FinToolSuite

Cash Flow Calculator

Updated April 18, 2026 · Financial Health · Educational use only ·

Cash position forecast.

Project ending cash and runway from starting balance, inflows, and outflows. Enter starting cash and cash inflow for an instant result.

What this tool does

This tool forecasts cash position month by month from starting cash, monthly revenue, monthly expenses, forecast period, and revenue growth rate.


Enter Values

Formula Used
Starting cash
Monthly inflow
Monthly outflow
Forecast period

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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.

Cash flow forecasting projects month-by-month what's in the bank, spotting shortfalls before they happen. Start with current cash, add monthly revenue (growing over time), subtract monthly expenses. The result shows ending cash each month and the lowest point along the way - the 'cash valley' that signals when overdraft or funding is needed.

50k starting cash with 20k monthly revenue and 22k monthly expenses burns 2k/month. Without growth, that's 24k/year burn, hitting zero in 25 months. Add 10% annual revenue growth and the business becomes cash-positive around month 12, ending year 1 at 56k.

Most small businesses fail from cash flow, not profit. A profitable business with 60-day customer payment terms and 30-day supplier terms can run out of cash while booking record revenue. This tool doesn't solve cash timing within a month, but the month-level forecast catches the bigger problem: whether you're heading toward an empty account.

Run it with sensible defaults

Using starting cash of 50,000, monthly revenue of 20,000, monthly expenses of 22,000, months to forecast of 12 months, the calculation works out to 37,311.36. Nudge the inputs toward your own situation and the output recalculates instantly. The defaults are meant as a starting point, not a recommendation.

The levers in this calculation

The inputs — Starting Cash, Monthly Revenue, Monthly Expenses, Months to Forecast, and Revenue Growth % (annual) — do not pull with equal force. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

How the math works

For each month: cash = cash + revenue - expenses. Revenue grows by (annual growth ÷ 12) monthly. Track lowest point and months in deficit. The working is transparent — you can verify every step yourself in the formula section below. No black box, no opaque "proprietary model".

Using this as a check-in

Re-run this every three months. A single reading tells you where you stand; four readings tell you whether things are improving. The trend matters more than any individual snapshot.

What this doesn't capture

The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.

Example Scenario

£20,000 £ + (15,000 £-18,000 £)×12m = -$16,000.00.

Inputs

Starting Cash:20,000 £
Monthly Cash Inflow:15,000 £
Monthly Cash Outflow:18,000 £
Forecast Period:12
Expected Result-$16,000.00

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

Ending cash = starting + (inflow - outflow) × months. Runway = starting / |net monthly| if negative.

Frequently Asked Questions

Cash flow vs profit?
Profit = accounting earnings (revenue minus expenses on the P&L). Cash flow = actual money moving and out. Differences: invoiced revenue vs collected payment, capex spent vs depreciated, inventory bought vs sold. Profitable businesses fail from cash flow problems regularly - check both metrics.
What's runway?
Months until cash runs out at current burn rate. Formula: cash on hand / monthly net burn. Common startup metric: '500k cash, 50k monthly burn = 10 months runway'. Healthy startups maintain 18-24 months runway. Below 6 months is crisis territory - cut costs or raise immediately.
How often to forecast?
Healthy business with 12+ months runway: monthly cash flow forecast sufficient. Tight cash position (3-6 months runway): weekly forecast. Crisis (under 3 months): daily forecast with scenarios. Update forecast against actuals - learn what your model gets wrong and improve.
What if cash flow goes negative?
Three levers: increase inflows (collect debtors faster, raise prices, reduce free trial length), decrease outflows (cut costs, negotiate supplier terms, reduce payroll), or raise capital (debt, equity, line of credit). Start with cost cuts - they're fastest. Capital raises take 3-6 months.

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