Practical money guide
For flat expenses, divide available savings by monthly expenses minus dependable income. If expenses change, project each month's balance instead of relying on one fixed ratio.
Start with money assigned to the period you are modeling. Deduct known one-off commitments first. Keep a separate emergency reserve if you do not intend to spend it during the transition. Do not count an unpaid invoice or a possible asset sale as cash without explicitly testing the delay.
At $2,800 of expenses and $600 of income, the balance falls by $2,200 each month if costs stay flat. A $30,000 reserve then lasts 30,000 ÷ 2,200, or about 13.64 months. The model treats monthly income as constant; change it to zero to see a more conservative case.
The calculator's default 3% is annual expense growth, converted to a monthly rate. It increases expenses while income stays fixed. Under those assumptions, the same reserve lasts about 13.37 months. Set burn change to 0% to reproduce the simple ratio, then test a higher rate rather than assuming one projection will hold.
Running out of cash is usually too late to change course. Choose a remaining balance or number of months at which you would look for income or reduce spending. With growth set to zero, reducing expenses from $2,800 to $2,300 extends this example to about 17.65 months. That buys roughly four months, but the feasibility of the cut remains your decision.
Live model
Enter your assumptions to see an estimate. Use source view to inspect or change the calculation. Your inputs stay in this browser.
template: runway savings = 30000 in usd monthly_burn = 2800 in usd monthly_income = 600 in usd burn_change_rate = 3%
Inputs
Method
net_burn = monthly_burn - monthly_incomesimple_runway = starting_cash / net_burnchanging-burn runway is found by projecting each month until balance ≤ 0The inputs and source use the same model. Open it in Continuum for a document you can keep and revisit.
Worked example
The useful question is not only the depletion month. It is when to cut costs, replace income, or stop treating the current plan as safe.
Questions
Flat expenses would not deplete savings. Growing expenses can still lead to depletion later. The calculator distinguishes the modeled horizon from a guarantee that money lasts forever.
No. The runway model tracks cash expenses and income. Use the investment calculator separately for growth assumptions rather than treating uncertain returns as spendable cash.
The projection steps through months and estimates the fraction of the final month covered by the remaining balance. Real bill dates can make practical cash availability differ.
Keep the reasoning
The full template opens as a local Continuum document. Edit every assumption, explore the result breakdown, and keep the source.
Open how long will my savings last?