WB-EasyCalc online: a free web alternative to the Excel water balance

If you have done a water balance in the last twenty years there is a good chance you used WB-EasyCalc, the free Excel workbook first released by Roland Liemberger in 2006 and later extended with a carbon balance as WCB-EasyCalc by David Pearson, Stuart Hamilton and Bambos Charalambous. It has been translated into more than thirty languages and is cited in regulatory frameworks from Greece to Indonesia.

What EasyCalc does

It implements the IWA standard water balance with 95% confidence limits on every input, calculates the UARL and ILI, places the result on the World Bank Institute matrices, values the components at tariff and marginal cost, and — in the WCB version — converts every component to tonnes of CO₂ using treatment-process factors. The spreadsheet is password-protected, which keeps the formulas intact but makes it hard to extend or audit.

What a web implementation adds

• Guidance at the point of entry: each input explains what it is, where to find it, and what a defensible uncertainty looks like — with an assistant that suggests localised values when you have none.
• A live balance that updates as you type, so a data-entry error shows up immediately instead of on the results sheet.
• Saved versions organised by client, country, region and DMA, so the annual balance is a trend rather than a folder of workbooks.
• A branded PDF report and an Excel export that opens anywhere.
• Import of existing WB-EasyCalc and WCB-EasyCalc files, so nothing has to be re-typed.

Same numbers

The calculation engine reproduces EasyCalc's formulas line by line — the uncertainty propagation, the meter-error volume V/(1−u)−V, the connection-weighted pressure, the supply-time correction, the band thresholds and the carbon factors — and corrects one minor error in the source's carbon uncertainty for unbilled metered consumption. The methodology page publishes every formula so the results can be audited.

When to keep using the spreadsheet

If your regulator requires the EasyCalc file itself, keep submitting it: build the balance here, export to Excel, and transfer the inputs. If you work offline in the field, the spreadsheet still wins. For everything else — especially if you produce balances for multiple clients or zones — the web tool is faster and harder to get wrong.