Plan the cash coming in and going out over the next 13 weeks or 12 months. Start from your opening balance, add receipts and payments line by line, and the forecast shows every ending balance and warns you before cash dips below your safety buffer.
Last updated:
Forecast period
Ending balance–
Lowest balance–
Total inflows–
Total outflows–
Ending balanceBelow bufferNegativeBuffer level
Type amounts straight into the grid. The ⇉ button copies a line's first amount to every period; ÷4 on the 13-week view repeats it every 4 weeks (monthly bills).
Your forecast is saved in this browser only. Nothing is uploaded.
Advertisement
Advertisement
How to use the Cash Flow Forecast Calculator
Pick 13 weeks or 12 months and set the start date of the first period.
Enter your opening cash balance (what is in the bank today) and the minimum cash buffer you never want to go below.
Fill the inflow lines with the cash you expect to collect each period: customer payments, loans received, refunds.
Fill the outflow lines: payroll, rent, suppliers, loan payments, taxes. Use ⇉ to repeat an amount across all periods or ÷4 for monthly bills on the weekly view.
Read the warning and the chart to find your lowest balance, then download the CSV or print the forecast.
The ending balance becomes the next period's opening balance. The forecast's lowest point is the smallest ending balance across all periods. It shows the most cash you will need on hand, and the week or month when you need it.
Week
Opening
Inflows
Outflows
Net
Ending
1
$20,000
$12,000
$24,000
−$12,000
$8,000
2
$8,000
$9,500
$7,450
+$2,050
$10,050
3
$10,050
$14,000
$18,500
−$4,500
$5,550
In this short example, payroll and rent land in week 1 and cash drops by $12,000 even though the business collects money every week. That timing effect is what a forecast is meant to catch.
Each payroll run, rent date and large invoice by week
Monthly totals per line
Update
Weekly: replace the finished week with actual figures and add a new week 13
Monthly, with a quarterly review
Watch out for
Months with 5 weeks of payroll; quarterly tax dates
Gaps inside a month (big payment on the 1st, receipts at month-end)
Tips for an accurate forecast
Use payment dates, not invoice dates. Look at how many days your customers really take to pay and shift receipts accordingly.
List lumpy payments separately. Quarterly estimated taxes, annual insurance, equipment purchases and loan balloon payments cause most surprises.
Be conservative. Forecast receipts slightly late and payments slightly early. A forecast that turns out better than expected is easier to live with.
Compare with actuals. Each week or month, compare the forecast with your bank statement. That shows you which lines you tend to misjudge.
Include owner drawings and loan proceeds. They don't show on a profit and loss statement, but they move cash.
Frequently asked questions
What is a 13-week cash flow forecast?
It is a week-by-week projection of cash receipts and payments covering one quarter (13 weeks). Each week starts with the previous week's ending balance, adds expected inflows and subtracts expected outflows. Lenders, turnaround advisers and finance teams use it because weekly detail shows short-term cash gaps that a monthly budget can hide.
How is the ending balance calculated?
Ending balance = opening balance + total cash inflows − total cash outflows for the period. The ending balance of one period becomes the opening balance of the next, so a single large payment carries forward into every later period.
What is the difference between a cash flow forecast and a profit and loss statement?
A profit and loss statement records revenue when it is earned and expenses when they are incurred. A cash flow forecast only counts money when it actually arrives in or leaves the bank. A profitable business can still run out of cash if customers pay slowly or if large bills, loan repayments or tax payments fall in the same week.
What should I set as my minimum cash buffer?
There is no single rule. Many small businesses aim to keep enough cash for several weeks of fixed costs such as payroll and rent, so they can absorb a late customer payment. Enter the amount you are comfortable with; the tool flags every period where the forecast falls below it.
Should I enter sales or cash received?
Enter cash received. If you invoice customers on 30-day terms, a sale made in week 1 usually appears as an inflow around week 5. The same applies to bills you pay on credit: record them in the period you will actually pay them.
What can I do if the forecast shows a shortfall?
Common options are to chase overdue invoices or offer an early-payment discount, delay non-essential purchases, negotiate later payment dates with suppliers, spread large payments over several periods, or arrange a credit line before the gap arrives. Move the amounts in the grid to test each option.
Is my data private?
Yes. The forecast runs entirely in your browser and is saved only in this browser's local storage. Nothing is uploaded. Download the CSV if you want a backup or want to share it.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.