Every budgeting app opens by asking for your monthly income. If you’re self-employed, that question has no honest answer — and the budget you build on a made-up one breaks the first time reality disagrees. The fix isn’t a better guess. It’s not budgeting in fixed amounts at all.

Why the standard advice fails here

Conventional budgeting assumes a number arrives on a schedule. Rent is 30% of it, groceries are 12%, and so on. The whole structure rests on that number being roughly the same each month.

Take the number away and everything downstream stops working. You average your year and budget against the average — but you never actually earn the average. You earn well above it in three months and well below it in four. In the good months the budget says you have a surplus, so you spend it. In the thin months you’re “over budget” through no decision of your own, and after enough of those you stop opening the app.

The reframe

Stop asking “what do I earn each month.” Start asking “what happens to each payment when it arrives.” The first question has no answer. The second one always does.

The average is a month you never actually have

One illustrative year. $48,000 in total — an average of $4,000 a month.

2.1kJan1.4kFeb0.8kMar4.2kApr6.8kMay5.1kJun2.6kJul1.2kAug3.4kSep7.9kOct9.2kNov3.3kDec AVERAGE $4,000
At or above average Below average
7 of the twelve months come in under the average and only 5 above it. A budget built on $4,000 is wrong in every single month of this year — too generous most of the time, too mean the rest. Illustrative figures, not a real customer’s.

Step one: find your baseline monthly expenses

Your baseline is what a month costs you if you earn nothing at all. Add up only the unavoidable:

Not restaurants. Not subscriptions you’d cancel in a bad month. Not travel. You’re pricing survival, not your current lifestyle.

This single figure is the most useful number an irregular earner can have. It tells you what a dead month actually costs — which means it tells you how big a buffer you need, and how bad a bad month can get before it’s a real problem.

Step two: build the buffer in months, not dollars

The usual guidance is three to six months of expenses. For irregular income, lean toward six — and count it in baseline months, not as a round dollar figure. “I have $12,000 saved” tells you very little. “I have five months of baseline” tells you exactly how long you can go with nothing coming in.

Until that buffer exists, it’s the first claim on any surplus. It isn’t glamorous, and it’s the thing that converts a frightening month into an inconvenient one.

A market trader laughing as she hands a paper bag of vegetables to a customer, a card reader on the table in front of her.
A good Saturday and a washed-out one are the same job. Percentages are what let both of them be handled by a rule you set once.
A month’s worth of invoices and payment slips spread unevenly across a desk, some large, most small.
This is the shape of a self-employed year: a few big months carrying several thin ones. Percentages survive that shape. Fixed monthly amounts do not.

Step three: split every payment by percentage

Here’s the actual mechanism. Instead of committing to monthly dollar amounts you can’t honor, decide once what share of any incoming payment goes where. Then apply it to whatever lands.

A starting point — adjust to your life

Tax — set aside immediately25–30%
Needs — baseline expenses50%
Wants — the discretionary part20%
Savings — buffer first, then goals10%
Investment — long-term, retirement5%

Those don’t sum to 100% because tax comes off the top first — it was never your money. Split what remains.

The elegance is that the rule doesn’t care about the size of the payment. A $12,000 month and a $900 month are handled identically. There’s no such thing as being “over budget,” because the budget is a ratio, not a ceiling. In a big month every category gets more, including the buffer. In a thin month everything scales down and the buffer covers the gap.

Do the split on the day the money lands

Not weekly. Not at month end. The moment a payment arrives, move the tax share and the savings share out of the account you spend from. Money that’s still sitting in your checking account is money you’ve already half-spent, whatever the spreadsheet says.

Optional: pay yourself a salary

Once the buffer is real, a lot of self-employed people go one step further: income lands in a business account, and on the 1st of each month they transfer a fixed amount to their personal account. That’s their paycheck.

Good months build the business account up. Thin months draw it down. Personal life sees a steady number and gets to use ordinary budgeting, because the irregularity is absorbed one layer up.

This only works with a buffer behind it — otherwise you’re paying yourself money that isn’t there. But once it does work, it’s the closest thing to a solved problem in self-employed finance.

What to actually do this week

  1. Add up your baseline. One number, twenty minutes.
  2. Work out how many baseline months you currently have saved.
  3. Pick your percentages. Start with the table above and adjust.
  4. Open a separate account for tax if you don’t have one. Same bank is fine — it just can’t be the account you spend from.
  5. Apply the split to the very next payment that arrives, before you do anything else with it.

That’s the whole method. No forecasting, no pretending you know what March looks like.

This is what BrassWell is built around

Set your percentages once. Every payment splits automatically, with tax carved off before you can spend it.

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Questions, answered

How do you budget with an irregular income?

Budget in percentages rather than fixed dollar amounts. Decide what share of any incoming payment goes to tax, needs, wants, savings and investment, then apply those same percentages whatever lands. A big month and a thin month are handled by the same rule, so the plan never breaks.

What is a baseline number and why does it matter?

Your baseline is the total of everything you must pay in a month that has no income at all — rent, insurance, utilities, food, minimum debt payments. It is the single most useful figure for irregular earners because it tells you what a bad month actually costs, and therefore how much buffer you need.

How many months of buffer should a self-employed person keep?

Three to six months of baseline expenses is the common guidance, and the irregular the income the closer to six it should be. Build it in baseline-months rather than a round dollar figure, because the point is how long you can survive with nothing coming in.

Should I pay myself a fixed salary from my business?

Many self-employed people do, and it works well if you have enough buffer to cover the gap in thin months. Income lands in a business account, and you transfer a consistent amount to yourself each month. It converts irregular income into a regular paycheck, but only once the buffer exists to absorb the difference.

Sources

  1. Estimated taxes — IRS. Why the tax bucket comes off the top: nobody withholds it for you, and the bill arrives four times a year.
  2. Self-employed individuals tax center — IRS. What counts as net profit, which is the figure the percentages apply to.

General information, not financial advice. The percentages here are a common starting framework, not a recommendation tailored to your circumstances — your debts, dependants, health costs and local cost of living all change what’s sensible. Read more on the tax side of this.