Most organisations budget the same way they always have: take last year’s figures, adjust for inflation and known changes, and approve the result. This approach is fast, familiar, and deeply flawed. It perpetuates historical spending patterns regardless of whether those patterns still make sense. It rewards departments that spent their full allocation last year. It rarely surfaces the question of whether any given cost is actually producing value commensurate with its budget line.
Zero-based budgeting offers a fundamentally different discipline: every cost must be justified from zero at the start of each budget cycle, as though the organisation were being built from scratch. No cost is approved simply because it was approved before. The result, when executed well, is a budget that reflects what the organisation actually needs rather than what it has always spent.
This article provides a clear, practical comparison of both approaches, examining how each works, where each produces the best outcomes, the significant implementation challenges of zero-based budgeting, and how forward-thinking finance leaders are combining elements of both.
Key Takeaways
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10-25% Cost reduction typically achieved in the first full ZBB cycle, according to McKinsey research on organisations implementing zero-based budgeting rigorously for the first time |
3-4x Longer to complete than traditional budgeting: the time cost of ZBB is its most significant practical barrier, particularly in large organisations |
Neither Is universally superior. The most effective approach depends on the organisation’s strategic moment, cost structure, and management capability |
Hybrid ZBB applied selectively to high-cost, discretionary areas while using incremental budgeting for stable operational costs: the approach most leading organisations now use |
- Traditional (incremental) budgeting takes the prior year’s budget as its starting point and adjusts upward or downward. It is fast and simple but systematically perpetuates historical inefficiencies.
- Zero-based budgeting requires each budget holder to justify every cost from scratch each cycle, linking all spending to specific activities and the value those activities produce.
- ZBB is most effective as a periodic strategic reset tool rather than an annual discipline for every cost line. Running full ZBB every year on the entire cost base is neither practical nor necessary for most organisations.
- The cultural and behavioural change required to implement ZBB effectively is as significant as the analytical work. Finance leaders who treat ZBB as a spreadsheet exercise rather than a management behaviour change programme consistently underdeliver its benefits.
- Both approaches carry risks: incremental budgeting risks funding irrelevant activities; ZBB risks destroying productive long-term investments by treating every cost as equally discretionary.
Traditional (Incremental) Budgeting: How It Works and Why It Dominates
Traditional budgeting, also known as incremental budgeting, is the dominant budgeting method in most organisations globally. Its logic is straightforward: the previous year’s approved budget is used as the baseline, and adjustments are made for known cost changes (salary increases, inflation, new headcount, new projects) to produce the coming year’s budget.
Its dominance is not accidental. For organisations with relatively stable cost bases, predictable activity levels, and limited management bandwidth for detailed budget analysis, incremental budgeting is genuinely efficient. It takes weeks rather than months. It requires minimal training. It produces a defensible budget that builds on demonstrated spending history. And it creates continuity: teams know broadly what to expect and can plan accordingly.
The Mechanics of Incremental Budgeting
| Stage | What Happens | Typical Outcome |
|---|---|---|
| Baseline setting | Prior year’s budget (or actual spend) is distributed to budget holders as their starting point for next year’s submission | Historical spending becomes the de facto legitimised baseline, regardless of whether all activities remain relevant |
| Adjustment submissions | Budget holders submit requests for increases above baseline, justifying each increment. Decreases below baseline are rarely volunteered. | Bias towards upward adjustment; departments have strong incentive to protect their baseline and argue for increments |
| Negotiation and approval | Finance and senior leadership review increment requests, apply blanket percentage adjustments, and negotiate with budget holders | Cuts tend to be applied uniformly rather than strategically, penalising efficient departments alongside inefficient ones |
| Final approval | Consolidated budget is approved, typically reflecting a modest percentage increase or decrease on the prior year | Budget reflects negotiation outcomes and historical patterns more than current strategic priorities |
The Structural Problems with Incremental Budgeting
The most significant problem with traditional budgeting is what it never asks. It never asks whether an existing activity is worth continuing at all. It never asks whether the money spent on a particular function last year produced commensurate value. It never asks whether the organisation’s cost structure is aligned with its current strategy or its strategy from five years ago.
The result is what finance professionals call “budget inertia”: spending that persists because it has always existed, not because it continues to create value. A 2020 study by Deloitte found that organisations using purely incremental budgeting allocate on average 90% of next year’s budget to activities that were also funded the year before, with genuinely new strategic priorities competing for the remaining 10%. This structural conservatism makes incremental budgeting a particularly poor fit for organisations undergoing transformation, entering new markets, or facing significant competitive pressure to reduce their cost base.
