The short answer

With commission income, build minimum debt payments around your worst realistic month, not your average one, so a slow month never threatens a payment. Send a set percentage of every commission check above that floor toward extra debt payments, which naturally sends more in strong months and nothing extra in a lean one, without redoing the budget every time a check arrives.

Why an average month is the wrong number to budget around

Commission income varies, sometimes widely, from one month to the next. If required minimums are sized to an average month, a below-average month, which happens roughly half the time by definition, risks missing a payment. Anchoring the budget to a conservative floor instead avoids that risk entirely.

Finding your floor month

Look back at as many months of income history as you have, ideally a full year. The floor isn't the single worst month ever, caused by something unusual like an extended illness, it's a low but realistic month that could plausibly happen again. That number becomes the base the rest of the budget is built around.

Setting up the floor-plus-percentage system

Once the floor is set, the rest of the system follows from it.

  1. Gather 12 months of commission income if you have it, or as many as you have.
  2. Identify a low but realistic month, not an outlier caused by something unusual.
  3. Build required minimum payments and essential expenses to fit inside that floor amount.
  4. Pick a percentage of every commission check above the floor to send as an extra debt payment.
  5. Automate the percentage transfer the same day each commission check arrives.
  6. Revisit the floor amount once or twice a year as your income history grows.

Why a percentage works better than a fixed extra amount

A fixed dollar amount for the extra payment either goes unfunded in a slow month or leaves money sitting unused in a strong one. A percentage of whatever comes in above the floor scales automatically with actual income, so there's no monthly recalculation needed no matter how a given month turns out.

What to do the first year, before there's a full income history

Use whatever months of history are available, even if it's fewer than twelve, and lean conservative on the floor estimate until more real data builds up. Revisit the floor sooner than a full year out once several more months of income are on record.

Worked example · illustrative numbers

Example: setting a floor and a commission percentage

Ten months of income history range from $2,800 to $5,400, with a realistic low month around $3,000. Required expenses and minimum debt payments total $2,700, which fits inside that $3,000 floor with $300 to spare even in a slow month. They set 20% of every commission check above $3,000 as the extra debt payment.

In a month where the check is $4,500, the amount above the floor is $4,500 minus $3,000, or $1,500, and 20% of $1,500 is $300, so that month sends $300 extra toward debt. In a $3,000 floor month, there's nothing above the floor, so the extra payment is $0 that month, while minimums stay covered from the floor itself.

Put this into practice with Debtless

Debtless doesn't track commission checks or income at all. You'd manage the floor and percentage rule in your own budget, then enter whatever extra payment a given month produces into the Plan tab to see the updated projection.

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Common questions

What if a month comes in below even the floor?

That's what a cash buffer is for. Cover the gap from the buffer, keep minimum payments current, and treat a below-floor month as a signal to revisit whether the floor estimate needs to be set lower.

Should the percentage change over time?

It can, once more income history exists or debt balances shrink and priorities shift. There's no fixed percentage that fits everyone, since the right number depends on how much room the floor leaves above required expenses.

Does irregular income affect approval for future loans or refinancing?

Lenders generally look at income history and documentation when underwriting a loan, and specific requirements vary by lender. It's worth asking a given lender directly rather than assuming how commission income will be treated.

Sources & further reading

General education for U.S. readers, not individualized financial, legal or tax advice. Examples are hypothetical; lender terms and actual interest calculations can differ. Check your current statements and agreements.

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