Spreadsheet Lab - Browser Spreadsheet with Formula Builder
Full-featured browser spreadsheet with 37 Excel formulas, visual formula builder, multi-sheet workbooks, XLSX import/export, formatting, and freeze panes. No signup, no cloud.
Runs in your browser. No data leaves your device.
Frequently Asked Questions
How does Spreadsheet Lab work?
The formula engine uses a recursive-descent parser with a safe arithmetic evaluator (no eval/Function) to tokenize and evaluate expressions. Cell references are resolved recursively through a visited-set that detects circular dependencies. The engine supports 37 functions, cross-sheet references via a Sheet!Cell lookup, and range expansion. The grid uses virtualized row rendering for performance, and import/export lazy-loads SheetJS on demand.
What formulas and functions does this spreadsheet support?
It includes 37 Excel-compatible functions across six categories. Math and statistics: SUM, AVERAGE, MEDIAN, MIN, MAX, COUNT, COUNTIF, SUMIF, SUMPRODUCT, ABS, ROUND, MOD, INT, SQRT, and POWER. Text: CONCAT, UPPER, LOWER, TRIM, LEN, LEFT, RIGHT, MID, SUBSTITUTE, and TEXT. Logic: IF with six comparison operators. Dates: TODAY, NOW, DATE, YEAR, MONTH, and DAY. Lookups: VLOOKUP, HLOOKUP, INDEX, and MATCH. Links: HYPERLINK. You can also write arithmetic expressions, use cell references like A1:B10, and reference other sheets with Sheet2!A1 syntax.
Can I open and save Excel files?
Yes. You can import XLSX, XLS, CSV, TSV, and ODS files, including workbooks with multiple sheets. Export your work as an XLSX workbook (preserves all sheets) or as a CSV file for the active sheet. This makes it easy to move data between this tool and Excel, Google Sheets, or LibreOffice.
Is this a free alternative to Google Sheets that works without an account?
Yes. There is no sign-up, no login, and no cloud storage. The spreadsheet loads instantly in your browser and all your data is saved locally on your device. It supports multi-sheet workbooks, cell formatting, formulas, and import/export -- the core features most people need from a spreadsheet.
Is my data private and secure?
Yes. Your spreadsheet data is stored locally and never uploaded to any server. Use the XLSX export to save important work.
What editing features does it have beyond formulas?
Cell formatting with bold text, 16 background colors, 13 text colors, and left/center/right alignment. Number formats including currency, percent, decimal, and date display. Text wrapping with auto-adjusting row heights. Freeze rows and columns so headers stay visible while scrolling. Find and replace across formulas and values. Undo and redo with 50 levels of history. Drag-to-fill that auto-extends number sequences and month names. Right-click context menu for inserting, deleting, and sorting rows and columns.
How large can the spreadsheet be?
The default grid is 100 rows by 26 columns (A through Z), but you can expand it up to 10,000 rows and 702 columns (A through ZZ). Virtual scrolling keeps the interface fast even with large grids. The spreadsheet also supports multiple sheet tabs, so you can organize data across separate sheets within the same workbook.