A good monthly bookkeeping routine for an Ontario small business means reconciling every bank and credit card account, categorizing transactions, chasing unpaid invoices, reviewing your HST position, confirming payroll remittances, saving receipts, and reading your financial statements before the 15th of the following month. Do those seven things consistently and tax season stops being a scramble.

Why Monthly Bookkeeping Matters More in Ontario Than You Think

Let’s be honest: most business owners didn’t start a company because they love spreadsheets. You started it because you’re good at something, whether that’s building, baking, designing, consulting or fixing things. Bookkeeping is the chore that sits at the bottom of the pile until a deadline shows up.

Here’s the problem. In Ontario, small businesses deal with a stack of obligations that all run on different clocks: 13% HST, payroll source deductions, WSIB premiums, corporate tax instalments, and year-end filings with the Canada Revenue Agency (CRA). Miss one and you can face penalties and interest that never needed to exist.

At TJ Marshall Tax & Accounting, we see the same pattern every year. Owners who spend one focused hour a week and a couple of hours at month-end rarely panic in April, or in the months before a corporate filing deadline. Owners who let it slide for six months usually end up paying more in accounting time, cleanup fees and avoidable tax.

So here’s the checklist we wish every Ontario small business owner had taped to their monitor. Use it as written, or adapt it to your industry.

The Monthly Bookkeeping Checklist for Ontario Small Businesses

1. Reconcile every bank and credit card account

This is the foundation. Compare your accounting software against your actual bank and credit card statements and make sure every line matches. If something doesn’t, find out why now, not in March.

What to watch for:

• Duplicate transactions
• Missing deposits from payment processors like Square, Stripe or Shopify
• Personal expenses that slipped onto the business card
• Bank fees and interest that never got recorded

If you take one thing from this post, make it this: an unreconciled account means every report built on it is a guess.

2. Categorize all transactions correctly

Miscategorized expenses are the most common error we fix when we clean up books for small businesses across Ontario. Meals get coded as office supplies. Equipment purchases get expensed when they should be capitalized. Owner draws get recorded as wages.

Set up bank rules in your software for recurring vendors, then review anything it can’t place. Keep your chart of accounts simple. Thirty well-chosen categories beat a hundred confusing ones.

3. Record and follow up on invoices

Cash flow is where small businesses live or die. Every month, review your accounts receivable aging report. Anything over 30 days deserves a polite reminder. Anything over 60 days deserves a phone call.

On the other side, check your accounts payable so you’re paying suppliers on time without paying early and draining your cash.

4. Review your HST position

In Ontario, the combined GST/HST rate is 13%. If your worldwide taxable revenue passes $30,000 over four consecutive calendar quarters, you’re required to register. Many owners register earlier on purpose so they can claim input tax credits (ITCs) on business purchases.

Each month:

• Confirm HST collected on sales is recorded correctly
• Check that you’re claiming ITCs only on eligible expenses with proper documentation
• Watch for items that are zero-rated or exempt, since they’re treated differently
• Know your filing frequency (monthly, quarterly or annual) and your due date

The CRA explains registration and filing rules on its GST/HST for businesses page. If your filing frequency doesn’t match your volume, or you aren’t sure whether you should be on the Quick Method, it’s worth a conversation before your next return.

5. Confirm payroll and source deductions

If you have employees, you are holding money on the government’s behalf: income tax, CPP and EI. Those remittances are usually due by the 15th of the following month for regular remitters, although your schedule depends on your average monthly withholding amount.

Every month, check that:

• Payroll was calculated correctly, including vacation pay and overtime under the Ontario Employment Standards Act
• Source deductions were remitted on time
• Records of employment (ROEs) were filed for anyone who left
• Your WSIB premiums are current, if your industry requires coverage

The CRA’s payroll information for employers is a good reference, and you can check coverage requirements directly with WSIB Ontario. Late payroll remittances carry some of the steepest penalties out there, so this one deserves a calendar reminder.

6. Collect and file receipts

The CRA expects you to keep supporting documents for six years from the end of the tax year they relate to. That means invoices, receipts, contracts, bank statements and mileage logs.

Go digital. Snap photos of receipts the moment you get them, attach them to the transaction in your software, and you’ll never dig through a shoebox again. For vehicle expenses, keep a running log that shows business versus personal kilometres. The CRA does ask for these during reviews.

7. Track owner compensation and shareholder loans

If you run a corporation, how you pay yourself (salary, dividends or a mix) affects both your personal and corporate tax. It also affects RRSP room and CPP contributions.

Each month, record what you took out and how it was classified. Watch your shareholder loan account closely. If it’s overdrawn at year-end and not repaid in time, the amount can get added to your personal income. That’s an expensive surprise, and an easy one to avoid with a quick monthly look.