Zero-Based Budgeting: Origins, Philosophy, and Mechanics
Zero-based budgeting was developed by Peter Pyhrr at Texas Instruments in the early 1970s and was later adopted by President Jimmy Carter for the US federal government in 1977, though that implementation ultimately proved too administratively burdensome to sustain at federal scale. The corporate world has revisited and refined the approach significantly since then, with companies including Unilever, AB InBev, and 3G Capital’s portfolio companies becoming widely cited ZBB practitioners.
The core principle is that every budget starts at zero. No cost is assumed. Every activity must be identified, its purpose stated, its cost calculated, and its value justified to the organisation. Budget holders are not defending adjustments to a baseline. They are building their budget from scratch, with each cost line requiring explicit justification.
The ZBB Process in Practice
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Phase 1 Identify decision units The organisation is broken into “decision units”: discrete activities, functions, or cost centres that can be individually evaluated. Each decision unit is owned by a manager who is accountable for building and defending its budget. |
Phase 2 Build decision packages Each decision unit owner prepares one or more “decision packages”: documents that describe the activity, its purpose, its cost at different funding levels (minimum, current, enhanced), and the consequences of funding it at each level or not funding it at all. |
Phase 3 Rank decision packages Senior managers rank all decision packages in order of strategic priority. This is the most intellectually and politically demanding step: it forces explicit trade-offs between activities rather than allowing all costs to be funded by default. |
Phase 4 Allocate resources Resources are allocated down the ranked list of decision packages until the available budget is exhausted. Activities below the funding line are not funded regardless of historical precedent. This is where ZBB’s value and its political difficulty become most visible. |
The Corporate Finance Institute, one of the most widely used resources for finance professionals, provides detailed guidance on ZBB implementation mechanics and the decision package construction process at corporatefinanceinstitute.com, which is worth reviewing alongside this article for a more technical treatment of the methodology.
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Direct Comparison: Eight Dimensions That Matter
| Dimension | Traditional (Incremental) | Zero-Based Budgeting |
|---|---|---|
| Starting point | Prior year’s budget or actual spend | Zero: every cost must be newly justified |
| Time to complete | Relatively quick: weeks for most organisations | Significantly longer: months for a thorough first implementation |
| Cost visibility | Low: costs are adjusted in aggregate without examining each activity’s purpose or value | High: every cost is examined, named, and linked to a specific activity and outcome |
| Strategic alignment | Weak: historical allocation patterns persist even when strategy has changed | Strong: resources are explicitly allocated to current strategic priorities |
| Cost reduction potential | Limited: cuts are typically applied as a blanket percentage and rarely challenge the existence of cost categories | High: surfaces zombie costs that would never be identified through incremental review |
| Management burden | Low: familiar process requiring limited management time | High: requires significant management time to build and review decision packages |
| Innovation and growth | May fund new strategic investments but competes with entrenched legacy spending for limited marginal budget | Liberates resources by defunding low-value legacy activities, but risk of under-investing in long-term capability development |
| Cultural impact | Reinforces departmental ownership of historical budget territories; can entrench silo behaviour | Forces transparency and cross-functional trade-off discussion; can create short-termism if applied too rigidly |
Where ZBB Has Worked and Where It Has Struggled
The evidence on ZBB outcomes is instructive and more nuanced than advocates on either side typically acknowledge. The methodology has produced remarkable results in specific contexts and disappointing ones in others, and the difference is rarely about the method itself.
Where ZBB has delivered
3G Capital’s implementation of ZBB across its portfolio companies (including Kraft Heinz, AB InBev, and Burger King) became the most widely studied corporate ZBB case study of the 2010s. The approach generated significant margin expansion at multiple companies in the short term, with cost reductions of 15-25% in the first cycle widely reported in financial press coverage and equity research at the time.
Unilever’s adoption of a ZBB-inspired approach to overhead and discretionary spending from 2016 onwards is documented in their annual reports and investor presentations, showing sustained improvement in underlying operating margin while the company simultaneously increased investment in brand and innovation. The key in Unilever’s case was applying ZBB selectively to overhead and discretionary costs rather than to the entire cost base.
Where ZBB has underdelivered
The most common ZBB failure pattern is what has been termed “zero-based theatre”: organisations that adopt the language and process of ZBB without the cultural and management commitment that makes it work. Decision packages are prepared as a compliance exercise rather than a genuine cost challenge. Ranking discussions are politically managed to protect existing budgets. And the outcome closely resembles what incremental budgeting would have produced, at three times the cost in management time.
A second failure mode is applying ZBB so comprehensively that it discourages long-term investment. Kraft Heinz’s struggles from 2018 onwards, which included significant goodwill impairments and brand underinvestment, were attributed in part to ZBB being applied too aggressively to brand-building and R&D budgets that produce returns over multi-year horizons rather than within a single budget cycle.
