Start with strategy, not numbers
Before opening a spreadsheet, answer three questions: what are we trying to accomplish this year, what does success look like, and what constraints do we need to work within. Without clear answers, the budget becomes a math exercise disconnected from strategy.
The answers shape everything. A year focused on growth has different spend patterns than a year focused on efficiency. A year preparing for a fundraise has different cash planning than a year running lean to extend runway. The budget should reflect the strategy, not drive it.
Get alignment on strategy before detailed budgeting. A company where sales is planning for aggressive growth while finance is planning for conservative spend will produce an incoherent budget. The top-level strategic alignment makes the bottom-up budget work.
Build revenue bottoms-up
Top-down revenue targets ("we need $15M to justify the valuation") are aspirations. Bottoms-up revenue builds ("current pipeline + new sales capacity × average deal size × close rate = projected revenue") are forecasts. Investors and boards trust the second; they discount the first.
For sales-led businesses: start with existing customer base (renewal assumptions, expansion potential), add new logo acquisition (capacity × productivity × ramp adjustment), apply conversion and timing assumptions. For marketing-led businesses: start with top-of-funnel, apply funnel metrics, convert to revenue.
Stress test the revenue plan. If every AE needs to hit 120% of quota for the plan to work, that is a fragile plan. If the plan works even if AEs hit 85%, that is durable. Build with assumptions that leave room for imperfect execution. Overly tight plans often produce worse outcomes than looser ones because they force bad decisions.
Expenses should be function-driven
Build expenses by function, not by category. Engineering cost = engineer headcount × fully loaded cost per engineer + tooling. Sales cost = AE count × fully loaded cost + commissions + enablement tools. This ties expenses to operational plans so you can see what drives spend.
Headcount is the biggest line item for most growing companies. Plan hires by month, by function, with realistic start dates and ramp assumptions. A hire who starts in Q2 but ramps for 6 months contributes 2 months of productivity in the budget year. The budget should reflect ramp reality, not hire-date optimism.
Non-headcount expenses should be built from specific plans. Marketing spend tied to campaigns. Software costs tied to headcount and tool stack. Professional fees tied to expected projects. When every expense line has a plan behind it, variances become meaningful. Budgets built as "last year + 10%" make variance analysis impossible.
Make the budget useful
Publish it. A budget that lives in finance alone does not change behavior. Each functional leader should see their budget, commit to it, and be held to it. This creates accountability and gives them useful constraints when making decisions during the year.
Review against actual monthly. Variance to plan is the primary management tool. What is tracking ahead, what is tracking behind, what do we need to adjust. Without this cadence, the budget becomes a document reviewed once per year at planning time.
Plan for re-forecasting. Most budgets are wrong in specific ways by the end of Q1. Build in a planned mid-year re-forecast, not as a failure signal but as a normal process. The original budget sets direction; the re-forecast keeps the direction current.