Bookkeeping for Small Business in Ontario: A Monthly Checklist That Actually Works

Most small business owners in Ontario know they should be doing bookkeeping. The problem isn't motivation—it's knowing exactly what to do, how often, and what actually matters when CRA comes knocking.

This post gives you a simple, repeatable monthly bookkeeping checklist you can follow whether you use software, spreadsheets, or a shoebox system. The goal: stay organized, stay CRA-ready, and reduce stress at tax time.

Who this checklist is for

This is designed for Ontario small business owners, including:

• Sole proprietors and self-employed individuals
• Incorporated small businesses
• Contractors and freelancers
• Side-hustle earners with business income
• Anyone registered for HST/GST

If you have business income and expenses in Ontario, this applies to you.

Why monthly bookkeeping matters

The biggest bookkeeping mistake I see? Waiting until year-end (or worse, tax season) to organize everything. By then:

• Receipts are lost or faded
• Bank transactions are hard to remember
• Personal and business expenses get mixed up
• You miss deductions you were entitled to
• HST filing becomes a guessing game

Monthly bookkeeping takes 1–2 hours. Year-end catch-up takes days (and costs more if you're paying someone to clean it up).

The monthly bookkeeping checklist

Do these tasks once a month, ideally in the first week of the following month (e.g., do January's bookkeeping in the first week of February).

1. Reconcile your bank and credit card statements

Compare every transaction on your bank and credit card statements against your records. Make sure nothing is missing, duplicated, or miscategorized.

Why it matters: This is the single most important bookkeeping task. If your bank doesn't match your books, everything else is unreliable.

2. Categorize all income and expenses

Every transaction should be assigned to a category: revenue, supplies, advertising, vehicle, meals, etc. Be consistent month to month.

• Use the same categories CRA expects on your tax return
• Don't lump everything into “miscellaneous”
• Separate personal from business spending

3. Collect and organize receipts

For every business expense, you should have a receipt or invoice showing:

• Vendor/supplier name
• Date of purchase
• Amount paid (including HST)
• Description of what was purchased

Digital photos of receipts are fine—CRA accepts digital records. Store them in a folder organized by month.

4. Record any invoices sent and payments received

Track what you billed clients, what's been paid, and what's still outstanding. This helps with cash flow and ensures you're reporting all income accurately.

5. Track HST collected and HST paid

If you're registered for HST/GST, keep a running total of:

• HST you collected on sales
• HST you paid on business expenses (your ITCs)

This makes HST filing straightforward instead of a last-minute scramble.

6. Review mixed-use expenses

If you use your vehicle, phone, or home internet for both personal and business purposes, track the business-use percentage consistently.

• Vehicle: keep a mileage log (even a simple one)
• Phone/internet: estimate and document your business-use percentage
• Home office: calculate based on square footage or rooms used

7. Flag anything unusual

Did you make a large purchase? Receive a payment you're not sure how to categorize? Get a CRA notice? Write it down so you can address it before it becomes a problem.

What tools do you need?

You don't need expensive software. What matters is consistency. Options include:

• Spreadsheet (Excel or Google Sheets) — works well if you're disciplined
• QuickBooks Online — popular for small businesses; automates bank imports
• Wave — free accounting software for basic needs
• Paper ledger — still works if you keep it organized and CRA-ready

The best tool is the one you'll actually use every month.

Common bookkeeping mistakes I see

• Mixing personal and business bank accounts
• Not keeping receipts for cash purchases
• Categorizing everything as “office supplies” or “miscellaneous”
• Forgetting to track HST on expenses (missed ITCs)
• Doing bookkeeping once a year instead of monthly
• Not reconciling bank statements (just trusting the balance)
• Ignoring small transactions that add up

FAQs