Live Formula Recalculation — How Unsheet Keeps Your Data Alive

Unsheet doesn't just display your spreadsheet data — it runs a full formula engine in your browser.

When your app loads, the raw 2D data array (including formula strings like =B2*C2) is loaded into HyperFormula, a headless spreadsheet engine that implements the full OpenDocument standard.

HyperFormula builds a dependency graph of all your formulas. When you change any value, it identifies every cell that depends on the changed cell and recalculates them in the correct order — just like Excel does.

In the table component, every numeric and currency column is rendered as an editable input field:

1. Click on any number in the table
2. Type a new value
3. Click away or press Tab to commit the change
4. All dependent formulas recalculate instantly

For example, if your spreadsheet has Total = Quantity × Price, changing the Quantity will instantly update the Total column, the Grand Total metric card, and any charts that reference those values.

The real power of Unsheet's formula engine is cascading recalculation. Consider this scenario:

• Cell D2 = =B2*C2 (line item total)
• Cell D10 = =SUM(D2:D9) (grand total)
• A metric card displays the value of D10
• A chart plots column D values

When you change B2 (quantity), here's what happens in milliseconds:

1. D2 recalculates (new line total)
2. D10 recalculates (new grand total)
3. The metric card updates to show the new grand total
4. The chart re-renders with the new data point

All of this happens client-side, with zero server round-trips.

If Unsheet detects categorical columns in your data (like Region, Status, or Category), it may generate a dropdown component. Selecting a value from the dropdown writes it to a specific cell in the HyperFormula engine, which can trigger formula recalculation throughout the sheet.

This is perfect for scenario modelling: "What happens to revenue if I switch from North to South region?"