--- title: "Common Bookkeeping Mistakes and How to Fix Them | MCC" description: "The bookkeeping mistakes that distort small business reports most often, with plain steps to find and correct each one before tax time." url: "https://mcc-solutionsnj.com/bookkeeping/guides/common-bookkeeping-mistakes-and-how-to-fix-them" --- Bookkeeping guide · Updated October 12, 2026 # Common Bookkeeping Mistakes and How to Fix Them Almost every set of small business books has errors. The goal is not perfection but catching the ones that matter. These are the mistakes that show up most often and what to do about them. By [Matthew Coleman](/about), MCC Solutions **Quick answer.** The most common bookkeeping mistakes include mixing personal and business spending. Going forward, use separate accounts; for past entries, move personal items to owner draws and business items paid personally to owner reimbursement or contributions, with a note. Want this handled for you? Monthly bookkeeping, cleanup and year-end close for small businesses. Start with a free health check of your books. [Free health check](/bookkeeping/health-check)[Get a quote](/bookkeeping/#interest) **Related:** [Closing entries and retained earnings](/bookkeeping/guides/closing-entries-and-retained-earnings) · [Void vs delete a transaction](/bookkeeping/guides/voiding-vs-deleting-transactions) · [NJ 1099 contractor rule (ABC test)](/bookkeeping/guides/nj-independent-contractor-rule-abc-test-2026) **Free tools:** [Are my books ready for taxes?](/bookkeeping/is-my-quickbooks-ready-for-taxes) · [Profit margin and markup calculator](/bookkeeping/profit-margin-and-markup-calculator) [![Intuit ProAdvisor Gold tier badge](/img/credentials/intuit-proadvisor-gold.png)](https://proadvisor.intuit.com/app/accountant/search?searchId=matthew-coleman77)Gold tier in Intuit's ProAdvisor program. [See my Intuit listing](https://proadvisor.intuit.com/app/accountant/search?searchId=matthew-coleman77) Keeping your own books? Tallyfinch does invoices, bank import and reports on your computer. [See Tallyfinch](/bookkeeping/mcc-books-downloadable-bookkeeping-software) ## Mixing personal and business Paying for groceries from the business account or a business bill from a personal card muddies profit and creates tax questions. The fix going forward is separate accounts. For past entries, move personal items to owner draws and business items paid personally to owner reimbursement or contributions, with a note. ## Skipping reconciliations Without a monthly reconciliation, duplicates, missing deposits and bank errors pile up. When you finally reconcile, a year of differences is hard to untangle. Do it monthly, and when behind, reconcile the oldest months first and work forward. Never fix a difference with a plug entry to force a match. Find the cause. ## Miscategorizing Common examples are loan principal in expenses, equipment in repairs, owner deposits in income and sales tax as revenue. Run an expense report by vendor and a list of unusual accounts to find them. Correct each at the transaction level where possible. Where a transaction has a bank match, edit the category rather than creating a journal entry. ## Want us to handle it? We get behind or messy books current, tell you what we found, and hand you a clean starting point, in QuickBooks, Xero or Excel. **Price:** Free review of your books first, then a written quote before any work starts. [Get a free review and quote](/bookkeeping/#interest) [How catch-up and cleanup work](/bookkeeping/catch-up) ## Duplicates and missing records Duplicates arise when a bill is entered and a bank feed also creates an expense. The fix is to match feed items to existing bills. Missing records come from cash sales, unrecorded transfers and untracked refunds. Use the deposit detail and statement as a check on revenue. Check sales against deposits each month, allowing for fees and timing. ## Ignoring tax liabilities Payroll taxes and sales tax collected belong to the government, not the business. If they sit in the bank without being paid, the cash looks like yours. Set up liability accounts and compare the balance with filings. Pay on time, since penalties compound. If you discover unfiled returns, speak to a CPA or enrolled agent about the right approach. ## Weak documentation and delayed work Missing receipts, vague memos and months of backlog are the root of many other mistakes. Set a weekly fifteen-minute routine for receipts and categorizing. Backlogs get harder every month. When you find an error in a closed year, do not edit silently. Record a correcting entry, note it, and ask your tax preparer whether an amended return is needed. If you inherit a mess, tackle it in a sensible order. First, reconcile bank and card accounts so cash is right. Second, clear uncategorized balances. Third, check receivables and payables against actual open items. Fourth, review loans, payroll and sales tax liabilities. Fifth, review equity and fixed assets. Working top down from cash means each later step builds on solid ground and your fixes do not get undone by earlier errors. Finally, write down each fix you make, with the date and reason, in a running log. It helps your accountant, and it shows you which mistakes recur so you can change the habit behind them. ## Common questions **How do I know my books are wrong?** Red flags include a balance sheet that does not match the bank, large uncategorized balances and profit that does not fit your cash experience. **Should I fix old errors myself?** Small ones, yes. Larger or tax-related ones should be reviewed by a bookkeeper or CPA. **Can software prevent these mistakes?** It reduces them, but review and reconciliation are still needed. This guide is general information, not tax, legal or accounting advice. Rules, fees and due dates change; check with the IRS, the NJ Division of Taxation or a licensed professional for your situation. Let us handle it [### Monthly bookkeeping Categorizing, reconciling and monthly reports, with cleanup, payroll and NJ filings available. Bookkeeping →](/bookkeeping/) [### QuickBooks Online Monthly bookkeeping, cleanup and reconciliation in QuickBooks Online for New Jersey small businesses. Your account stays in your name. QuickBooks →](/bookkeeping/software/quickbooks-online)[### Wave Bookkeeping help for Wave users in New Jersey, and when it makes sense to outgrow Wave. Cleanup, reconciliation and moves to another platform. Wave →](/bookkeeping/software/wave)[### Xero Bookkeeping and reconciliation in Xero for New Jersey small businesses, including cleanup and moving from spreadsheets or another program. Xero →](/bookkeeping/software/xero) More guides - [How to Hire a Bookkeeper: What to Ask and Check](/bookkeeping/guides/how-to-hire-a-bookkeeper) - [Managing Your Bookkeeper: Reviews and Communication](/bookkeeping/guides/managing-your-bookkeeper-after-you-hire) - [Bookkeeping for a Side Hustle: Start Simple](/bookkeeping/guides/bookkeeping-for-a-side-hustle) - [Tracking Mileage and Vehicle Expenses for Business](/bookkeeping/guides/tracking-mileage-and-vehicle-expenses) Free tool - [Bookkeeping health check](/bookkeeping/health-check) [All guides](/bookkeeping/guides) Reach small business owners, freelancers and bookkeepers who read this guide: [advertise here](/advertise#bookkeeping). Do it yourself ### Month-End Close Workbook A real month-end close in one Excel file. It tells you when a rec does not tie, which variances still need an answer, and when the period is ready to lock. [See what's inside ($19)](/toolkits/month-end-close-workbook)14-day full refund ## Rather have us keep the books? Ask for a quote. [Get a Quote](/bookkeeping/#interest)[Call (908) 444-6373](tel:+19084446373)