Images
Resize, crop, rotate and convert images. Edit photos, add watermarks, create memes and remove photo metadata.
Online tools for images,
PDFs and spreadsheets.
Resize photos, convert documents, clean spreadsheet data and check engineering files. Choose a tool, add your files or text, and download the result without creating an account.
CHOOSE YOUR TASK
Resize, convert and check your files
Bulk image resizer
Resize JPG, PNG and WebP photos by percentage or maximum dimensions. Keep the aspect ratio and download a batch of resized images.
Open tool →Merge PDF
Combine PDF documents into one file in your chosen order.
Open tool →Document to Markdown
Convert supported Office documents, PDFs and text files into editable Markdown.
Open tool →CSV to JSON
Convert CSV rows into JSON objects while preserving text values.
Open tool →Survey spreadsheet cleaner
Convert multi-select survey answers from Google Forms or Microsoft Forms CSV exports into separate yes/no columns without duplicating respondents.
Open tool →Modbus register map checker
Check Modbus register addresses, overlapping ranges and declared data widths. Download a findings CSV and printable register map documentation.
Open tool →Find a tool for your file or workflow
Use the format you have or the task you need to finish as your starting point. Each category links to tools with instructions, supported inputs and downloadable results.
Merge, split, sign and organize PDF pages. Fill PDF forms, add watermarks, extract pages and compare document versions.
Documents
Convert Office documents, prepare EPUB ebooks, check ebook errors and package linked Markdown notes for sharing.
Excel & CSV
Clean and combine spreadsheet exports. Convert CSV and JSON, compare records, select columns and prepare data for Excel.
Audio & video
Check video codecs, adjust subtitle timing, remove recording pauses and normalize podcast audio loudness.
Text & developer
Format JSON, compare text, count words, encode URLs, create passwords and check file hashes. Find timers and date calculators.
Engineering
Check Modbus maps, cable schedules and PLC–HMI tags. Align sensor recordings, compare BOM revisions and convert engineering units.
Business
Generate barcode labels and certificates, build campaign tracking links and turn event spreadsheets into calendar files.
HR & work
Calculate shift hours and working days, review course attendance, check training expiry dates and extract email lists.
Study
Calculate weighted grades, build study plans and export Anki flashcards. Prepare classroom data with focused student tools.
Design & making
Create favicons, check color contrast, subset fonts, optimize 3D models and prepare laser-cut, embroidery and organizer files.
How to use the online tools
File processing explained →Choose files or import a URL
Open the tool for your task. Choose files, drag and drop them, or import a direct public file link. Use pasted text where the tool supports it.
Review the settings and examples
Choose dimensions, output formats, spreadsheet columns or matching rules. Check the example and file limits before processing.
Download and review the result
Save the converted file or report. Check the output before importing it into another application, printing it or sharing it with your team.
Questions about file conversion and online tools
Are these online tools free to use?
OpenToolDesk tools are free to use without an account or subscription. File size, batch size and supported format limits are listed on each tool page.
Can I use the tools on a phone or tablet?
Yes. The pages adapt to desktop, tablet and mobile screens. You can choose files from your device instead of dragging them. Large files and batches may need more memory, so start with a smaller batch on a phone.
Can I paste text instead of uploading a file?
Tools that support pasted input show a Paste text option after the upload area. You can also import a direct public file URL where supported. If you select a file, it takes priority over pasted text.
How do I choose the right file conversion tool?
Start with the format you have and the result you need. For example, use CSV to JSON for application data, Document to Markdown for editable document text, or Bulk image resizer for photo dimensions. Read the supported formats and limitations on the tool page.