Plenty of small business accounting files have no numbers in the chart of accounts at all. QuickBooks Online ships with account numbers turned off, so the accounts sit in alphabetical order inside each type, and the balance sheet reads in whatever sequence the names happened to fall in. Advertising above Bank fees, Rent below Payroll.
That works until the chart gets long enough that you stop being able to find things in it, or until something outside QuickBooks has to line up with it. Then you want numbers, and the numbers you pick are hard to change later, so they're worth picking on purpose.
What the number is actually for
An account number gives the account an identity separate from its name. Rename "Contractors" to "Outside services" and 6180 is still 6180, so a report built against it keeps working and last year's figure is still comparable.
It also gives the ledger an order that isn't alphabetical. Cash before receivables before fixed assets is a deliberate sequence, and the only way to hold it is to number it. In QuickBooks Online the number shows up in reports and transactions once you turn on the "Show account numbers" option, which is what makes the ordering visible to whoever reads the financials.
The third thing it gives you is a gap. When you can see that nothing sits between 6100 and 6200, you can see where a new expense account belongs before you create it. Without numbers, every new account is filed by first letter and the structure erodes one addition at a time.
The blocks
Four digits, with the first digit carrying the account's category. It's the convention accounting systems, templates and accountants already work in, so using it means nobody has to learn your file.
| Range | Holds |
|---|---|
| 1000 to 1999 | Assets |
| 2000 to 2999 | Liabilities |
| 3000 to 3999 | Equity |
| 4000 to 4999 | Revenue |
| 5000 to 5999 | Cost of revenue |
| 6000 to 6999 | Operating expenses |
| 7000 to 7999 | Other income |
| 8000 to 8999 | Other expense |
| 9000 to 9999 | Income tax, and anything provisional |
The order matters more than the specific digits, because it's the order the financial statements come out in. Assets, liabilities and equity build the balance sheet from top to bottom. Revenue through other expense build the income statement the same way. A file numbered this way produces statements that read correctly without anyone sorting anything.
Inside each block, use sub-blocks of a hundred:
| Range | Holds |
|---|---|
| 1000 to 1099 | Cash and bank accounts |
| 1100 to 1199 | Accounts receivable |
| 1200 to 1299 | Other current assets, prepaid expenses, inventory |
| 1500 to 1599 | Fixed assets |
| 1600 to 1699 | Accumulated depreciation |
| 2000 to 2099 | Accounts payable |
| 2100 to 2199 | Credit cards |
| 2200 to 2299 | Accrued liabilities and payroll liabilities |
| 2300 to 2399 | Sales tax payable |
| 2500 to 2599 | Loans and long-term debt |
Two details in there are worth naming. Accumulated depreciation gets its own sub-block rather than living next to the asset it offsets, so the fixed asset register stays readable as a list of things you own. And sales tax payable sits away from the other accruals because it's money you're holding for a state rather than an expense you owe, and you will want it isolated when you file.
Leave room
Tight spacing is the part that gets regretted. Number the first five expense accounts 6001 through 6005 and the sixth one, which belongs alphabetically and logically between the second and third, has nowhere to go.
Number in tens. 6010, 6020, 6030. That leaves nine slots between any two accounts, which is enough for a decade of a small business, and it costs nothing today.
| Number | Account |
|---|---|
| 6010 | Advertising and marketing |
| 6020 | Bank and merchant fees |
| 6030 | Contractors |
| 6040 | Dues and subscriptions |
| 6050 | Insurance |
| 6060 | Meals |
| 6070 | Office supplies |
| 6080 | Professional fees |
| 6100 | Payroll wages |
| 6110 | Payroll taxes |
| 6120 | Employee benefits |
| 6200 | Rent |
| 6210 | Utilities |
| 6300 | Software |
| 6400 | Travel |
Payroll starting at 6100 rather than 6090 is the same idea one level up. Related accounts that will grow into a group get a hundred-block, not the next available ten.
What does not belong in the number
The tempting move, once you have a numbering system, is to encode more into it. Department in the fifth digit. Location in the first two. Product line somewhere.
