Drag & drop your files here
Max 20 files • Max file size: 100MB
Accepted formats: .xlsx, .xlsm, .xls, .xlsb, .ods
Multi-level optimization for smaller spreadsheet files
Excel file compression reduces spreadsheet size through multi-level optimization: embedded image compression (screenshots, chart exports), XML structure minification, blank row/column removal, and ZIP container recompression. Unlike Microsoft's manual methods (documentation ranks #1 but requires multiple steps: compress images within Excel, delete blank rows individually, save as binary format), this tool automates the entire process in your browser using JSZip v3.10.1 + browser-image-compression v2.0.2.
XLSX files are ZIP archives containing XML files (sheets, styles, formulas) and an xl/media/ folder with embedded images. Tool extracts the archive, optimizes images (JPEG quality adjustment, PNG→JPEG conversion for photos), minifies XML structure (removes whitespace between tags, 5-15% savings), removes calculation chain cache (xl/calcChain.xml), strips blank rows extending sheet range, and repacks with DEFLATE level 9 compression. Legacy formats (.xls binary, .xlsb binary workbook) converted to .xlsx using SheetJS first, then optimized.
Data, formulas, and calculations ALWAYS preserved perfectly regardless of compression level. Only embedded images may have quality reduction (configurable via presets). Excel calculations, pivot tables, charts, conditional formatting all work identically after compression. Result: 40-80% smaller Excel files with complete data integrity.
Automated multi-level optimization—faster than Microsoft's manual methods
Drag and drop Excel files onto the page, or click "Choose Excel Files" to browse. Up to 20 spreadsheets at once (100MB maximum per file). Accepts XLSX, XLSM, XLS (Excel 97-2003), XLSB (binary workbook), ODS (OpenOffice). Legacy formats (.xls, .xlsb) automatically converted to .xlsx using SheetJS, then optimized. Files never leave your browser—processed locally.
Four quality presets: High Quality (92% image quality, 2400px, 30-50% reduction, chart-quality priority), Balanced (80%, 1920px, 50-70%, recommended for most uses), Email Ready (70%, 1200px, 60-75%, targets <20mb (55%, 70-80%, 800px, aggressive attachments, balanced balance—significant best cache charts cleanup). comments embedded files, for hidden loss maximum metadata), noticeable on p pivot preset provides quality reduction removes screenshots.< sheets size smallest without>
Processing takes 3-10 seconds per spreadsheet depending on size, number of sheets, and embedded images. Download individually or as ZIP for batches. Powered by JSZip v3.10.1 (ZIP extraction/repacking) + browser-image-compression v2.0.2 (image optimization) + SheetJS (legacy conversion). Sequential processing (one file at a time). "Never return larger" guarantee—if compression produces bigger file, original kept. Legacy conversions: report.xls → report.xlsx, budget.xlsb → budget.xlsx (filenames change, VBA macros lost).
Understanding what makes spreadsheets bloat
Biggest factor: Screenshots, chart exports (rendered as images), logos uncompressed. Single uncompressed screenshot: 2-5 MB.
Example: Spreadsheet data (5000 rows × 50 columns with formulas): 500 KB-2 MB. 8 screenshots from Snipping Tool (full HD): 24-40 MB uncompressed. Total: 24-42 MB (95% is images).
Excel stores "used range" (top-left to bottom-right). Accidentally clicking cell Z10000 makes Excel store 10,000 blank rows in XML.
Example: Actual data: 100 rows × 10 columns. Accidental click: cell AA5000. Excel stores: 5000 rows × 27 columns = 135,000 blank cells (adds 500KB-2MB). Microsoft manual method: delete blank rows manually (tedious). This tool removes automatically.
Excel workbooks accumulate hidden sheets: old data, templates, scratch calculations, backup tabs. Each sheet adds to file size even if hidden.
Size impact: Each hidden sheet with 1000 rows = 50-200 KB. 10 hidden sheets = 500KB-2MB bloat. Email Ready preset removes automatically.
xl/calcChain.xml stores formula calculation order (50KB-500KB). Excel rebuilds this on open anyway—removing it is safe.
Zero functional impact. Formulas work identically. First open might be 0.1-0.5 seconds slower (negligible). This tool removes automatically for all presets.
