One Business, More Than One Way to Plan

Why the best budgeting process combines the right methodologies, rather than relying on just one.

Should your organisation use top-down budgeting or bottom-up budgeting? What about driver-based planning, centrally defined assumptions or scenario modelling?

For many organisations, the answer is not to choose one budgeting methodology, but to combine several. Different departments have different planning requirements, yet their budgets, forecasts and assumptions must ultimately come together in one coherent financial plan.

The challenge is to give each area of the business the flexibility to plan in the way that makes sense for its operations, while maintaining the governance, consistency and visibility finance needs.

An integrated financial planning process makes this possible.

One Organisation, Different Budgeting Requirements

Consider the different questions being asked across a typical organisation.

Sales may be asking how much it can sell. Workforce planning is concerned with the people the organisation will need. Operations need to understand what must be produced or delivered. Department managers need to determine the resources required to run their areas. At executive level, the focus is on what the organisation needs to achieve.

These are very different questions, driven by very different information, but they are not separate planning exercises. Ultimately, they all need to come together in the same financial plan.

That is why one budget does not need to mean one methodology.

Some numbers may be built from the detail. Others may be determined at a higher level. Others should be calculated from business drivers and assumptions rather than manually entered at all.

For many organisations, combining budgeting methodologies is a far better reflection of how the business actually operates.

Bottom-Up Budgeting: When the Detail Matters

Bottom-up budgeting is valuable when the people closest to the expenditure or activity know the detail best.

Finance can establish the structure, timetable and rules, but it cannot necessarily know that a department has training planned for June, that equipment needs replacing, that a marketing campaign is scheduled for later in the year, or that a new project will require additional resources.

Allowing departments to participate in building their budgets does more than improve the detail. It creates ownership.

The budget is no longer something finance has imposed on the department. The people responsible for the numbers have participated in creating them, which can strengthen accountability when actual performance is later reviewed against budget.

Top-Down Budgeting: Aligning Plans with Strategy

There are also situations where the organisation already knows where it needs to get to.

The board may have set a revenue growth objective. Operating costs may need to stay within a defined limit. A margin needs to be protected, or headcount may need to remain within certain parameters.

This is where top-down budgeting becomes important.

Strategic direction and centrally determined values can be translated through the organisation, from divisions to departments and cost centres. But top-down and bottom-up planning do not need to compete with one another.

Top-down planning can establish what the organisation needs to achieve. Bottom-up planning can help determine what it will take operationally to achieve it.

Where the two do not align, an important business conversation begins. Are the targets realistic? Are sufficient resources available? Do the operational plans support the organisation's strategic objectives?

Bringing both perspectives together helps finance identify these gaps and support more informed decisions.

Assumption-Based Budgeting and Driver-Based Planning

Then there are areas where manually entering a budget number may not make sense at all.

If rent increases with inflation, the relevant inflation assumption should drive the calculation. If imported costs are affected by exchange rates, the exchange-rate assumption should influence the financial result.

Workforce costs can be calculated using headcount, salaries, recruitment dates and increase assumptions. Revenue can be driven by a combination of price and volume.

The question changes from:

"What number should we budget?"

to:

"What assumptions and business drivers determine that number?"

This gives finance a much stronger understanding of the relationship between operational activity and financial performance. Instead of treating budget values as isolated figures, finance can understand what drives them and how changes in one area may affect another.

Historical information and machine learning can increasingly support the development of predictive assumptions as well, giving finance additional information to consider when preparing budgets and forecasts.

Combining Budgeting Methodologies in One Financial Plan

This is where integrated financial planning becomes particularly powerful.

Imagine a single organisational budget where:

• Sales works towards a top-down revenue objective but uses selling price and volume assumptions to calculate the detail.
• Workforce planning calculates costs using existing employees, vacancies, recruitment dates, salaries and increases.
• Marketing develops its plan from the bottom up, using individual campaigns, events and digital spend.
• Operations plans using activity levels or volume drivers.
• Corporate departments build detailed expenditure budgets while applying common assumptions, such as inflation, to selected costs.

These are not five different budgets. They are different methodologies being used within one organisational budget.

Each area can plan according to its operational requirements while contributing to the same overall financial plan. Finance can bring those plans together, assess whether they support the organisation's objectives and understand the implications for the business as a whole.

Integrated Financial Planning Without Fragmentation

Supporting different planning methodologies is only part of the challenge.

If each area manages its plan through separate spreadsheets and disconnected models, finance can quickly end up with different versions, inconsistent assumptions, manual consolidation and limited traceability.

The objective should not be to remove flexibility. Each area of the business should be able to plan in the way that makes sense for its operations.

The challenge is keeping those different approaches connected.

Whatever methodology is used to create an individual number, finance ultimately needs one financial plan.

This is where a governed financial planning environment becomes essential.

