A cash flow forecast is not a spreadsheet exercise. It is how you know whether you can make payroll in six months. Whether you can afford your next hire. Whether you need to start fundraising now or in three months.

82% of small businesses fail due to cash flow problems (U.S. Bank data). A 12-month rolling forecast is the simplest way to see problems before they hit.

Below is a complete 12-month cash flow forecast for a seed-stage SaaS startup. The numbers are realistic, the formulas are transparent, and you can adapt the entire thing to your business. If you want to run the numbers yourself, use our cash flow forecast calculator to model different scenarios instantly.

The Scenario: Seed-Stage SaaS Startup

Here is the business we are forecasting:

Funding: $2M seed round closed, $1.8M in the bank after legal fees and initial expenses
Team: 3 employees (2 engineers, 1 founder/CEO) at close, growing to 7 by month 12
Monthly burn: Starting at $80K/mo, growing to $173K/mo as the team scales
Revenue: $15K MRR, growing at a conservative 10% month-over-month
Goal: Hit Series A metrics (roughly $50K+ MRR, strong retention) within 12 months

This is a real-world profile. The company has product-market fit signals but is pre-scale. The forecast will reveal whether the runway holds long enough to reach the next milestone -- and our seed-stage runway benchmarks suggest most companies in this position have 14-18 months of cash.

The 12-Month Forecast

Every number below feeds forward. Starting cash in month 2 equals ending cash in month 1. Revenue compounds at 10% monthly. Expenses step up as hires land. Follow the ending cash balance row -- that is where the story lives.

Months 1-6

Line Item	M1	M2	M3	M4	M5	M6
Starting Cash	$1,800,000	$1,735,000	$1,669,500	$1,603,650	$1,525,915	$1,447,177
Revenue (MRR)	$15,000	$16,500	$18,150	$19,965	$21,962	$24,158
Total Cash In	$15,000	$16,500	$18,150	$19,965	$21,962	$24,158
Payroll & Benefits	$52,000	$52,000	$52,000	$65,000	$65,000	$65,000
Software & Tools	$4,500	$4,500	$4,500	$5,200	$5,200	$5,200
Office / Infrastructure	$3,500	$3,500	$3,500	$3,500	$3,500	$3,500
Marketing & Ads	$8,000	$10,000	$12,000	$12,000	$15,000	$15,000
Other Operating	$12,000	$12,000	$12,000	$12,000	$12,000	$12,000
Total Cash Out	$80,000	$82,000	$84,000	$97,700	$100,700	$100,700
Net Cash Flow	-$65,000	-$65,500	-$65,850	-$77,735	-$78,738	-$76,542
Ending Cash	$1,735,000	$1,669,500	$1,603,650	$1,525,915	$1,447,177	$1,370,635

Key events: Hire #4 (engineer) lands in month 4, bumping payroll from $52K to $65K. Marketing spend increases as early paid channels show positive ROI signals.

Months 7-12

Line Item	M7	M8	M9	M10	M11	M12
Starting Cash	$1,370,635	$1,275,208	$1,176,439	$1,059,718	$942,255	$809,585
Revenue (MRR)	$26,573	$29,231	$32,154	$35,369	$38,906	$42,797
Total Cash In	$26,573	$29,231	$32,154	$35,369	$38,906	$42,797
Payroll & Benefits	$80,000	$80,000	$95,000	$95,000	$110,000	$110,000
Software & Tools	$6,000	$6,000	$7,000	$7,000	$7,500	$7,500
Office / Infrastructure	$5,000	$5,000	$5,000	$5,000	$5,000	$5,000
Marketing & Ads	$18,000	$22,000	$25,000	$28,000	$30,000	$32,000
Other Operating	$13,000	$15,000	$16,875	$17,832	$19,076	$18,067
Total Cash Out	$122,000	$128,000	$148,875	$152,832	$171,576	$172,567
Net Cash Flow	-$95,427	-$98,769	-$116,721	-$117,463	-$132,670	-$129,770
Ending Cash	$1,275,208	$1,176,439	$1,059,718	$942,255	$809,585	$679,815

Key events: Hire #5 (marketer) in month 7, hire #6 (engineer) in month 9, hire #7 (customer success) in month 11. Marketing spend accelerates as the company pushes toward Series A metrics.

The Bottom Line

Starting cash: $1,800,000. Ending cash after 12 months: $679,815. That is roughly 5 months of remaining runway at month-12 burn rates. The company spent $1.44M in total expenses over the year and generated $321K in cumulative revenue.

