What Was That $1,800 Charge? How to Untangle Business and Personal Money Before Tax Time

Someone asks what that $1,800 charge in June was, and you stare at it with no idea. The fix has two halves: stop the mixing from today with a separate account and card, then clean up the past in one focused pass, biggest charges first. Anything you still can’t explain stays out of your deductions.

A supplies order? A personal trip? A client refund? If your statement looks like a junk drawer, you’re in good company. Mixing business and personal money is one of the most common self-employed problems, and one of the most fixable.

Why it matters for taxes

On Schedule C you report business income and subtract business expenses; what’s left is taxed. Every deduction has to be something you can explain. If you can’t, you either skip it and overpay, or claim it and hope nobody asks. At roughly 25 to 30 cents of tax per dollar of profit, an unexplained $1,800 business expense left out costs about $500.

Mixed accounts also hide your real profit, so you can’t tell how much to set aside. When tax prep feels like an archaeological dig, the cause is almost always one pile of money doing every job.

Step 1: Pick a cutoff date and stop the bleeding

You don’t have to fix the past to fix the future. From today (or the first of next month):

• Run all business income and expenses through a separate business checking account.
• Use one card only for business spending.
• Pay yourself by transfer, on a schedule. For a sole proprietor that’s an owner’s draw, not an expense.

Our post on what one bank account really costs you explains why this is the simplest fix of all.

Step 2: Clean up the past in one pass

1. Download 12 months of statements from every account and card you used.
2. Make three columns: Business, Personal, Not sure.
3. Start with the big ones. Anything over $250 first: they matter most and are easiest to trace.
4. For “Not sure,” look for evidence: email receipts (search the merchant), calendar entries, invoices, texts, order confirmations.
5. Still unknown? Leave it out. You can add a deduction later if you find proof. Don’t guess.

Paid cash with no receipt? See how to document cash purchases.

Step 3: Handle the gray areas honestly

• Phone and internet: deduct the business share by a reasonable percentage.
• Car: the standard mileage rate (72.5 cents a mile for the first half of 2026, 76 cents from July) or actual costs, with a mileage log either way.
• Home office: only a space used regularly and exclusively for the business.
• Meals and subscriptions: only the business part, and only if you can explain it.

Write one line beside each gray-area entry (“software for client scheduling”) while you still remember.

Step 4: A tiny system you’ll actually keep

• Ten minutes a week labeling new charges Business or Personal.
• Photo of each receipt the day you get it.
• At month end: income in, expenses out, profit.

Money you already moved around

Paid a personal bill from the business account, or the reverse? Not a disaster. Record it as an owner’s draw or an owner’s contribution rather than an expense. The goal is that your expense list only contains real business expenses. See which Schedule C line each expense goes on.

This is why Toozi exists

Nobody tells you about separate accounts until you’ve suffered through a few tax seasons. Toozi keeps your numbers sorted as you go: text what you earned and spent, and when someone asks about a charge, the explanation is already there.

The Toozi team

Toozi isn’t your CPA and this isn’t formal tax advice. It’s the plain-English version. What counts as deductible depends on your situation, so check current IRS guidance or talk to a pro.