8. Review your financial statements

Once everything is reconciled, read your numbers. At minimum, review:

• Profit and loss statement: Are revenues and expenses in line with last month and the same month last year?
• Balance sheet: Do assets, liabilities and equity look reasonable?
• Cash flow: How many weeks of operating expenses do you have in the bank?

You don’t need to be an accountant to spot something odd. If your utilities tripled or your gross margin dropped ten points, ask why.

9. Set aside money for taxes

Nothing hurts quite like a tax bill nobody planned for. Based on your profit, move a percentage into a separate savings account each month to cover corporate income tax, HST owing and, for sole proprietors, personal income tax and CPP.

Ontario corporations that owe more than $3,000 in tax typically need to pay monthly or quarterly instalments. If you’re not sure which applies to you, ask us. Getting it wrong means interest on every missed instalment.

10. Back up your books and close the month

Once everything checks out, lock the period in your accounting software so nobody accidentally changes last month’s numbers. Save a PDF copy of your key reports and back up your file or confirm your cloud software is doing it for you.

A Simple Month-End Schedule That Actually Works

A checklist only helps if you actually use it. Here’s a rhythm that works for most small business owners we work with in Ontario:

• Weekly (30 to 60 minutes): Enter invoices, upload receipts, check bank feeds
• By the 5th: Reconcile all accounts and categorize transactions
• By the 10th: Review receivables, payables and HST
• By the 15th: Confirm payroll remittances, review financial statements and close the month

That’s it. A few small habits beat one giant, painful catch-up session.

Common Bookkeeping Mistakes Ontario Small Businesses Make

After years of helping local business owners, these are the mistakes we see most often:

1. Mixing personal and business spending. Open a dedicated business bank account and credit card. It makes everything easier.
2. Claiming HST on the wrong things. Personal expenses, and some meals and entertainment amounts, are not fully recoverable.
3. Ignoring small deadlines. The CRA doesn’t care that the amount was small. A late filing is a late filing.
4. Skipping reconciliations for “just a couple of months.” Those months pile up fast.
5. Using the wrong software setup. Many owners start with a template found online that doesn’t fit Canadian tax rules. Make sure your software is configured for Ontario HST and Canadian payroll.
6. Waiting until tax season to call an accountant. By then, the best planning opportunities are gone.

DIY, Bookkeeper or Accountant: What’s Right for You?

There’s no single right answer, and it often changes as you grow.

• Doing it yourself can work well when you have few transactions and enjoy staying close to the numbers.
• Hiring a bookkeeper makes sense once you’re spending more than a few hours a week on it, or when payroll and HST get complicated.
• Working with an accountant matters when you need tax planning, corporate filings, owner compensation advice or help during a CRA review.

Many Ontario small businesses use a mix: software and a part-time bookkeeper for the day-to-day, and an accountant for the bigger decisions. If you’d like to see how our team can support you, take a look at the services we offer at TJ Marshall Tax & Accounting or get in touch for a conversation about what would fit your business.

Frequently Asked Questions

How often should an Ontario small business do its bookkeeping?

Transactions should be entered weekly, and accounts should be reconciled and closed monthly. Monthly closing keeps your HST returns, payroll remittances and financial statements accurate and makes year-end filings much faster.

What records do I need to keep for the CRA?

Keep invoices, receipts, bank and credit card statements, payroll records, contracts and mileage logs for six years from the end of the tax year they relate to. Digital copies are accepted as long as they’re clear and complete.

When are HST returns due in Ontario?

It depends on your filing frequency. Monthly and quarterly filers generally must file and pay within one month after the end of the reporting period. Annual filers have different deadlines, and the date also depends on whether you’re a sole proprietor or a corporation.

What’s the HST rate in Ontario?

The HST rate in Ontario is 13%, made up of the 5% federal portion and the 8% provincial portion.

Do I need an accountant if I already use bookkeeping software?

Software records transactions, but it doesn’t give advice. An accountant helps you choose the right structure, plan your owner pay, make the most of deductions and file corporate returns correctly. Most owners find that the savings and peace of mind outweigh the cost.

What happens if I fall behind on bookkeeping?

You can catch up. A professional can reconstruct and clean your books, correct earlier filings where needed and get you back on schedule. The sooner you start, the simpler and cheaper it is.

Final Thoughts

Bookkeeping isn’t glamorous, but it’s the quiet engine behind every healthy small business. A short, repeatable monthly routine keeps you compliant with the CRA, protects your cash flow and gives you the information you need to make confident decisions about hiring, pricing and growth.

If you’d rather hand this off, or you want a second set of eyes on your current process, the team at TJ Marshall Tax & Accounting is here to help Ontario business owners stay organized, compliant and a step ahead. Visit tjm-taxes.com to book a consultation and start the month with a clean slate.

This article is for general information only and isn’t a substitute for professional advice tailored to your situation. Tax rules and deadlines change, so confirm current details with the CRA or a qualified accountant.