What your accountant actually needs each month
Each month, a small company in Poland should deliver a complete pack covering six areas: sales, purchases, bank and cash, payroll/contractors, fixed assets and inventory, plus official correspondence and contracts. In practice this means all sales and cost invoices, bank statements, cash reports, payroll inputs, asset documents, and any letters from tax or social insurance. Include brief notes explaining unusual items, changes in your business, and anything that may affect VAT, income tax or social contributions.
Timely, consistent handover lets your accountant prepare mandatory files, post to KPiR or full ledgers, reconcile VAT/JPK, and keep ZUS and tax payments current. The exact scope depends on your legal form, VAT status and accounting method (e.g., KPiR, lump-sum or full books), so confirm a tailored list. Still, the categories above are universal, and collecting them monthly prevents quarter-end surprises and cash flow shocks from late-assessed liabilities or overlooked input VAT.
Sales: invoices, registers and delivery evidence
Sales documents start with every invoice issued in the month. If you use the National e‑Invoicing System (KSeF), share the KSeF identifiers and any corrections. If you operate outside KSeF, send PDFs with clear numbering and performance dates. Include advance invoices and final settlements, credit notes, and returns. If you issue pro forma documents, mark them clearly as non-tax. For services, provide acceptance protocols or emails confirming completion where applicable.
If you use a fiscal cash register, deliver daily or monthly cash register reports and any periodic summaries printed or exported from the device/software. For e‑commerce, include platform sales reports that show gross, VAT, fees and refunds by day. For intra‑EU supplies or exports, attach proof of shipment or delivery (e.g., courier tracking, CMR, client receipt) to support zero‑rate treatment where applicable. Keep records of promotional discounts and vouchers and how they were redeemed.
Purchases and costs: invoices, imports and special cases
For purchases and costs, provide all supplier invoices and receipts, noting the business purpose when it is not obvious. Add recurring bills such as rent, utilities and software subscriptions. Include employee expense claims with underlying receipts. Flag cases where VAT should be self‑assessed (e.g., certain imported services) so your accountant can post the reverse charge if applicable. Where invoices are missing, add an explanation or substitute document permitted by your policy.
For imports, attach the customs clearance confirmation from your broker or carrier and any VAT settlement documents; for intra‑EU acquisitions, include supplier details and delivery confirmations. Where split payment was used or required, provide the bank confirmation. For foreign‑currency invoices, indicate the transaction date and supply the bank statement or agreed exchange rate basis used for posting. Vehicle‑related costs should be tagged with the vehicle plate and usage policy (business‑only or mixed) to apply correct VAT treatment.
Bank, cash and payment gateways: reconciliation backbone
Banking evidence is the backbone of monthly bookkeeping. Send full bank statements for every account, including foreign‑currency and deposit accounts, ideally as machine‑readable exports alongside PDFs. Cover the entire month and the first day of the next month to catch late postings. Mark unusual transfers (loans, capital injections, owner drawings) with a brief note. Provide loan and leasing contracts, schedules of installments and interest, and any bank fee notices.
Combine bank data with cash and payment gateway evidence. Submit petty cash reports with numbered receipts, POS terminal settlements, and reconciliations from online processors such as PayU, Przelewy24, Stripe, PayPal, Allegro or Amazon. Include payout statements and detailed fee reports so fees are posted net/gross correctly. If you take deposits or gift cards, label them clearly. Your accountant will reconcile gateway balances to bank movements and to issued invoices to catch timing differences.
Payroll, contractors and business travel
If you employ staff, deliver timesheets, overtime approvals, holiday plans, and absence records, plus sick leave confirmations (e‑ZLA numbers are sufficient). Note any benefit changes or bonuses. For new hires or terminations, send signed documents and effective dates. Inform about salary changes before payroll cut‑off. Provide any court orders or garnishments affecting pay. These inputs allow accurate payroll calculation and correct reporting of taxes and social contributions.
For civil‑law contracts (umowa zlecenia, umowa o dzieło) and freelancers, provide signed agreements, statements of work or acceptance protocols, and bills/invoices. Send travel orders and settlements for domestic or foreign trips, including receipts and information needed to apply per diem rules. If private vehicles are used, attach approved mileage logs where relevant. Ensure personal data required for declarations is complete. Flag foreign contractors early, as withholding and reporting obligations can differ.
Assets, inventory and period-end adjustments
Fixed assets and leases need dedicated documentation. For asset purchases, include the supplier invoice and the asset acceptance document, intended use, location, and the planned start of depreciation. Report improvements to existing assets, disposals and write‑offs. Provide lease agreements (operating or finance) with payment schedules and end‑of‑term options. If you maintain an asset register internally, send updates so accounting records stay aligned.
Inventory and period‑end adjustments keep results accurate month to month. Share stock counts for items where quantities matter, including work‑in‑progress notes for ongoing projects. Provide details of prepayments and accruals such as annual insurance, maintenance, or licenses, so costs are recognized in the right periods. Mark customer advances and unearned revenue. List known provisions, warranties or doubtful debts. Add registers of small tools and materials issued to teams.
A simple monthly workflow and a practical checklist
A practical monthly workflow helps everyone meet filing deadlines. Week 1: gather sales and purchase documents, tag special cases (advances, corrections, reverse charge). Week 2: export bank statements, cash reports and gateway reconciliations, and send payroll inputs. Week 3: answer accountant queries, approve draft postings, and escalate missing documents. Throughout: capture KSeF numbers where used, keep proof of delivery for cross‑border sales, and store confirmations of split‑payment or white‑list checks.
Checklist for your handover package: sales invoices and corrections; cash‑register and e‑commerce sales summaries; purchase invoices and employee expenses; bank statements for all accounts; petty cash and POS reports; payment gateway payouts and fee reports; payroll inputs and contracts; asset, lease and inventory documents; travel orders and settlements; loans and capital movements; tax or ZUS correspondence; notes explaining unusual transactions. Send in one zipped folder with dates and clear file names.
Common mistakes to avoid and what to do next
Common mistakes include mixing personal and business payments, omitting FX or secondary bank accounts, skipping cash reports, and ignoring small gateway fees. Others: issuing credit notes but not sending them, losing delivery evidence for intra‑EU sales, forwarding only email text without the invoice attachment, not flagging advances, and providing contractor data too late for payroll. Small gaps snowball into VAT and income tax misstatements, late filings, and avoidable penalties.
Next steps: agree a monthly cut‑off date, a folder structure, and naming rules; designate a document owner; and schedule a quick mid‑month review for cross‑border or asset issues. Verify current rules and system statuses on the Polish Tax Portal, the Social Insurance Institution, the National e‑Invoicing System and the Ministry of Finance. If you want a streamlined setup, Auranik’s 1 Point Business Service Package (/poland/consulting/business-services) can coordinate this flow with your bank, HR and sales tools.
Community content reflects individual experiences and should not be treated as legal, immigration, financial or government advice.
Know someone who may find this guide useful?