Cash flow forecasting with SAP Business One: from reports to a 13-week view

If your books run on SAP Business One — SAP’s ERP system for the mid-market, widely used across Germany, Austria and Switzerland (SAP B1 for short) — you already have the key inputs for a cash flow forecast in-house. They just don’t arrive as a ready-made, week-by-week view. In practice, forecasting with SAP B1 means pulling the right reports out of it and building a rolling 13-week view from them.

This guide walks through what SAP Business One delivers, how to export open items, which free tool fits your export, and how that export becomes a forecast you can rely on.

What SAP Business One gives you toward a forecast — and what it doesn’t

SAP Business One is strong at what it’s built for: ongoing financial bookkeeping, sales and inventory — and it delivers the raw data for liquidity along the way. Three parts of it matter for cash flow:

• Business partner reports (open items): the open receivables and payables per customer and supplier — the incoming and outgoing side of the coming weeks.
• Financial reports (balance sheet, P&L, account statements): the view of profit and account movement — useful, but a profit view, not a cash-timing one.
• The banking module: posted incoming and outgoing payments per bank account, where payments are processed through it — alongside the bank statement in MT940 or CAMT.053 format your bank provides directly.

What SAP Business One doesn’t replace out of the box is a rolling, week-by-week view: expected receipts set against expected payments per week, against the running balance, over a quarter. That’s the view that turns “the report is correct” into “I can see the shortfall before it arrives” — the 13-week cash flow forecast guide explains how that view is built.

Exporting open items from SAP Business One

Every forecast rests on the open items. The open items report for receivables and payables is generated from the business partner reports and exported as a file. A few things matter when you do:

• Due dates. They determine which week a payment is expected in. Without a due date, there’s no week-by-week planning.
• Receivables and payables kept separate. Receivables are the incoming side, payables the outgoing one.
• A consistent, repeating format. If the export looks the same every week, it can be processed without manual rework each time.

For more on the open items list itself — its structure, receivables versus payables, how it’s used — see the open items list guide.

Free template or tool: which fits your export?

The export is done — what’s missing is the grid that turns it into a weekly outlook. Two free routes cover that, and they solve different jobs:

• The free Excel template is a 13-week grid with built-in formulas: you only enter figures in the marked fields, and the calculations are protected against typing errors. The chart shows net cash flow, the cash reserve and the minimum-reserve threshold; the week with the thinnest buffer is marked, and it turns red once the reserve drops below the minimum. A second “Example” sheet shows the structure with fictional numbers, a four-step guide walks through the input, and the sheet is print-ready — landscape, one page with table and chart, for the bank meeting.
• The 13-week forecast generator builds the outlook directly in your browser. You enter two CSV files — open receivables and open payables — plus the account balance; each open invoice lands in its due week, overdue items land in week 1, and items beyond the 13-week horizon are only counted. Recurring payments (payroll, tax, rent, loan repayments) are entered as a weekly amount. The lowest closing balance is the low point; weeks below zero show in red.

For a SAP B1 export, the generator is the shorter path: it reads CSV exports of the open items report from SAP Business One, DATEV and other systems, and all it needs is two columns — one for the due date, one for the amount, in German or English number format. The calculation runs in your browser, nothing is uploaded; only the CSV download itself goes through the form.

Both tools are free and share the same limit: they show a snapshot, not an ongoing plan. The generator is a one-off calculation, and the Excel template is updated by hand — it doesn’t read in reports and doesn’t refresh itself. For a first look at the low point that’s enough. Anyone who rolls the outlook forward every week notices after a few rounds that the work isn’t the calculation — it’s keeping it current.

Four things that trip people up

Four spots regularly go wrong when SAP B1 data is turned into a cash flow forecast:

• A due date is not a payment date. The open items report says when an invoice falls due — not when the customer actually pays. Planning strictly by due date systematically overstates the early weeks. It’s more realistic to factor in each customer’s actual payment behaviour; the gap between the two can be sized with a DSO calculation.
• Early-payment discounts and partial payments distort amounts. An open item sitting at the gross amount may get settled for less once a discount is taken; partial and advance payments show up differently depending on how they’re posted. Both need clarifying once, or every week will look slightly “off” for no obvious reason.
• Recurring payments often aren’t in the open items report. Payroll, tax and loan repayments typically run without an open invoice behind them — they need their own schedule alongside the export. Watch rent and leasing in particular: if they’re posted as a payable invoice, they’re already in the open items report. Only add to the schedule what doesn’t already appear there — otherwise the forecast counts the same payment twice and looks gloomier than it is.
• Several company databases stay separate. If each entity runs its own SAP B1 company database, each open items report is produced separately too. For a consolidated liquidity view across entities, the lists need to be merged — no single export shows the full picture on its own.

From the SAP B1 export to a 13-week view

The weekly plan comes together from the exported open items, the recurring and scheduled payments (payroll, rent, tax, loan repayments) and the current bank balance: each week’s receipts minus payments roll forward against the opening balance, carried across 13 weeks. The lowest point on that curve is the number that matters.

The hard part isn’t building the plan once — it’s the weekly update: pulling a fresh open items report, matching incoming payments, rolling the numbers forward. This is where LiquidityLens comes in: through a mapping assistant with a pre-built SAP B1 template, it reads your business partner reports (open items) directly, forecasts expected receipts from actual payment patterns, and rolls the 13-week view forward with AI — no IT project, built from data your bookkeeping already produces. If you also run DATEV alongside SAP B1, the same path applies through the DATEV cash flow forecast guide — both exports can be consolidated in the same forecast.

Frequently asked questions

The most common questions on cash flow forecasting with SAP Business One are gathered at the end of this page.

Frequently asked questions