A sawmill's books have one quirk that generic small-business templates ignore: inventory arrives as standing timber and leaves as boards, chips, and sawdust. In between it changes shape, weight, and value, sometimes several times in a week. Double-entry bookkeeping handles that fine, but only if the chart of accounts is built for a mill rather than a retail shop.

Why double entry earns its keep

Single-entry records tell you what's in the bank. Double entry tells you why it changed. Every transaction hits at least two accounts, so the books stay in balance and you can trace a dollar from the log yard to the lumber stack to the deposit slip. For a mill, that traceability is the whole point. When you spend $15,000 on a load of sawlogs and sell the lumber six weeks later, you want to know what that load actually earned.

If you're moving up from a shoebox of receipts, start with clean cash records, then layer in inventory and accrual accounts as you get comfortable. Cash-basis bookkeeping is a fine beginning; it just can't tell you what your inventory is worth on a given day.

The core chart of accounts for a small mill

You don't need two hundred accounts. You need enough detail to see where logs turn into money. Number them in blocks of 100 so there's room to grow. A solid starting set:

• Cash – Operating (1000) and Cash – Reserve (1010)
• Accounts Receivable (1100) for customers who take lumber on terms
• Log Inventory (1200) for sawlogs and timber you own but haven't milled
• Lumber Inventory (1210) for milled stock, green or dried
• By-Product Inventory (1220) for chips, sawdust, and slabs if you sell them
• Supplies & Blades (1300) for consumables you'd rather track than expense outright
• Equipment – Sawmill (1500) and Accumulated Depreciation (1510)
• Accounts Payable (2000), Payroll Liabilities (2100), Sales Tax Payable (2200), Equipment Loans (2300)
• Owner's Capital (3000) and Owner's Draws (3100)
• Lumber Sales (4000), By-Product Sales (4010), Custom Sawing Income (4020)
• Cost of Sales (5000 series): log usage, direct saw crew labor, mill consumables
• Operating Expenses (6000 series): repairs, fuel, insurance, depreciation, office payroll, professional fees

Two decisions matter more than the rest. First, do you keep one inventory account or split logs from lumber? Splitting them lets you watch milling margin separately from log cost, which is usually the number that tells you whether the mill is healthy. Second, are saw crew wages a cost of sales or an operating expense? For a mill, direct labor that touches the product belongs in cost of sales. Office and sales payroll does not.

Recording a first month, line by line

Here's how that first month looks once the accounts exist. Amounts are illustrative.

1. Owner funds the business with $40,000. Debit Cash $40,000; credit Owner's Capital $40,000.
2. Buy a load of logs for $15,000 on 30-day terms. Debit Log Inventory $15,000; credit Accounts Payable $15,000.
3. Run payroll for the saw crew, $6,000. Debit Direct Labor (cost of sales) $6,000; credit Payroll Liabilities and Cash.
4. Mill the logs into lumber. Move the cost forward. Debit Lumber Inventory for the log value plus the labor used, and credit Log Inventory and Direct Labor for the same amounts. You've converted one asset into another and added value with labor.
5. Sell lumber for $22,000, half cash and half on account. Debit Cash $11,000 and Accounts Receivable $11,000; credit Lumber Sales $22,000. Then record the cost side: debit Cost of Sales and credit Lumber Inventory for what those boards cost to produce.
6. Buy blades and filters for $1,200 cash. Debit Supplies & Blades $1,200; credit Cash $1,200, then expense them as they're used.
7. Make the equipment payment of $1,500. Debit the loan principal, debit Interest Expense, credit Cash. Only the interest portion is an expense.
8. Record depreciation on the mill and support equipment. Debit Depreciation Expense; credit Accumulated Depreciation.

If step four feels like too much at first, skip it and adjust inventory once a month from a physical tally instead. That's less precise, but it beats guessing, and plenty of small mills run that way until volume makes the detail worth the effort.

Month-end: three checks that catch most errors

• The trial balance balances. Total debits should equal total credits. If they don't, look for a transaction entered only once, or an inventory transfer posted to just one side.
• Lumber inventory ties to the tally. Compare book value to your board-foot count at period end. A gap usually means a sale was recorded without its matching cost entry, or shrinkage never written off.
• Log inventory ties to scale tickets. Compare what you paid for against what you've milled. Unrecorded log usage quietly inflates profit and makes the yard count look wrong.

Keep the setup boring and it keeps working

Resist adding a new account every time something unusual happens. Group small items under Supplies or Repairs, and split them out later if they grow. Post transactions weekly so the log yard and the ledger don't drift apart. Reconcile the bank account every month, no exceptions. When you add a kiln, a planer, or a second crew, revisit the chart then, not in the middle of a busy season. Rules for valuing inventory, taxing timber sales, and depreciating equipment vary by state and by how your business is organized, so have a CPA who knows the wood products industry review your setup before the first tax filing.

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