Finance still requires security, workflow, approvals, auditability, version control and accountability. Common assumptions need to be applied consistently where appropriate, and the organisation needs a common understanding of its structures and accounts.

Different parts of the business can plan differently, but those plans should ultimately produce one coherent financial view.

Scenario Planning and Financial Modelling

Once assumptions and their relationships to the financial plan are defined, scenario modelling becomes much more meaningful.

Finance can ask what happens if inflation rises, the exchange rate changes, headcount increases, pricing moves or volumes fall.

Rather than changing individual spreadsheet cells and hoping to understand the combined effect, the organisation can change a business driver and see how the impact flows through the financial model.

That is an important shift.

We are no longer simply changing cells. We are modelling the business.

Scenario planning allows organisations to explore different possibilities before committing to a course of action. Finance can assess the potential impact of different assumptions, compare outcomes and help the business understand the financial implications of its decisions.

It also allows finance to move beyond explaining what happened towards helping the business understand what could happen next.

How AI and Machine Learning Support Financial Planning

AI does not replace the planning methodologies or the financial expertise behind them. It can, however, help finance work with information more intelligently.

Machine learning can examine historical data, trends and patterns to help identify likely outcomes and support predictive assumptions. Natural-language enquiry allows finance teams to begin with the business question rather than always needing to know which report or screen contains the information.

AI can also help explain results by identifying the drivers behind changes, highlighting material variances and drawing attention to areas that deserve further investigation.

The principle remains important:

AI supports. Finance validates. The business decides.

Technology can help teams access relevant information faster and challenge assumptions more effectively, but finance continues to provide the context, judgement and validation required before decisions are made.

The value lies not in using AI for its own sake, but in helping finance ask better questions, assess the information available and support sound business decisions.

The Benefits of an Integrated Budgeting Process

Ultimately, bottom-up budgeting, top-down planning, assumptions, scenarios and AI are not the end goal.

The goal is a better planning process.

Reducing dependency on disconnected spreadsheets, manual consolidation and repeated checking gives finance something incredibly valuable back: time.

Time to analyse the budget rather than simply assemble it.

Time to challenge assumptions.

Time to understand the forecast.

And time to work with the business on what the numbers actually mean.

An integrated process also supports collaboration, because departments participate directly in planning while finance retains the necessary governance and control. It can strengthen accountability because people understand and take ownership of their numbers. It can also reduce the time required to complete the planning cycle.

IDU clients have reduced budget and forecast processes by up to 70%.

The opportunity is to spend less time gathering, consolidating and checking numbers, and more time using financial information to understand performance and support decisions.

One Business. More Than One Way to Plan.

There is no single profile of an IDU customer.

IDU is used across a diverse range of industries, with different business models, different drivers and sometimes highly specific calculations. What those organisations have in common is the need to bring their people, methodologies and calculations together into one controlled financial planning environment.

That is the philosophy behind IDU.

Organisations should not have to choose between bottom-up, top-down or assumption-based planning. Different methodologies can coexist within the same planning environment and, importantly, within the same organisational budget, while finance retains control of the structure, assumptions, governance and financial outcome.

The right financial planning environment gives each area the flexibility it needs while helping the organisation maintain one consistent view of its financial position and plans.

One business. More than one way to plan. One governed financial plan.

Frequently Asked Questions

What is the difference between top-down and bottom-up budgeting?

Top-down budgeting starts with strategic targets or financial limits set by senior management and translates them into budgets across the organisation. Bottom-up budgeting involves departments building their budgets from operational requirements and detailed expenditure plans. Combining both approaches helps align strategic objectives with operational realities.

Can an organisation use top-down and bottom-up budgeting together?

Yes. An organisation can set revenue targets, cost limits or other financial objectives from the top down while allowing departments to develop detailed budgets from the bottom up. Both approaches can be brought together within one governed financial planning process.

What is assumption-based budgeting?

Assumption-based budgeting uses defined business drivers and assumptions to calculate financial outcomes. For example, workforce costs can be calculated using headcount, salaries and recruitment dates, while revenue can be modelled using selling prices and sales volumes.

How does scenario planning improve budgeting and forecasting?

Scenario planning allows finance teams to assess how changes in assumptions, such as inflation, exchange rates, headcount, pricing or sales volumes, could affect financial results. This helps organisations evaluate different possibilities before making decisions.

How can financial planning software support different budgeting methodologies?

Financial planning software can provide a shared environment in which departments use different budgeting approaches while working with common financial structures, assumptions, workflows, approvals and version controls. This helps finance maintain oversight without forcing every department to plan in the same way.

Bring Your Planning Processes Together

Want to see how different budgeting methodologies can work together in practice?

Explore IDU's financial planning and budgeting solution to discover how your organisation can bring budgeting, forecasting, scenario modelling and reporting together in one controlled environment.