Budgeting and forecasting

Why it matters

Without a budget every spending decision is made in isolation and every month is a surprise. With one, you know in advance how many sales you need, when cash will be tight and which costs are allowed to grow. The forecast turns that plan into an early warning system: if sales are tracking 15% under budget in month two, you can act in month three rather than discovering the shortfall at tax time. Lenders and investors also expect to see both, and a business that can explain its variances looks far more credible than one that cannot.

Budget and forecast are different tools

The budget is fixed for the year. It encodes your goals and the choices you made to reach them, and it does not move when reality disagrees with it; that disagreement is the point. The forecast is a living document. It starts as a copy of the budget and is updated as months close, contracts are won or lost and costs change. By month six the forecast might be quite different from the budget, and the difference tells you how the year is really going.

Keep them separate. If you edit the budget every time the forecast changes, you lose the yardstick and can no longer tell whether you are off plan because the plan was wrong or because execution was.

Build the budget from drivers, not last year plus 5%

The lazy budget takes last year and adds a percentage. It is quick and almost useless, because it hides the assumptions. A driver-based budget starts with the handful of things that actually produce revenue: number of customers, jobs per month, average sale, utilisation of staff, retention rate. Set each driver explicitly and let revenue fall out of the arithmetic. If the budget needs 30 jobs a month and you have never done more than 22, you have learned something before spending a dollar.

Costs split into two groups. Fixed costs (rent, insurance, salaries, software) are largely known and can be entered line by line. Variable costs (materials, subcontractors, merchant fees, commissions) should be budgeted as a percentage of the revenue they relate to, so they move with the sales plan. Add planned one-off items such as equipment or a marketing campaign in the month they will occur, not spread evenly.

• Start with revenue drivers and the assumptions behind each one; write them down.
• Enter fixed costs by month from contracts and last year’s actuals, adjusted for known changes.
• Budget variable costs as a percentage of revenue, using your real gross margin history.
• Place one-off and seasonal items in the right month so the cash view is honest.
• Include owner pay, loan repayments, tax and super so the budget reflects all cash demands.

Read variances like a detective

A variance is the difference between budget and actual. The number itself is less interesting than the reason. Revenue 10% under budget could mean fewer customers, smaller sales, slower delivery or a timing shift into next month; each has a different fix. Materials 5% over budget could be a price rise, waste, a mix of lower-margin jobs or a coding error in the books.

Set a threshold, say any line more than 10% or $2,000 from budget, and investigate only those. Write a one-line explanation for each. Over a few months you will see which variances are noise and which are trends, and you will stop being surprised.

Keep the forecast rolling

Each month, replace the forecast for the closed month with actuals, review the next three months closely and the rest lightly, and add a new month at the end so you always see twelve months ahead. Big changes, such as winning a major contract or losing a key staff member, trigger an immediate update rather than waiting for the quarter.

The forecast is where cash planning lives. Translate it into a bank balance by month, including BAS, super, loan repayments and drawings, and you have the long-range companion to a weekly 13-week cash forecast.

How to build and run a budget

1. Set three or four goals for the year Revenue, margin, headcount, a new location. The budget exists to serve these.
2. List revenue drivers and assumptions Customers, volume, price, utilisation. Sanity-check each against history.
3. Enter costs by month Fixed costs line by line; variable costs as a percentage of revenue; one-offs in the right month.
4. Stress-test the result Cut revenue 20% and see what breaks. Decide now what you would do.
5. Lock the budget and load it into your software Most accounting packages can report actuals against budget automatically.
6. Review monthly within ten days of month end Explain variances over your threshold in one line each.
7. Reforecast quarterly Update the forecast for what you now know and roll it forward twelve months.

Real-world example

An Adelaide gym budgets for a second site

Northside Strength is a 24-hour gym with 640 members paying an average of $62 a fortnight. The owner, Tom, wants to open a second site next year. Instead of adding 10% to last year, he builds the budget from drivers: current members and churn (about 4% a month), new joins per month from his marketing history, and the ramp-up curve a second site would follow. The model shows the new site needs 350 members to cover its rent and staffing, and that it will burn about $90,000 of cash before it gets there.

He locks the budget, then tracks it monthly. By month four, joins at the new site are running 20% under budget while the main site is on plan. The variance review shows the new site’s launch offer was priced too close to the main site and attracting few new locals. He adjusts the offer, updates the forecast, and pushes the break-even month out by two months, with the cash to cover it already arranged because the stress test had shown he might need it.

Common mistakes

• Last year plus a percentage It hides every assumption. Build from drivers so you can see what has to be true for the plan to work.
• Changing the budget to match reality You lose the yardstick. Update the forecast instead and let the budget show how far off you are.
• Spreading seasonal items evenly A flat budget looks fine on average and wrong in every actual month. Put costs and revenue where they happen.
• Forgetting cash items that are not expenses Loan principal, equipment purchases, BAS and drawings do not appear on a profit and loss but empty the bank.
• Reviewing too late or too rarely A variance you learn about three months later cannot be fixed. Review within ten days of month end.

KPIs to track

• Revenue variance to budget Actual revenue divided by budgeted revenue for the month and year to date. Explain anything beyond 10%.
• Gross margin versus budget Shows whether pricing and cost of sales assumptions are holding. A persistent gap means re-pricing or supplier work.
• Forecast accuracy How close last quarter’s forecast was to actuals. Improving accuracy means you understand the business better.
• Fixed cost coverage Gross profit divided by fixed costs. Above 1.0 you are covering overheads; the margin above that is your cushion.

Frequently asked questions

How detailed should a small business budget be?

Detailed enough to show each revenue line and each significant cost by month, on one or two pages. If you cannot explain every line in a sentence, it is too detailed.

Do I need special software?

No. A spreadsheet is fine to build it, and most cloud accounting packages let you load the budget and report actuals against it. Dedicated forecasting tools help once you have several revenue streams or sites.

What if I have no history to base it on?

Build it from first principles: how many customers can you realistically reach, what will they pay and what does it cost to serve them. Then treat the first year as a learning exercise and reforecast monthly.

How often should I reforecast?

Quarterly is a sensible minimum, monthly if the business is changing quickly or cash is tight, and immediately after any event that changes revenue or costs materially.

Key takeaways

• A budget is a fixed plan; a forecast is a living estimate. Keep them separate.
• Build the budget from drivers and written assumptions, not last year plus a percentage.
• Include cash items that are not expenses: loan principal, equipment, BAS and drawings.
• Investigate only variances above a threshold, and explain each in one line.
• Stress-test the budget before the year starts so the hard decisions are already made.