How the cash reserve model works
Let E be essential monthly expenses, m your chosen coverage months, S cash available now and C your planned monthly cash addition. Target = E × m. Shortfall = max(0, target − S). Excess = max(0, S − target). Current expense coverage = S / E when E is greater than zero; it is not calculated when E is zero.
With a positive gap and monthly addition, time to fill = ceil(shortfall / C) months. Each completed month adds C with no interest. Zero additions cannot fill a positive gap; if cash already meets the target, time to fill is zero. Expenses and planned additions stay fixed.
Illustrative example: monthly expenses 3,000, chosen coverage 6 months, available cash 5,000 and monthly additions 500 give a target of 18,000, a shortfall of 13,000, no excess and 26 months to fill. Current cash covers about 1.67 months of entered expenses. Six months is an editable illustration, not a recommendation for everyone.
Educational calculations, not financial advice. You choose the expense estimate and coverage period; this tool does not recommend a reserve size or assess employment security or risk. It does not recommend investing emergency cash in stocks, count a projected investment balance as available cash, or model interest, inflation, taxes or changing expenses.