Convert to XLSX | Fast & Free & Secure
Convert to XLSX online in seconds. No signup. Secure processing; files auto-delete in ~2h. Works on mobile & desktop.
Smart Auto-Detection – ConvertSea
No need to select your file type — we've already detected it.
Just upload your file and choose the format you want to convert it to. Our system automatically recognizes the input format, so you can focus on getting the output you need.
What is XLSX?
XLSX is the modern Microsoft Excel workbook format introduced with Office 2007. Based on the Office Open XML standard, an .xlsx file is a compressed package of XML parts that describe worksheets, cells, styles, and embedded media. This structure makes files smaller, more resilient, and easier to recover than the legacy .xls. XLSX supports formulas and functions, tables, named ranges, data validation, conditional formatting, charts, and pivot tables. Because it does not contain VBA macros (those use .xlsm), it’s generally safer to share. You can open or edit XLSX with Excel, Google Sheets, LibreOffice Calc, and Apple Numbers, and convert it to CSV, PDF, or other formats. Common uses include budgets, dashboards, financial models, logs, and scientific datasets where precise calculation and layout matter.
Upload Your File
Upload your file (drag & drop or click). Input type is auto-detected—no need to choose it.
Pick Format & Options
Pick the output format and (if available) adjust options like OCR, quality, bitrate, or resolution.
Convert & Download
Convert & download your file. Rate us.
Convert Your Files Instantly – Fast, Secure & Free
Welcome to ConvertSea, the ultimate online tool to convert your files with speed, accuracy, and zero hassle. Whether you're changing image formats, converting videos, editing documents, or extracting audio, our platform delivers instant, high-quality results across hundreds of file types.
No downloads, no registration, and no watermarks — just upload your file, choose the format you need, and download your converted file in seconds.
From PDF to Word, MP3 to WAV, JPG to PNG, or MP4 to MOV, ConvertSea ensures that your content stays clean, secure, and exactly how you want it.