How to Edit an Excel Spreadsheet Online

Editing a spreadsheet online only makes sense if the editor actually understands formulas, multiple sheets, and formatting — not just a grid you can type into. Here's what that looks like in practice.

Opening an Excel or CSV file

JTDesigner's Spreadsheet Studio imports .xlsx workbooks — preserving multiple sheets, formulas, styling, merged cells and freeze panes where supported — as well as plain CSV files. CSV import keeps a formula-interpretation toggle off by default, as a safety measure against unexpectedly executing formula-like text from an untrusted file.

Formulas that actually work

Spreadsheet Studio runs its own formula engine with roughly 80 functions, covering:

• Math (SUM, ROUND, POWER, CEILING, and more)
• Statistics (AVERAGE, MEDIAN, STDEV, SUMIF/S, COUNTIF/S)
• Logical (IF, IFS, AND/OR/NOT, IFERROR)
• Lookup (VLOOKUP, HLOOKUP, XLOOKUP, INDEX/MATCH)
• Text (LEFT/RIGHT/MID, TEXTJOIN, SUBSTITUTE)
• Date & time (DATE, EDATE, EOMONTH, WEEKDAY)

Recalculation happens automatically as you edit.

Formatting and conditional formatting

You can format fonts, colors, borders, fills, alignment and number formats (currency, percent, scientific, date, custom), plus set conditional formatting rules, color scales and data bars to visually highlight patterns. Freeze panes (top row, first column, or a custom range) keep headers visible while scrolling.

Charts and named ranges

Insert charts — column, bar, line, area, pie, donut or scatter — bound to a data range, and define named ranges scoped to a single sheet or the whole workbook so formulas can reference a range by name.

Exporting

Export your workbook back to .xlsx, to CSV (a single sheet or all sheets), or save it as JTDesigner's portable JTProject format to keep editing it later.

Where JTDesigner fits

Spreadsheet Studio is one of JTDesigner's seven browser-based Studios, all sharing the same local-first, portable-project approach.