How to build a budget that your department heads will actually follow

Most company budgets fail for one of three reasons: they're built top-down with no input from the people spending the money, they're too detailed to be useful, or they're filed in April and forgotten by June. Here's how to build one that works.

Start with a revenue plan, not an expense plan. Your budget is only as credible as your revenue assumptions. Work with your sales and business leadership to build a realistic revenue forecast — conservative, base, and stretch cases. Everything else flows from there.

Build the budget with department heads, not for them. Give each HOD a template with last year's actuals and ask them to justify their requirements for the coming year. They'll be more accountable to a number they helped build.

Keep the structure simple. Group expenses into 4–5 categories per department: people costs, direct costs, overheads, capex, and discretionary. Avoid 40-line budgets that nobody understands.

Build in a variance review. Every month, actual spend vs. budget should be reviewed with HODs. If someone is consistently over budget, find out why — is it a bad budget or bad spending? Both are fixable, but you can't fix what you don't measure.

Reserve 5–10% of your discretionary budget as a contingency. Unexpected opportunities and costs always arise. Having a reserve means you don't have to blow the budget every time.