Resist that, because your accounting system already has fields for those and they behave better. QuickBooks calls them classes and locations, Xero calls them tracking categories, and the difference is dimensional. A class is a value you attach to a transaction, so adding a department means adding one entry to a dropdown. A department in the account number means the chart of accounts multiplies: every expense account has to exist once per department, and a new department is a renumbering project across the whole file.
The test is whether you want to see the accounts side by side. If you want rent for the Denver office and rent for the Austin office on the same line of a report most of the time, and split only sometimes, that's one Rent account with a location on each transaction. If they're genuinely different kinds of cost that you never want summed, they're different accounts.
Class tracking has a related requirement that catches people out: it only works if every transaction carries one. A class field that's populated on 70% of the ledger produces a report where the unclassified column is the interesting one, and you're back to guessing.
Turning numbers on in QuickBooks
In QuickBooks Online the feature is off until you switch it on. Go to Settings, then Account and settings, then the Advanced tab, then Edit in the Chart of accounts section. Turn on "Enable account numbers", and turn on "Show account numbers" too if you want the numbers to appear in reports and transactions, which is usually the point. Save, then Done.
Filling in the numbers one account at a time through the edit screen is slow. On the Chart of accounts page there's a Batch edit control above the Action column, which gives you a Number column down the whole list and one Save at the end. A fifty account chart takes a few minutes that way.
QuickBooks Desktop keeps the same setting somewhere else. On Windows it's Edit, then Preferences, then Accounting, then the Company Preferences tab, then the "Use account numbers" checkbox. On Mac it's under QuickBooks, then Preferences, then Transactions.
One thing QuickBooks won't do is number the accounts for you. Intuit's own documentation says it plainly: QuickBooks doesn't assign account numbers to accounts you add, you assign them when you create or edit your own accounts. So switching the feature on gives you an empty Number column, and the structure is still a decision you have to make.
Treat the numbers as unique. Two accounts sharing one defeats the only job the number has.
Renumbering a file that already has history
Changing an account's number is safe in the accounting sense. The number belongs to the account, not to each transaction, so editing it updates the account's identity everywhere including in prior periods. Last year's balance sheet will show the new number the next time you run it, and no balance moves.
What breaks is outside the file. A tax preparer's workpapers that reference account numbers, a mapping table in an integration that posts to 6300 by number, a saved export somebody's forecast reads, a Google Sheet with a lookup on the number column. None of those find out that 6300 became 6310.
So do a renumbering in one pass rather than a few accounts at a time, tell whoever consumes the file, and keep a before-and-after list of the changes. The list is the thing people ask for later, and reconstructing it after the fact means reading the audit log account by account.
If the file is under audit or review for a period, leave that period's structure alone until the work is signed off. An auditor holding a trial balance keyed to the old numbers has to redo their tie-outs, and that time gets billed to you.
When to add an account and when not to
A chart of accounts grows because adding an account is easier than deciding where a transaction belongs. Two hundred accounts, forty of them used twice, is the end state.
Before adding one, check whether you want to see it as a line on the income statement. If the answer is that you'd only ever look at it split by vendor, or by customer, or by project, then the vendor, customer or class field already answers the question and the new account just makes the statement longer.
Software is the usual example. Twelve accounts for twelve tools tells you nothing a vendor report doesn't tell you better, and it costs you a readable expense section. One Software account, with the vendor on each transaction, answers both questions.
The other half of the same discipline is deleting. An account you'll never use again should be made inactive so it stops appearing in the dropdown, though a balance sitting in it has to go somewhere identified first. Never merge or retire an account inside a period somebody has already relied on without deciding, explicitly, where its balance lands.
A chart you can actually read
The point of all of this is a set of financials somebody can scan in thirty seconds. Numbered blocks that match the statement order, ten-wide gaps so the structure survives contact with next year, dimensions in the class field where they belong, and a chart short enough that every account on it means something.
If your current file has no numbers and forty accounts, adding numbers is an afternoon and it's worth doing before the chart gets to a hundred. If it has no numbers and two hundred accounts, the numbering isn't the first job. Working out which of the two hundred you actually use is.