The Case for a Hybrid Approach
The most practically effective approach for most organisations is neither pure incremental budgeting nor comprehensive annual ZBB. It is a hybrid that applies the right level of scrutiny to the right parts of the cost base at the right time.
| Cost Category | Recommended Approach | Rationale |
|---|---|---|
| Core operational costs (people, facilities, compliance) | Incremental with periodic deep-dive review every three to five years | Highly stable costs with limited discretionary variability; full ZBB annually adds management time without proportionate benefit |
| Overhead and support functions (HR, IT, finance, marketing) | ZBB or modified ZBB applied on a rolling basis, covering different functions in different years | These costs are most prone to budget inertia and have the highest potential for value-for-money improvement through challenge |
| Discretionary and project spend | Full ZBB annually: every discretionary cost must be justified from zero | Discretionary costs are most subject to historical bias and most amenable to genuine challenge; this is where ZBB delivers its clearest value |
| Strategic investment (R&D, brand, capability development) | Outcomes-based budgeting: funded based on multi-year return expectations rather than annual cost-benefit analysis | ZBB applied to long-term investments systematically undervalues them because the returns are realised over horizons longer than the budget cycle |
When to Consider ZBB: A Decision Guide
Zero-based budgeting is most appropriate in four specific organisational situations. Outside of these contexts, the management cost of full ZBB typically exceeds its benefits.
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🔄 Strategic transformation When the organisation’s strategy has shifted substantially and the cost base needs to be rebuilt around the new direction rather than the old one |
⚠️ Significant margin pressure When competitive pressure, market decline, or cost inflation is compressing margins and incremental cuts are no longer sufficient to restore financial health |
🏢 Post-merger integration After a merger or acquisition, when two legacy cost structures need to be rationalised and neither has more inherent legitimacy than the other |
📈 Rapid growth or scale-up When a fast-growing organisation has outgrown its cost structure and needs to build a scalable budget architecture from scratch rather than continuing to layer costs onto an ad hoc historical base |
Practical Implementation Considerations
For finance leaders considering a ZBB implementation, the following practical realities are consistently reported by organisations that have been through the process.
Start with a pilot area. Running full ZBB across the entire organisation simultaneously in the first year is the most common implementation error. The process is unfamiliar, the decision package quality is inconsistent, and the ranking discussions take longer than anticipated. Starting with one function or business unit for the first cycle builds capability, produces a playbook, and demonstrates value before the full rollout.
Invest in training before the process begins. Budget holders who have never built a decision package need to understand both the mechanics and the philosophy before they begin. Without this, decision packages are superficial and the ranking exercise is disconnected from genuine strategic thinking. CIMA (the Chartered Institute of Management Accountants) has published useful practitioner guidance on ZBB implementation at cimaglobal.com, including practical frameworks for decision package construction and ranking methodology.
Address the political dimension explicitly. ZBB surfaces trade-offs between departments that incremental budgeting keeps invisible. Some activities that have been funded for years will not survive the ranking exercise. The leaders of those activities will resist. Managing this resistance requires explicit leadership commitment, clear decision rights, and the cultural conditions in which honest challenge is possible. Without psychological safety, ZBB discussions produce performance rather than genuine cost scrutiny.
Define what “from zero” means for your context. Truly starting from zero in a large organisation with regulatory requirements, contractual commitments, and non-negotiable fixed costs is impractical. Most effective ZBB implementations define a “baseline minimum” of genuinely unavoidable costs and apply the zero-based discipline only to discretionary and semi-discretionary spending above that floor.
Conclusion: Choose the Discipline That Fits the Moment
The question is not which budgeting method is superior in principle. It is which approach will produce better decisions in your specific organisational context at this specific strategic moment.
If your cost base is stable, your strategy is well-embedded, and your management bandwidth is limited, incremental budgeting with periodic deep-dive reviews of specific cost areas is the more practical choice. If your organisation is facing strategic reinvention, significant margin pressure, or a legacy cost structure that has accumulated unchallenged for years, the analytical and cultural discipline of ZBB will surface opportunities that incremental adjustment never would.
The most financially disciplined organisations do not treat these as mutually exclusive. They apply the level of cost scrutiny that the nature of the spending warrants, reserving the full rigour of zero-based justification for the areas where the value of that challenge is greatest.
Related reading: The budgeting approach an organisation chooses determines what gets funded and what does not. Our article on how to align L&D with quarterly OKRs explores how learning and development budgets specifically can be structured to connect directly to measurable business outcomes rather than historical spending patterns.
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