What zero-based budgeting actually means
Zero-based budgeting (ZBB) starts every budget cycle from a base of zero. Instead of taking last year's spend and adding a percentage, each department must justify every line item from scratch. The question shifts from "how much more do we need?" to "why do we need this at all?"
For SaaS companies -- where growth often masks inefficiency -- ZBB can be a powerful tool for maintaining discipline as the business scales.
Why SaaS companies should consider ZBB
SaaS businesses have a particular problem: recurring costs that nobody questions. That third analytics platform someone signed up for in 2023. The contractor who was hired for a project that finished six months ago. The AWS instance running a staging environment nobody uses.
When you build from zero, these costs surface immediately. They have no historical justification to hide behind.
A practical approach: hybrid ZBB
Full zero-based budgeting for every account is impractical for most growing businesses. The administrative overhead would cripple the finance team. Instead, apply ZBB selectively:
Full ZBB for discretionary spend. Marketing programmes, software subscriptions, professional services, travel, and events. These are the categories where legacy spend accumulates.
Driver-based budgeting for headcount. People costs should be planned at the position level with fully loaded costs, not justified from zero each year. Use your workforce plan as the foundation.
Run-rate plus adjustment for infrastructure. Hosting, bandwidth, and core SaaS tools scale with the business. Budget these based on usage drivers, not zero-based justification.
The ZBB process step by step
1. Categorise all spend into decision packages. Group related expenses into logical bundles. For example, "content marketing programme" includes freelance writers, design tools, distribution spend, and analytics.
2. Rank decision packages by business impact. Force department heads to prioritise. If the budget is cut by 20%, which packages get dropped first? This ranking reveals where the real value lies.
3. Set funding levels. For each package, define a minimum viable level and an optimal level. The gap between them is where the negotiation happens.
4. Consolidate and challenge. Finance reviews all submissions, challenges assumptions, and allocates the total budget envelope across ranked packages.
Common pitfalls
The biggest risk with ZBB is fatigue. If the process is too heavy, department heads will game it -- padding estimates to survive the cuts they know are coming. Keep the process lean, focus on material categories, and rotate which departments go through full ZBB each year.
Making it sustainable
ZBB works best as a periodic deep clean, not an annual ordeal. Many organisations run full ZBB every two to three years on a rotating basis, with incremental budgeting in between. This captures the benefits without the burnout.