Complex conditional formatting rules (color scales, data bars, icon sets on thousands of cells) stored as XML. Unused styles accumulate over time.
Size impact: 100KB-1MB for heavily-formatted spreadsheets (dashboards, reports with extensive formatting). XML stores every rule and its conditions.
Same as Word—prioritizes compatibility and user control. Excel has no built-in "Compress File" option. Users must manually: (1) Select each image → Picture Format → Compress Pictures, (2) Find & Select → Go To Special → Blanks → Delete (tedious for thousands of blank rows), (3) Save as Binary Workbook (.xlsb) for 60-70% reduction but loses some compatibility.
This tool automates ALL steps in seconds: extracts XLSX ZIP archive, compresses all images at once, removes blank rows programmatically, minifies XML structure, strips unnecessary files, repacks with maximum ZIP compression.
Five techniques always applied—safe, never affect functionality
XLSX files contain XML for each sheet, styles, formulas. XML includes human-readable whitespace (newlines, indentation) unnecessary for Excel.
What's removed: Whitespace between tags (> < becomes ><), newlines, XML comments. Size impact: 10MB spreadsheet with 50 sheets saves 800KB-1.5MB from XML minification alone. Formula-heavy sheets benefit most.
xl/calcChain.xml stores formula calculation order. Excel rebuilds automatically when file opens (0.1-0.5 seconds, negligible).
Removing saves space with zero functional impact—formulas work identically. Always safe. Complex spreadsheets with hundreds of formulas: 200-500KB saved.
Excel stores "used range" (top-left to bottom-right). Accidental clicks far from data make Excel store thousands of blank rows.
Example: 100 rows of data with accidental cell AA5000 clicked = Excel stores 5000 rows × 27 columns. Removal saves 500KB-2MB. Tool detects and removes automatically.
Files always safe to remove: Printer settings (xl/printerSettings/ - user sets when printing), volatile dependencies (recalculated automatically), control properties (ActiveX controls, rare), custom XML (bloat from add-ins).
Size impact: 50-200KB typical, up to 1MB for corporate templates with extensive print settings. Zero functional impact.
xl/sharedStrings.xml stores deduplicated text (cell text stored once, referenced by ID). Minifies by removing whitespace between string entries.
Size impact: 50-300KB for text-heavy spreadsheets (reports, dashboards with labels). Sales reports with 5000 rows might save 200-400KB.
All optimizations preserve data, formulas, calculations, formatting perfectly. Only images may have quality reduction (configurable). Excel calculations, pivot tables, charts, conditional formatting all work identically after compression.
Choose your quality vs file size trade-off
Settings: 92% image quality, 2400px max dimension, keeps all content (revision history, comments, metadata, pivot cache, hidden sheets).
When to use: Professional reports for clients, data with high-quality charts, archival copies. Data preservation: All formulas, calculations, formatting perfectly preserved.
Settings: 80% image quality, 1920px max dimension (HD), keeps metadata/comments, removes blank rows automatically.
Sweet spot: Best balance—significant size reduction without noticeable quality loss on embedded charts/screenshots. General purpose, internal reports, data sharing, 90% of use cases.
Settings: 70% image quality, 1200px max dimension, removes bloat (blank rows, comments, metadata, printer settings, pivot cache, hidden sheets).
Target: Under 10-20MB for reliable email delivery (Gmail 25MB limit). Good for screens, minor image compression artifacts. Privacy benefit: Metadata removed (author name, company, timestamps).
Settings: 55% image quality, 800px max dimension, aggressive cleanup (all optional data removed, pivot cache cleared, hidden sheets deleted).
Warning: Acceptable for data review, visible image artifacts on charts/screenshots. Data guarantee: Formulas and calculations perfect. Not suitable for professional presentations with high-quality charts.
100% browser-based with JSZip + browser-image-compression + SheetJS
100% browser-based Excel compression using JSZip v3.10.1 (ZIP extraction/repacking), browser-image-compression v2.0.2 (image optimization), and SheetJS (legacy .xls/.xlsb conversion) libraries loaded from CDN, cached locally. Excel files never leave your device—no upload to servers, no storage, no exposure. XLSX files extracted as ZIP archives locally, optimized in memory, repacked locally.
