Cashflow Buffer Calculator

Keeping track of your cashflow buffer helps you understand how long your business can operate safely with the money you currently have.

This calculator gives you a simple, instant view of your financial breathing space — in months, weeks, and your danger‑zone threshold — so you can make confident decisions before things get tight.

1. How this calculator works

This calculator shows how long your business can keep going with the cash you currently have.

It compares your available cash against your average monthly costs to give you a clear “survival window” — in both months and weeks.

You’ll also see your danger zone threshold (the minimum cash you need to cover one month of costs) and how long it will take before you reach it.

2. Enter your numbers into the calculator below:

Add your current cash and your average monthly costs.


Your results will appear automatically — no formulas, no spreadsheets, no guesswork.


This tool is designed to give you instant clarity on how long your cash will last and when you may need to take action.

3. Worked Example

Imagine your business currently has £12,000 in available cash, and your average monthly costs are £4,000.

  • Cashflow Buffer (Months) £12,000 ÷ £4,000 = 3 months of cash remaining
  • Cashflow Buffer (Weeks) 3 × 4.33 = 13 weeks of cash remaining
  • Danger Zone Threshold (£) Your danger zone is £4,000 — the minimum cash you need to cover one month of costs
  • Months Until Danger Zone (£12,000 − £4,000) ÷ £4,000 = 2 months until you reach the danger zone

This means you have around three months of financial breathing space, and you’ll reach the danger zone in about two months if nothing changes.

4. Why this matters

Your cashflow buffer is one of the simplest and most powerful indicators of financial health. It shows how long your business can operate safely with the cash you currently have, highlights when you may need to reduce costs or increase income, and gives you early warning before cash becomes tight.

Understanding your buffer helps you make confident decisions, plan ahead, and avoid surprises — especially during quieter periods or when costs increase unexpectedly.

Cashflow Buffer Calculator

This is the total cash your business has access to — including your bank balance, savings, reserves, PayPal/Stripe balances, and any other cash you can use to pay business costs. Don’t include personal money.
This field is required.
This includes everything your business pays out each month — cost of sales, materials, overheads, wages, rent, subscriptions, fuel, insurance, loan repayments, and any other regular expenses.
This field is required.
This shows how many months your business can keep going with the cash you currently have, based on your monthly outgoings. It’s your real survival window — how long your money will last before you run out.
This shows how many weeks your business can keep going with the cash you currently have. It’s simply your survival window expressed in weeks instead of months — helpful if you want a more detailed, week‑by‑week view of how long your money will last.
This is the minimum cash your business needs to cover one month of costs — your survival line. If your cash drops below this amount, you’re officially in the danger zone and need to take action quickly.
This shows how long it will take before your cash drops below one month of costs — your “danger zone”. It helps you see how quickly your buffer is shrinking and gives you early warning to take action before things get tight.
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