This is the critical insight a forecast reveals. Without one, the founder might assume 18+ months of runway. The forecast shows it is closer to 17-18 months total -- meaning fundraising conversations need to start by month 9-10 at the latest, because Series A rounds take 3-6 months to close. You can verify your own runway with our burn rate calculator.

Line-by-Line Breakdown

Revenue

MRR grows at 10% month-over-month, compounding from $15K to $42.8K. The formula is simple: Previous Month MRR x 1.10.

Why 10% and not the 15% you might be hoping for? Forecast the revenue you can defend, not the revenue you dream about. If your last three months averaged 10% growth, use 10%. Create a separate upside scenario at 15% -- but your base forecast should be conservative. For deeper context on structuring your revenue projections, see our cash flow forecasting guide for small businesses.

Payroll and Benefits

This is your largest expense line and it moves in steps, not curves. Each new hire creates a jump. The numbers above use a 1.3x multiplier on base salary to account for benefits, payroll taxes, and equipment.

Plan hire dates in advance and mark them in the forecast. A $120K/year engineer costs roughly $13,000/month fully loaded. That single hire changes your monthly burn by 10-15%.

Software and Tools

Starts at $4,500/month and grows to $7,500 as the team scales. Per-seat SaaS tools (Slack, GitHub, Figma, monitoring) add up faster than most founders expect. Budget $800-$1,200 per employee per month for tooling.

Marketing

The most variable line item. In this forecast, marketing spend nearly quadruples from $8K to $32K as the company finds channels that work and increases investment. Marketing spend should be tied to measurable outcomes, not arbitrary percentages. If a channel returns 3x+ in pipeline, increase spend. If it does not, cut it.

Other Operating Expenses

Legal, accounting, insurance, travel, miscellaneous. Budget $3,000-$4,000 per employee per month as a baseline for everything outside the categories above. This catches the long tail of expenses that individually seem small but collectively matter.

3 Mistakes That Kill Forecast Accuracy

1. Forecasting Revenue You Hope For, Not Revenue You Can Defend

The single biggest source of forecast error. Founders project 20% monthly growth because one good month hit that number. Your base case forecast should use your trailing 3-month average growth rate. Create an optimistic scenario separately -- do not blend hope into your operating plan. Understanding what a healthy seed-stage P&L structure looks like will help you set realistic targets.

2. Ignoring Seasonality

Even B2B SaaS has seasonal patterns. Q4 budget cycles can accelerate enterprise deals. Summer months (June-August) often see slower SMB signups. December is nearly a dead month for outbound sales. If you have 6+ months of data, look for patterns. If you do not, add a 10-15% downward adjustment to months where you expect slowdowns.

3. Treating the Forecast as Static

A forecast written in January and never updated is fiction by March. Update your forecast monthly with actual numbers. Replace projected revenue with real revenue. Replace estimated expenses with actual expenses. Then re-forecast the remaining months. This rolling approach means your forecast is always grounded in reality, not in the assumptions you made months ago.

How to Use This Forecast

A forecast sitting in a spreadsheet does nothing. Here is how to make it operational:

Decide when to start fundraising. The standard advice is to begin when you have 9-12 months of runway remaining. In the example above, that threshold hits around month 8-9. If you wait until month 12, you are fundraising from a position of desperation -- investors can smell that.

Determine when you can afford the next hire. Each hire in the forecast above was timed based on runway impact. Adding hire #6 in month 9 instead of month 7 preserved two extra months of runway. Every hire decision is a runway decision.

Identify cash-tight months early. If your forecast shows a month where net cash flow worsens sharply (like month 9 above, where the net burn jumps by $18K), you have time to adjust. Delay a hire by one month. Cut an underperforming marketing channel. Negotiate better payment terms with vendors. The forecast gives you lead time to make these decisions calmly rather than in crisis.

Communicate with your board and investors. Sharing a 12-month forecast with your board is not optional -- it is expected. The forecast above, updated monthly with actuals, tells a clear story about trajectory, burn efficiency, and runway. Investors who see a founder managing cash thoughtfully are far more likely to fund the next round.

Build Your Own Forecast

The example above is a starting template, not a prescription. Your numbers will be different. Your growth rate, team size, and expense structure are unique to your business.

Start with your actual bank balance, your real MRR, and your current monthly expenses. Project forward 12 months using conservative assumptions. Then stress-test it: what happens if growth drops to 5%? What if a key hire takes two months longer than planned?

Use our cash flow forecast calculator to model these scenarios in minutes instead of hours. Plug in your numbers, adjust the variables, and see exactly when your runway runs out -- no spreadsheet required.

The companies that survive are not the ones with the most cash. They are the ones that know exactly how much cash they have, how fast it is going, and what they are going to do about it.

12-Month Cash Flow Forecast (Free Example)