A period you can still edit is not closed
Locking a period is what makes a reported number mean something. Everything found afterwards is a correction posted forward — visible, dated, and leaving the original in place.
The Comma team3 min read
Notes on real books and AI
Double-entry bookkeeping, audit-ready business records, and running your books with an AI assistant.
Inventory is an asset until it sells, and then it is a cost
Buying stock does not reduce profit. Selling it does. Getting that timing wrong is why a busy month can look unprofitable and a quiet one can look excellent.
2 min read
The Canadian filing calendar a small company actually has
Source deductions, sales tax, information slips and the corporate return run on four different clocks set by four different rules. Here is the shape of the year.
3 min read
Accruals and prepayments, and the reversal that stops the double count
Adjusting entries are where a cash-shaped ledger becomes an accrual one. They are also where the same cost gets counted twice, because the adjustment was never reversed.
2 min read
When the control account stops agreeing with the subledger
Accounts receivable should always equal the sum of unpaid invoices. When it does not, someone posted a journal straight to the control account — and that is worth finding.
3 min read
Your payroll liability accounts should have a shape
Each payroll liability has a predictable rhythm. A balance that does not fit the rhythm is the cheapest error you will ever find — and the one most often found by the CRA instead.
3 min read
Capitalise or expense, and why your books and your tax return disagree
Buying equipment creates two separate calculations that will never match — book depreciation and capital cost allowance. Keeping them separate is the whole job.
3 min read
Three statements, three different questions
The P&L, the balance sheet and the cash flow statement are not three views of the same number. Each answers a question the others cannot, which is why a profitable business can run out of money.
3 min read
Procure to pay — the controls that stop you paying twice
The purchasing chain is where small companies lose the most money to simple error: duplicate payments, prices nobody agreed to, and suppliers who were never really suppliers.
3 min read
What your books have to prove, and for how long
An audit trail is not paperwork. It is the difference between a number you can defend and a number you are asserting — and the retention rules run longer than most people assume.
3 min read
Order to cash — what happens between the sale and the money
Invoicing is one step in a chain that ends with cash and a closed receivable. The steps in between are where revenue quietly goes missing.
3 min read
Segregation of duties when there are three of you
The textbook control assumes enough people to separate every function. Small companies cannot. Here is what to separate first, and what to substitute when you cannot separate anything.
3 min read
The accounting cycle, and why the order is not negotiable
Every set of books runs the same loop from transaction to statement. Knowing the sequence is what turns bookkeeping from a pile of tasks into a process you can hand to someone else.
3 min read