Budgets, forecasts, P&L stays private
Customer lists, revenue, pipeline never exposed
Salaries, employee records protected
Formulas, business models secured
Confidential projects never stored
Tax calculations, planning secured
No POST endpoint in codebase. Files stay in browser memory only. JSZip extracts XLSX locally, optimizes, repacks. SheetJS (legacy conversion) runs client-side. GDPR compliant by design—no data collection possible. Works offline after libraries load (cached in browser). Email Ready/Maximum presets strip metadata (author name, company, timestamps) for additional privacy.
Everything about compressing Excel files
Add your Excel file (drag-drop or click "Choose Excel Files"), select Balanced preset for 50-70% reduction with excellent quality, then click Compress. Processing takes 3-10 seconds per spreadsheet depending on size and embedded images. Works entirely in your browser using JSZip + browser-image-compression—files never uploaded. Data and formulas always preserved perfectly.
Compress embedded images (the #1 cause—95% of file size in image-heavy spreadsheets), remove blank rows/columns (500KB-2MB saved from accidental clicks), minify XML structure (5-15% savings), remove calcChain.xml (50-500KB), delete hidden sheets, clear pivot cache. This tool handles all automatically. Balanced preset: 50-70% reduction while maintaining data integrity.
NO. Data, formulas, and calculations ALWAYS preserved perfectly regardless of compression level. Only embedded images (screenshots, charts exported as images) may have quality reduction depending on preset. Excel calculations, pivot tables, conditional formatting all work identically after compression. Text and numbers completely untouched. This is CRITICAL for Excel where data integrity is non-negotiable.
Uncompressed embedded images/screenshots (single screenshot 2-5 MB, data only 500KB-2MB = images are 95%), blank rows extending range (accidental cell AA5000 click stores 135,000 blank cells = 500KB-2MB), hidden sheets, calculation chain cache (50-500KB), conditional formatting (100KB-1MB on heavily-formatted sheets), pivot cache. Excel stores more than you see.
Excel has "Compress Pictures" for images within document (select image → Picture Format → Compress Pictures) but NO built-in FILE compression. Compress Pictures requires selecting each image manually (tedious for 10+ images). This tool compresses entire Excel FILE automatically—all images at once, plus blank row removal, XML minification, calcChain removal, unnecessary file cleanup.
Yes. XLSX files are already ZIP-compressed internally but can be further compressed by optimizing contents: compress embedded images, minify XML, remove blank rows, delete unnecessary files. Typical reduction: 40-80% depending on content. Image-heavy spreadsheets (dashboards with charts/screenshots): 60-80%. Text/number-heavy (financial reports): 30-50%. Formulas and data always preserved perfectly.
Use Email Ready preset—specifically designed for email attachments. Targets under 10-20MB for reliable delivery (Gmail 25MB limit, Outlook 20MB, corporate often 10MB). 70% image quality (good for screen viewing), removes bloat (blank rows, comments, metadata, pivot cache, hidden sheets). If still too large after compression, share via OneDrive/Google Sheets link.
Excel built-in: Select picture → Picture Format → Compress Pictures → Choose quality (repeat for each image manually). OR use this tool: automatically compresses ALL images in entire spreadsheet in one click—faster, easier. Our tool also includes blank row removal, XML minification, and unnecessary file cleanup that Excel's built-in feature doesn't do.
Depends on preset. High Quality: nothing removed (only images compressed). Balanced: blank rows/columns, calcChain.xml (safe, Excel rebuilds). Email Ready: blank rows + pivot cache + hidden sheets + comments + metadata (author, company). Maximum: all optional data. Data, formulas, calculations, formatting ALWAYS preserved. Images optimized based on quality setting.
This tool is 100% browser-based—Excel files never leave your device. Processed locally using JSZip + browser-image-compression + SheetJS. No upload to servers, no storage, no exposure. For business spreadsheets (financial data, sales data, HR data, proprietary formulas), browser-based processing is the only secure option. GDPR compliant by design—no data collection possible.
Reduce size 40-80% with automated multi-level optimization. Choose High Quality (charts/reports), Balanced (recommended), Email Ready (<20mb (smallest). ), always and browser, data files formulas in maximum never or p perfectly. preserved private stay uploaded.< your>
