Business Budget Calculator

Percentages keep costs proportional as you grow.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

Currency

Annual revenue

Cost of goods

Marketing

Payroll

Fulfilment and shipping

Overheads and software

Target net margin

Net margin at this budget

10%

$120,000 of profit

Total allocated90%

Marketing budget$168,000

Payroll budget$192,000

Below target by2%

The allocations total 90%, leaving 10% against a 12% target. Something has to come down by 2% of revenue: marketing and payroll are usually where the room is.

How the Business Budget Calculator works

Budgeting as percentages of revenue keeps costs proportional as the business grows, which fixed budgets do not. The allocations also have to leave the target net margin, if they total more than they should, something has to come down before the year starts.

Also known as: annual business budget planner · operating budget calculator · small business budget template

Building a budget that gets used

A budget is a plan expressed in money, and its value comes from being compared against reality rather than from being produced.

The structure that works is a line per meaningful cost category, phased by month, with a total. Categories should be granular enough to act on and coarse enough to maintain: fifteen to thirty lines suits most small businesses.

The most common failure is building a budget for a funding application and never referring to it again. A budget that is not reviewed monthly is a document rather than a tool, and the effort that went into it is wasted.

Zero-based against incremental

Incremental budgeting starts from last year and adjusts. It is quick and it carries forward every cost that has ever been incurred, including the ones nobody would approve today.

Zero-based budgeting starts from nothing and justifies each line. It is far more work and it reliably finds costs that have outlived their purpose.

The practical compromise is incremental most years with a zero-based review periodically, or zero-based on the discretionary categories only. Most small businesses that have never done it find 10% to 20% of the cost base is doing nothing, and the first review is the one that pays.

Phasing, and why flat budgets fail

Dividing an annual budget by twelve produces a monthly figure that describes no actual month, and variance against it is meaningless.

Costs are lumpy: insurance annually, accountancy at year end, software renewals on their own dates, stock purchases before the season. Phasing them to when they actually occur is what makes the budget comparable to the bank account.

It also produces a cash requirement by month, which is the output that matters. A budget that balances over a year while requiring £40,000 more cash in September than exists is a budget that does not work, and only the phased version shows it.

Variance, and what to do with it

Monthly variance analysis compares budget to actual and asks why they differ. The question is more useful than the number.

Variances split into price and volume: spending more because prices rose is a different problem from spending more because activity was higher. Separating them tells you whether the variance is a problem or a consequence of doing more business.

A threshold prevents the exercise consuming the month. Investigating variances above a stated percentage and a stated amount focuses attention on what matters, where reviewing every line produces fatigue and eventually abandonment.

Contingency, and where to put it

Budgets should carry a contingency, and where it sits determines whether it survives. A contingency spread across every line disappears, because each line quietly uses its share.

A single contingency line, held centrally and released deliberately, survives. It also makes the decision visible: releasing contingency is a choice someone made rather than a drift.

Five to ten percent of the discretionary budget is a reasonable starting figure, higher for a business with volatile costs or an ambitious plan. A budget with no contingency is a budget that will be wrong in the first quarter and will then be ignored for the rest of the year.

Where to go next

The Business Budget question rarely arrives on its own. These are the ones that usually come with it:

Cost Structure Calculator — Step costs are the trap in capacity planning.
Profit Goal Calculator — Tax comes off the profit.
Marketing Budget Calculator — What actually reaches media after people and tools.
Etsy Fee Calculator — Every Etsy fee on one sale, itemised.

Not financial advice. Marketplace fees change, and they vary by country, plan and seller status. Every rate here is an editable default, not a quoted price, check the platform's current fee schedule before you price a product against it. This is not tax or business advice.

Frequently asked questions

What percentage of revenue should each cost be?

It varies by model, but ecommerce commonly runs 40-55% cost of goods, 10-20% marketing, 10-20% payroll and 5-15% fulfilment. Your own history beats any benchmark.

Why budget as percentages?

Because most costs scale with revenue, so a percentage budget stays valid as the business grows. A fixed budget is wrong within a quarter in a growing business.

What if the percentages exceed 100 less my target?

Then the plan does not produce the target margin. Marketing and payroll are usually where the room is, and deciding that in advance is easier than discovering it in month eight.

Should the budget flex during the year?

Percentage budgets flex automatically with revenue. What should not flex is the target margin, that is the constraint the whole budget exists to protect.