Budgeting for Business

The startup that burned $2 million on vibes

In 2018, a venture-backed SaaS startup in San Francisco raised a $3 million seed round. The two founders were brilliant engineers. They built an amazing product. They hired fast — a designer, three developers, a marketing lead, a sales rep, an office manager. They rented a trendy co-working space. They sponsored a conference. They bought standing desks for everyone.

Eighteen months later, they were out of money. Not because the product failed — they had paying customers and growing revenue. But they never built a budget. They never mapped out how much they could spend per month and how long their funding would last. They operated on vibes: "We have millions in the bank, we will be fine."

They were not fine. The $3 million was gone, revenue was only $30,000/month, and they could not raise a Series A because investors asked for a financial plan and got a blank stare. The company shut down.

A budget would have shown them, on day one, that their burn rate of $165,000/month gave them 18 months of runway — and that they needed to hit $100,000/month in revenue by month 12 to have any chance of survival. They could have planned for that. Instead, they planned for nothing.

What is a budget?

A budget is a financial plan for a specific period — usually a month, quarter, or year. It estimates how much money will come in (revenue) and how much will go out (expenses), and it sets targets for both.

A budget answers four questions:

1. How much revenue do we expect? Based on past performance, pipeline, seasonality, and growth plans.
2. How much will we spend? Broken down by category: payroll, rent, marketing, supplies, etc.
3. What is the expected profit or loss? Revenue minus expenses.
4. How does this align with our goals? Are we investing in growth? Cutting costs? Building cash reserves?

Building a budget: step by step

Here is a simplified annual budget for a small e-commerce business:

Variance analysis: budget vs. reality

A budget is only useful if you compare it to what actually happened. Variance analysis is the process of looking at where reality differed from the plan — and understanding why.

Favourable variance: Actual is better than budget (more revenue than expected or less expense than expected). Unfavourable variance: Actual is worse than budget (less revenue or more expense than expected).

The real value is not in the numbers — it is in the why. Revenue was $8,000 below budget. Why? Did a client delay? Did a campaign underperform? Did you lose a recurring customer? Marketing was $2,500 over budget. Why? An unplanned campaign? A tool that cost more than expected?

There Are No Dumb Questions

"How often should I review the budget vs. actuals?"

Monthly, at minimum. Many businesses review weekly for cash-sensitive items (like payroll and receivables) and monthly for the full budget. The review should take 30-60 minutes and result in specific actions: adjust the forecast, cut spending, accelerate a campaign, or renegotiate a contract.

"What if the budget is wrong from the start?"

Then fix it. A budget is a living document, not a stone tablet. If you set revenue at $50K/month but consistently hit $35K, update the budget. Operating against a fantasy budget is worse than having no budget at all because it gives you false confidence.

Types of budgets

Operating budget

The main budget covering day-to-day revenue and expenses. This is what most people mean when they say "the budget." It answers: will we be profitable this period?

Capital budget

Plans for large, long-term investments: new equipment, office buildout, technology infrastructure. These items do not appear as immediate expenses — they are capitalized on the balance sheet and depreciated over time.

Cash budget

A detailed plan for cash inflows and outflows. Different from the operating budget because it accounts for timing — when cash actually moves, not when revenue is earned or expenses are incurred. This is essentially the cash flow forecast from the previous module, formalized as a budget.

Zero-based budgeting

Traditional budgeting starts with last year's numbers and adjusts: "We spent $4,000 on marketing last year, so let us budget $4,500 this year." This is called incremental budgeting, and it has a problem: it assumes last year's spending was correct. It rarely is.

Zero-based budgeting (ZBB) starts from zero every period. Every expense must be justified from scratch. You do not get $4,000 for marketing because you spent $4,000 last year. You get marketing budget only if you can explain what the money will do, what the expected return is, and why it deserves funding over other priorities.

ZBB is more work, but it forces the kind of honest examination that leads to better decisions. Many companies use a hybrid: incremental for most categories, zero-based for discretionary spending (marketing, R&D, travel).

Forecasting revenue

Revenue forecasting is the hardest part of budgeting — and the most important. Here are three common methods:

1. Historical growth rate

Take last year's revenue, apply a growth rate. Simple, but assumes the future looks like the past.

Example: Last year: $400,000. Expected growth: 15%. Forecast: $460,000.

2. Bottom-up forecasting

Build the forecast from individual revenue drivers: number of customers, average deal size, conversion rates, repeat purchase rates.

Example: 200 customers x $2,000 average deal x 1.5 purchases/year = $600,000.

3. Pipeline-based forecasting (B2B)

For businesses with a sales pipeline, weight each deal by its probability of closing.

Example: 10 deals worth $50,000 each at 30% probability = $150,000 weighted forecast.

There Are No Dumb Questions

"What is burn rate and runway?"

Burn rate is how much cash a company spends per month (net of any revenue). If you spend $50,000/month and earn $20,000/month, your net burn rate is $30,000/month. Runway is how many months of cash you have left: cash in bank divided by net burn rate. If you have $180,000 and burn $30,000/month, your runway is 6 months. Every startup founder should know their runway at all times.

Key takeaways

• A budget is a financial plan, not a restriction. It tells you where your money goes and whether your plan works on paper before you execute it.
• Start with conservative revenue and thorough expenses. List fixed costs, variable costs, and discretionary spending separately.
• Variance analysis is where the value is. Compare budget to actual monthly, find the differences, and understand why they happened.
• Zero-based budgeting forces honest evaluation by requiring every expense to be justified from scratch, rather than rolling forward last year's spending.
• Forecast revenue using multiple methods — historical growth, bottom-up drivers, and pipeline weighting — then take the most conservative estimate.
• Track burn rate and runway if you are a startup or any business spending more than it earns. Know exactly how many months of cash you have.