Budgeting and forecasting — built from the operations, not last year plus ten
Reviewed by EverStone CPA · September 2026
A budget that was written in December and never looked at again is a document. A forecast that gets updated when the year turns out differently is a tool. Most businesses have the first and think they have the second.
EverStone CPA is a sole practitioner Chartered Professional Accountant firm in Abbotsford, British Columbia, working remotely with owner-managed businesses across Canada.
Quick answer: A useful budget is built from operating drivers — crews, seats, units, hours — rather than by adding a percentage to last year. It is then compared against actuals every month, and a rolling forecast carries the current best view forward so the number in front of you is never out of date.
Why last year plus ten per cent fails
Growing a prior year by a percentage assumes the business will do the same things in the same proportions, only more. That is almost never what happens. A contractor who wins one large project has a different cost shape, not a bigger one. An agency that hires two people has a step change in cost and a lag before the revenue arrives.
A driver-based budget starts from the things that actually generate the numbers: how many crews, how many billable hours, how many units at what margin, how many staff at what point in the year. The financial statement then falls out of the operating plan rather than being invented alongside it.
The practical benefit is that when the year goes differently, you can see which assumption was wrong. A percentage budget can only tell you that you missed.
The difference between a budget and a forecast
A budget is a commitment. It is set once for the year, it is what performance is measured against, and it does not move. Changing the budget mid-year to match what happened destroys the only benchmark you had. A forecast is a current best guess. It changes every time something material changes, and its job is to tell you what the rest of the year now looks like. Most businesses need a rolling forecast that always looks twelve months ahead, refreshed monthly or quarterly.Holding both at once is the point. The budget tells you how far off plan you are; the forecast tells you where you are actually going to land. Businesses that keep only one of the two are either flying blind or moving the goalposts.
What the work involves
Understanding the drivers. A conversation about how the business actually earns, which is usually the most useful hour of the process and often the first time the owner has had to state it explicitly. Building the model. Revenue by line, direct costs on their own logic, overheads by category, headcount with start dates, capital purchases with their timing, and the tax and payroll consequences that follow. Wiring it to the actuals. A budget that cannot be compared to the ledger without a manual exercise every month will not be compared to the ledger. The chart of accounts and the budget have to be built to match. Reforecasting on a rhythm. Monthly or quarterly, depending on how fast the business moves, with the variances explained rather than just displayed.Where this fits
Budgeting and forecasting is one of the deliverables inside a fractional controller engagement. It depends on a reliable close, so it is usually the second thing built rather than the first — a forecast on top of numbers nobody trusts is a spreadsheet with a false sense of security.
Where the decisions on top of the forecast are the difficult part rather than the forecast itself, that is fractional CFO work, and the two are often scoped together.
Common questions about budgeting and forecasting
We have never had a budget. Where do we start?+
How often should the forecast be updated?+
Should the budget change when the year goes differently?+
Can this be done for a business with seasonal revenue?+
Talk to a CPA about this
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