Monthly Cash Flow Calculator
Quick check on monthly money.
Calculate monthly cash flow. Income minus costs and savings equals remaining. Enter fixed costs and variable costs for an instant result.
What this tool does
This tool calculates monthly cash flow remaining after fixed costs, variable costs, and savings. Shows surplus/deficit, total spending, and savings rate.
Enter Values
Formula Used
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Disclaimer
Results are estimates for educational purposes only. They do not constitute financial advice. Consult a qualified professional before making financial decisions.
Monthly cash flow is income minus all outflows (fixed costs, variable costs, savings) - the amount left over. Positive = surplus, negative = deficit. This calculator shows the figure plus savings rate and breakdown.
4,000 income with 2,000 fixed, 800 variable, 400 savings: 800 remaining, 10% savings rate. Healthy cashflow aims for 15-25% savings with positive remaining buffer. Negative remaining means monthly overspending - unsustainable without building debt.
The tool is quick but useful monthly. Track income, fixed (rent, bills, subscriptions), variable (food, entertainment, transport), savings set aside. Remaining is actual free cash. If negative, something's wrong with the budget structure.
Quick example
With monthly income of 4,000 and fixed costs of 2,000 (plus variable costs of 800 and savings set aside of 400), the result is 800.00. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.
Which inputs matter most
You enter Monthly Income, Fixed Costs, Variable Costs, and Savings Set Aside. Frequency and unit price pull the total in different directions. The biggest surprise for most people is how small recurring amounts compound into large annual figures — that's where this calculation earns its keep.
What's happening under the hood
Remaining = income - fixed - variable - savings. Savings rate = savings / income. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.
Revisiting the plan
Budgets are living documents. Re-run this whenever income changes, housing changes, or you notice a recurring overrun in a category. A budget from two years ago is probably already wrong.
What this doesn't capture
Budgets are snapshots of intent. Real spending includes irregular costs: birthdays, one-off repairs, the occasional bad week. Tracking actual spending for a month before fixing any budget usually reveals 10–20% that didn't make the original plan.
£4,000 £ - £2,000 £ - £800 £ - £400 £ = $800.00.
Inputs
This example uses typical values for illustration. Adjust the inputs above to match a specific situation and see how the result changes.
Sources & Methodology
Methodology
Remaining = income - fixed - variable - savings. Savings rate = savings / income.
References
Frequently Asked Questions
Is positive remaining good?
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