Somewhere in your statements there is a line you have probably stopped reading. It's small, it's recurring, and it shows up every month like a tax you never voted for: interest charged. Add up a year of it, plus the monthly account fees, the wire fees and the annual card fee, and many freelancers are looking at several hundred dollars, sometimes a few thousand. Most of them never claim a cent of it. They assume that interest is just the cost of being short on cash, a personal failing with a number attached. For a self-employed person, some of that number is a business expense. Which part depends on one question the IRS cares about far more than the name on the card.

The question is what the money bought

A W-2 employee can't deduct interest on a card they used to buy a work laptop. Freelancers can, because they run a business and the tax code lets a business deduct ordinary and necessary expenses, and the cost of borrowing to fund the business is one of them.

But the IRS doesn't look at which card you swiped. It looks at what the borrowed money was spent on. The rules are called the interest tracing rules (Treasury Regulation 1.163-8T, if you want to read the source). The principle is simple: debt is classified by how you used the proceeds, not by the account it sits on or the collateral behind it.

So a charge for a monitor, a conference ticket or a month of ad spend is business debt. A charge for groceries, a flight to a wedding or a new couch is personal debt. Interest on the personal portion is not deductible for most people, and no label on the card changes that.

Why a mixed card is the hard case

If you have a dedicated business card, life is easy. Nearly every charge is a business charge, so nearly all the interest is deductible. You still shouldn't be careless, because a few personal lunches on it muddy the water, but the allocation is trivial.

The trouble starts with the card that does everything. Say your balance carries at 24% and you pay it down inconsistently. Some of the balance is client software, some is dinner, some is a vacation. Which dollars did you pay off? Which are accruing interest now?

The tracing rules handle repayments with an ordering convention: payments are generally treated as paying down personal debt first, then other categories, with business debt last. That means in a mixed account, a payment tends to retire the personal balance before the business one, which is the favorable direction for you. It also means the paperwork matters, because you need to be able to show how much of the balance originated from business purchases.

A workable method looks like this. Over the year, total the business charges on that card. Compare them with the total charges. Apply that share to the interest you paid, adjusting for any months where the mix was unusual. It isn't the only acceptable method, but it's a reasonable, explainable one, and a reasonable method you can document beats an aggressive one you can't.

Where the interest goes on your return

Freelancers report this on Schedule C. Interest on business debt that isn't a mortgage goes on line 16b, labeled other interest. Interest on a mortgage on business property goes on line 16a. (If you're deducting a home office, the mortgage interest question follows different rules, covered under the home office deduction rather than here.)

Bank and card fees don't have their own dedicated line, but they're deductible all the same. Monthly business checking fees, wire transfer fees, overdraft charges incurred for business reasons, and the annual fee on a business card typically go under other expenses, with a short itemized description on the supporting statement. Payment processor fees, such as the percentage a platform takes from each invoice, are also business costs and often fit under commissions and fees or other expenses.

What does not qualify

This is where people overreach, so it's worth being exact.

  • Interest on personal spending. A card used for your household doesn't become deductible because you are self-employed.
  • Interest and penalties on late taxes. Interest the IRS charges you, including the underpayment penalty on missed estimated payments, is not a business deduction. It's a cost of your tax bill, not of earning income.
  • The fee for paying taxes by card. The processing fee when you pay the IRS with a credit card is a personal cost attached to your tax payment. It doesn't move to Schedule C.
  • Fees on the personal half of a mixed account. Overdraft fees from a personal grocery run belong to your personal life, not your books.
  • Rewards, treated carelessly. Cash back and points earned on purchases are generally treated as a reduction in the price you paid, not as income. But if you deduct the full gross price of an expense and also keep a rebate, you've quietly double-counted. The simpler path is to deduct what you actually paid, net of rebates received.

Why a separate account makes this nearly free

Every question above gets easier when business and personal money don't share an account. If all the charges on one card are for the business, the tracing exercise collapses into a single line: the interest on that card is business interest. You can spend an hour in January untangling a mixed statement, or you can spend zero by drawing a line in advance.

There's also a human cost that doesn't show up on a return. When a balance is revolving at 22% and you don't know which part of it is the business, the whole thing becomes something you'd rather not look at. Separating it turns a vague dread into a number you can see, plan around and deduct.

Your next moves

  • Pull twelve months of statements for every card and bank account you use for work. Highlight each interest charge and each fee in a single color so you can see the real total.
  • Label each card as business, personal or mixed. For any mixed card, total the business charges and the overall charges for the year and write down the percentage. Save that note with the statements.
  • Open a dedicated business card or account for new spending, even if the old mixed card stays around while you pay it down. Starting today means next year's allocation is automatic.
  • Create an expense category for finance charges in your bookkeeping, separate from the item you bought, so interest and fees don't disappear into the purchase they came from.
  • Check your paying-taxes habit. If you cover estimated payments on a card, don't count the fee or the interest from that as a business expense, and consider whether a free bank payment would be cheaper.

Where Payday fits

The reason finance charges go unclaimed is rarely ignorance. It's that they're scattered across statements, tiny and unglamorous, and nobody sits down to add them up. Payday connects to your Stripe account and your bank, so the income side of your year, and the estimated payments that depend on it, stay in view all year rather than appearing as a surprise in April. When your quarterly numbers are already calculated, the deductions you gather, interest and fees included, simply lower a figure you've already been tracking. If that sounds useful, you can look at how it works at https://payday.lumenlabs.works.