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How to avoid Missouri underpayment penalty?

Missouri charges an underpayment penalty when you owe more than $100 at tax time and didn’t pay enough during the year. The penalty is essentially interest on what you should have paid earlier. Avoiding it comes down to paying estimated taxes or adjusting withholding so you stay ahead.

The safe harbor rules are your protection. You can avoid the penalty by paying either 100% of your prior year Missouri tax liability or 90% of your current year tax. For most small business owners with variable income, the prior year method is safer because you already know that number. Calculating 90% of current year tax requires accurately predicting your income, which isn’t always possible when business fluctuates.

Quarterly estimated payments are due April 15, June 15, September 15, and January 15. You can pay online through the Missouri Department of Revenue or mail vouchers with your payment. A Mid-Missouri bookkeeper can help you calculate the right amount based on your prior year tax or projected current year income.

If you receive W-2 wages from your own business or another employer, you can increase withholding instead of making estimated payments. Some business owners bump up their payroll withholding to cover anticipated tax from business income. This works well if your income is fairly predictable from year to year.

The penalty calculation isn’t straightforward. Missouri computes it quarterly, so an underpayment in Q1 accumulates more penalty than one in Q4. If you have a big income spike late in the year, you might owe estimated taxes immediately rather than waiting for the next quarterly date.

Keeping your books current throughout the year helps you know where you stand. When your monthly bookkeeping stays up to date, you can see your actual income and estimate your tax liability with real numbers instead of guessing. Many business owners get hit with underpayment penalties simply because they didn’t realize how profitable their year was until they sat down with their accountant in March.

The goal is having no surprises at tax time. Just a smooth filing with taxes already paid throughout the year.

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More Questions

Does a plumber need professional liability?

Most plumbers don't need professional liability insurance. General liability covers the claims plumbers actually face. Professional liability becomes relevant only if you're doing design work or consulting.

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How do I set up payroll in Missouri?

Setting up Missouri payroll requires an EIN, state tax registration, withholding setup, and local earnings tax registration for Kansas City or St. Louis employees. Most small businesses use payroll software or outsource it entirely.

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Is a bookkeeper different than an accountant?

Yes. Bookkeepers handle the ongoing work of recording transactions, reconciling accounts, and keeping your books current. Accountants handle tax preparation, financial analysis, and strategic advice. Most small businesses need both.

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What happens if you don't do bookkeeping?

Problems start small and compound quickly. You lose track of expenses, miss tax deductions, make decisions without knowing your real numbers, and eventually face a costly cleanup when you need accurate books for a loan or tax filing.

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Is QuickBooks Online good for general contractors?

Yes, QuickBooks Online works well for general contractors when it's configured for job costing. The software handles project tracking, subcontractor payments, and progress billing effectively with proper setup.

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Does your accountant need all your receipts?

Yes, your accountant needs receipts, though the IRS only requires them for expenses over $75. The real value is that receipts provide context that bank statements can't, making your books more accurate and your deductions defensible.

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Full-charge bookkeeping for Mid-Missouri's small businesses. We serve owners from the Lake to Jeff City and Columbia who need their numbers to be as reliable as their work. Local, certified, efficient, and precise.

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