Your numbers
Projected cash position
Month-by-month forecast
| Month | Income | Outgoings | Tax pot | Net | Balance |
|---|
How the forecast works
1. Opening balance
The cash you actually have today, in your operating account. Exclude the tax pot (it's owed) and the emergency fund (it's locked). Include only what's available for normal business and personal spend.
2. Monthly income
Your realistic average over the year. If you've been freelancing 12+ months, average the last 12. If you're newer, project conservatively based on the contracts you actually have, not what you hope.
3. Monthly outgoings
Business + personal essential spend. Software subscriptions, professional fees, hosting, equipment depreciation, plus rent/mortgage, utilities, food, transport, insurance. Don't separately add tax — the tax-rate field handles that.
4. Tax / NI provision rate
Lenders, accountants and freelancer-finance writers usually advise putting aside 25–30% of every invoice (sole traders below higher-rate) up to 35–40% (above higher-rate or with multiple income streams). The calculator subtracts this from income each month before adding to your balance.
5. Seasonality
Most UK freelance service work has a recognisable seasonal dip. The model applies it to August and December by default — change it in the dropdown if your industry pattern is different (some sectors dip in Jan or hit hardest mid-summer).
The runway
The "runway" figure shows how many months you'd survive if income stopped today, given your current balance and monthly outgoings (excluding tax). It's your operational safety margin.
Worked examples
Monthly contributions to balance: income £5,500 − £4,200 outgoings − £1,375 tax pot = −£75 in a normal month (i.e. you lose a small amount of float monthly).
August and December at 20% dip: income £4,400 → £4,400 − £4,200 − £1,100 = −£900 each.
Over 12 months you accumulate −£75 × 10 + −£900 × 2 = −£2,550. Starting at £8,000, you end at £5,450. Runway at year-end ≈ 1.3 months.
This is the practical "I'm one bad month from a problem" scenario. The intervention isn't more income — it's lowering essential outgoings, raising the tax-pot accuracy, or building a buffer before the dip months hit.
Monthly contribution: £8,000 − £4,200 essential outgoings − £2,400 tax pot = +£1,400/month float.
Starting balance £8,000, no dips: 12 months later, balance £24,800. Runway ~6 months.
This is the healthier picture. The contractor's float grows steadily; the emergency fund and tax pot are both being built. The risk now is overspending the float during good months rather than holding it for a quiet quarter.
No — it's a planning input based on the average inputs you provide and a simple seasonality pattern. Actual cash flow will be more variable. The forecast is most useful as a "would I survive this scenario?" check, not as a precise prediction.
Because if you don't, you'll spend it. The 25–35% tax-pot habit is the single most important freelance cashflow practice. Setting aside monthly means you reach 31 January with the tax already provisioned, not needing to find it. See our cashflow management guide.
25% is a baseline for sole traders below the higher-rate threshold (£50,270 of taxable income in 2025/26). 30–35% above higher-rate. Ltd directors taking salary + dividends typically use 25–30% of total drawings. The exact figure varies — run your numbers through the tax calculator for your specific structure.
The simple monthly-average model in this calculator smooths over that. For lumpy income, forecast conservatively — average across 12 months including the gaps — and rely on your operating buffer to cover the lows. The volatility itself is best handled by a budgeting app that tracks actuals daily (Emma and similar). See the emergency fund calculator for the buffer side.
If you're VAT-registered (above £90k turnover), 20% of your invoice value is owed to HMRC separately. The cashflow calculator doesn't separately model VAT — the simplest approach is to set your "monthly income" to the net (pre-VAT) figure and treat VAT as a pass-through (received in, paid out in next quarter). See our VAT return calculator.
How many months you could survive at current outgoings if income stopped today. Calculated as closing balance ÷ monthly outgoings. 3+ months of runway is a comfortable position; under 1 month is fragile. Building the runway is the goal of the emergency fund.
Yes — but use the company's pre-tax profit as "monthly income" rather than your personal drawings. The tax-pot rate then represents combined corporation tax + dividend tax + employee NI. The mechanics are the same; the line items differ.
Monthly during your monthly close routine. A 30-minute monthly check catches forecast drift before it becomes a cashflow surprise. Adjust your average-income input if reality has shifted materially over 3+ months.
Estimating tool only. Not regulated financial advice. The forecast assumes constant averages with simple seasonality — actual cash flow is more variable. Use the output as a planning input, not a guarantee.