How to budget on an irregular income

A budget works when income is predictable. When it changes every month, a normal budget fails on the first slow month. The fix is not a stricter budget. It is to separate when money arrives from when you spend it, and to watch your runway rather than one month’s earnings.

1. Pay yourself a base amount

Keep all your income in one holding account, and each month pay yourself a fixed “salary” from it into the account you spend from. Your spending account now behaves like a steady paycheck, and the holding account absorbs the ups and downs.

2. Set the base on a low month, not an average

Look at the last six to twelve months. A cautious base is the average of your three lowest months. For example, if you earned 60,000, 25,000, 90,000, 40,000, 55,000 and 30,000, the three lowest are 25,000, 30,000 and 40,000. Their average is about 31,700, so that is a safe base even though the overall average is about 50,000.

3. Fill the buffer before anything else

When a month pays more than your base, the extra goes first to your safety buffer until it reaches your target. People with irregular income usually need six to twelve months of essential costs. After that, extra income goes to goals, and then to anything optional. How many months to save explains how to choose a target.

4. Set tax aside when you are paid

If you owe tax on what you earn, move your estimate out of reach as soon as money arrives, so it is never counted as cash you can spend. Check the rules that apply to you.

5. Watch runway, not the month

A single month tells you little. Your runway, the days your cash would last at your current costs, tells you whether you are getting safer or less safe, and it smooths over uneven pay. A late client payment hurts less when you can see you still have 140 days.

6. Plan for the gaps

• Know which clients pay late, and treat their invoices as “not cash yet”.
• Keep your fixed costs as low as you reasonably can; they are what turns a slow month into a crisis.
• Write down your slowest months of the year, so they stop surprising you.

Start with the runway calculator, and read what financial runway is if the term is new.

Frequently asked questions

What should I base my budget on when income changes every month?

On a low but realistic month, not the average or the best. A simple rule is the average of your three lowest months from the last six to twelve.

What do I do with a month that pays more than my base?

Send the extra to your buffer first until it reaches your target, then to goals, then to anything optional.

Should I set tax money aside separately?

Yes, if you owe tax on what you earn. Move your estimate aside when you are paid, so it is never counted as spendable cash. Check the rules that apply to you.

This guide is general information, not financial advice. Your tax, debts and plans are your own, so check what applies to you.