Minimum-Viable Bookkeeping for a Solo Business

Book from source documents, not memory

Book from source documents, not memory. Bank feeds speed entry, but receipts, invoices, mileage records, and business-purpose notes are what explain why a transaction belongs on the books.

A 30-minute weekly close is enough for a simple solo business

A 30-minute weekly close is enough for many small solo businesses: import transactions, match receipts, send invoices, review overdue balances, and move the planned tax reserve while the week is still recognizable.

Minimum viable books you can maintain

1. Reconcile bank and card feeds weekly or monthly.
2. Attach source documents to material expenses.
3. Keep invoice numbers and payment status consistent.
4. Track mileage with date and business purpose.
5. Deliver reconciled year-end reports to your CPA or EA.
6. Reconcile processor gross, fees, refunds, and bank deposits before year end.

Bridge gross processor activity to net bank deposits

Track money you collect on behalf of others separately from revenue when appropriate, and learn how processor fees and gross 1099-K reporting affect reconciliation. Net bank deposits can hide gross sales and fees in one line.

Dated mileage records matter when the rate changes midyear

Mileage needs contemporaneous business-purpose records. The IRS changed the business standard mileage rate mid-2026, which is a good example of why bookkeeping should keep dates rather than applying one stale annual number to every trip.

Close the books while mistakes are still recognizable

A minimum viable system should close the books often enough that errors are still recognizable. Once a week, match bank and card transactions, attach missing receipts, send or reconcile invoices, review unpaid balances, log business mileage, and classify any new asset purchase.

Do not wait until tax season to decide what a $437 payment six months earlier represented. A simple cash-basis service business may not need enterprise accounting software, but it does need a complete income record, defensible expense categories, and a reconciliation back to the accounts where money actually moved.

Records that make January boring

Dates matter in 2026 because the IRS changed the optional business mileage rate midyear: 72.5 cents per mile for January through June and 76 cents per mile for July through December. A single annual mileage total with no dates cannot apply those two periods correctly. The same principle applies to changing tax thresholds and processor reporting. At year end, give the preparer more than a shoebox: a reconciled profit-and-loss statement, account summaries, 1099 forms, asset-purchase details, mileage by applicable period, home-office information if relevant, and a short list of unresolved questions. Keep source documents long enough to support the item they prove; the IRS recordkeeping guidance ties retention to the underlying tax purpose rather than one universal receipt rule.

A 30-minute weekly close can prevent the January archaeology problem. First reconcile every bank and card balance to the accounting record. Next review uncategorized transactions, upload missing receipts, and add a one-line business-purpose note where the merchant name is not self-explanatory. Then reconcile invoices: what was billed, what was paid, what remains outstanding, and whether a processor deducted fees before the deposit hit the bank. Finally update mileage and any reimbursable client expenses. Do not let the processor deposit be the revenue number if it is net of fees; record the gross receipt and the fee separately when that reflects the transaction. Likewise, do not double-count revenue merely because a 1099 form later reports a payment already captured in the books. Your ledger should be able to explain the tax forms, not be rebuilt from them.

Create a year-end handoff folder while the year is happening. Include monthly reconciliations, profit-and-loss detail, balance-sheet accounts if relevant, 1099 forms received, W-9s collected from reportable vendors, fixed-asset purchases, vehicle/mileage logs, home-office measurements and costs, health-insurance or retirement records that the preparer requests, and copies of estimated-tax payments. For mixed-use expenses such as phone or internet, document the method used to determine business use rather than choosing a percentage from memory in April. For 2026 mileage, keep the trip date because the federal business mileage rate changed midyear. If a transaction remains uncertain, flag it instead of forcing it into a deduction category. A minimum viable system is successful when another person can trace the number back to the source document without asking you to remember what happened nine months earlier.

Add one monthly control that the weekly close cannot replace: reconcile year-to-date revenue by customer and payment channel. If Client A paid three invoices through ACH and one by card, the customer total in the ledger should equal the four invoices even though the bank shows different deposit descriptions and processor fees. Compare that customer view with any 1099 forms only after year end. Also scan the balance sheet for negative cash, old receivables, unexplained owner balances, or processor clearing amounts that never settled. Those are often bookkeeping-process errors rather than tax problems. Fix them while the source documents are still easy to retrieve. A solo business does not need dozens of reports; it needs a repeatable path from invoice to payment to bank to tax return.

Bookkeeping questions worth answering early