staggered payment months (one paying January, April, July, October, and another paying February, May, August, November) produces something close to a monthly paycheck out of quarterly payers. It is a scheduling trick, not extra income, and it is not worth accepting a worse fund to achieve.