Free 13-Week Cash Flow Calculator
See when cash may get tight before bills come due. Enter your starting bank balance and the money you expect to collect and pay each week. This rolling forecast calculates your ending cash and flags weeks below your chosen reserve.
No signup required. Amounts stay in this page while it is open; they are not saved. Export a CSV before closing or refreshing. All amounts use USD.
First reserve warning: week 1. Review the weeks highlighted in amber.
On small screens, scroll the table horizontally. Enter positive totals for cash in and cash out. Include borrowing in cash in and repayments in cash out; keep their detail in your supporting records.
| Week | Opening cash | Cash in ($) | Cash out ($) | Net movement | Ending cash | Reserve shortfall |
|---|---|---|---|---|---|---|
| Week 1 | $18,000.00 | -$6,000.00 | $12,000.00 | $3,000.00 | ||
| Week 2 | $12,000.00 | $2,000.00 | $14,000.00 | $1,000.00 | ||
| Week 3 | $14,000.00 | $2,000.00 | $16,000.00 | $0.00 | ||
| Week 4 | $16,000.00 | $2,000.00 | $18,000.00 | $0.00 | ||
| Week 5 | $18,000.00 | -$10,000.00 | $8,000.00 | $7,000.00 | ||
| Week 6 | $8,000.00 | $2,000.00 | $10,000.00 | $5,000.00 | ||
| Week 7 | $10,000.00 | $2,000.00 | $12,000.00 | $3,000.00 | ||
| Week 8 | $12,000.00 | $2,000.00 | $14,000.00 | $1,000.00 | ||
| Week 9 | $14,000.00 | $2,000.00 | $16,000.00 | $0.00 | ||
| Week 10 | $16,000.00 | $2,000.00 | $18,000.00 | $0.00 | ||
| Week 11 | $18,000.00 | $2,000.00 | $20,000.00 | $0.00 | ||
| Week 12 | $20,000.00 | $2,000.00 | $22,000.00 | $0.00 | ||
| Week 13 | $22,000.00 | $2,000.00 | $24,000.00 | $0.00 |
How to use the cash-flow calculator
- Start with available cash. Use your reconciled balance, excluding restricted funds or an unused credit limit.
- Schedule collections. Use expected customer payment dates, cash sales and other receipts. An invoice is not cash until it is collected.
- Schedule payments. Include payroll, suppliers, rent, taxes, debt payments, equipment and owner distributions on their payment dates. Do not enter noncash depreciation.
- Choose a reserve. This is a planning threshold, not a universal rule. Use an amount that reflects your essential commitments and uncertainty.
- Update every week. Replace the completed week with actual results and roll your plan forward in your exported file. Compare a base case with slower collections or higher costs.
Understand the results
Ending cash = opening cash + cash in − cash out. Each ending balance becomes the next week's opening balance. Reserve shortfall equals the reserve minus ending cash, with a minimum of zero. A reserve warning means the forecast is below your chosen cushion; a negative balance signals an unfunded cash gap.
The example starts with $18,000, collects $45,000 and pays $51,000 in week 1. Ending cash is $12,000, so a $15,000 reserve has a $3,000 shortfall. These are fictional numbers for learning.
What this forecast cannot tell you
Weekly totals can hide a midweek shortage. Check daily timing when cash is close to zero. This tool does not calculate profit, taxes, interest or a funding approval. A positive balance can depend on uncertain receipts; review assumptions before committing spending.
Frequently asked questions
Why forecast 13 weeks?
Thirteen weeks covers about one quarter while keeping the focus on near-term collections and payment dates. A longer monthly plan helps with strategy; weekly detail helps with immediate liquidity decisions.
Should I include sales or customer collections?
Include cash you expect to receive in that week. Credit sales belong in the collection week, which may be later than the sale.
Does a negative result mean my business is unprofitable?
No. It means the scheduled payments exceed available cash in this forecast. Profit and cash differ because of collection timing, inventory, borrowing, investment and other transactions.
Keep learning
How to Build a 13-Week Cash Flow Forecast · Why Your Business Is Profitable but Has No Cash
Cash-flow management guide · Profit vs. cash flow · Working capital · Cash conversion cycle
Educational planning tool. Use accurate records and review significant financing or tax decisions with a qualified adviser.