Free Browser-Based Converter
ConvertCraft is a free online file conversion platform with 125+ tools. Every conversion runs locally in your browser using WebAssembly. Your files never leave your device for standard operations — no uploads, no cloud processing, no sign-ups required.
ConvertCraft is a privacy-first file conversion suite designed for creators, developers, and everyday users who need fast, reliable file processing without compromising their data. Unlike traditional cloud-based converters that upload your files to remote servers, ConvertCraft processes files directly inside your web browser using WebAssembly (WASM) technology. This means your documents, photos, audio tracks, and video clips stay on your device throughout the entire conversion process.
The platform covers nine categories of tools — Image, Video, Audio, PDF, Archive, Documents, Crypto Utilities, Security, and AI-powered features — totalling over 125 individual converters and utilities. Every tool is free to use. There is no mandatory account creation, no email requirement, and no imposed limits on the number of conversions you can run in a session.
ConvertCraft uses a local-first architecture. When you select a file and choose an output format, the entire encoding and decoding pipeline runs in your browser's sandboxed environment. The conversion engine is built on FFmpeg.wasm for media operations (video, audio, GIF) and Canvas API with typed arrays for image processing. PDF tools use client-side JavaScript libraries with optional server-assisted rasterization for edge cases that require Poppler-level accuracy.
Convert between PNG, JPEG, WebP, AVIF, GIF, BMP, TIFF, and HEIC. Batch-convert entire folders, crop images to exact dimensions, add watermarks, apply filters (blur, sharpen, sepia, grayscale), create collages, remove backgrounds with AI, and sanitize metadata to strip EXIF location data before sharing files online. The image converter supports quality control and maximum dimension constraints, so you can compress images for web use without manual resizing.
Trim, merge, compress, and convert video files between MP4, MOV, WebM, and AVI. Extract audio from video files, create animated GIFs from video clips with configurable frame rate and palette optimization, add subtitle overlays, apply color correction, adjust playback speed, stabilize shaky footage, and burn timecodes. Video processing runs entirely through FFmpeg.wasm in your browser — no file uploads to external servers.
Convert between MP3, WAV, OGG, FLAC, AAC, and M4A. Apply fade-in and fade-out effects, trim audio to precise timestamps, mix multiple tracks, detect beats per minute, equalize frequency response, remove background noise, reverse playback, remove silence, and edit ID3 metadata tags. Audio tools are useful for podcasters, musicians, and content creators who need quick format changes without installing desktop software.
Merge multiple PDFs into one document, split a PDF by page ranges, compress PDF file size for email attachments, convert PDF pages to images (PNG or JPEG) at custom DPI, add page numbers, insert bookmarks, protect PDFs with passwords, remove existing password locks, extract text via OCR, fill form fields, compare two PDF versions side by side, and convert between PDF and DOCX. PDF operations that can run client-side do so automatically; server-assisted rasterization is available for complex documents.
Create and extract ZIP archives, extract 7Z files, convert between ZIP and ISO formats, inspect EPUB ebook metadata, convert DOCX to PDF and PDF to DOCX. These tools let you manage compressed files and office documents directly in your browser without installing dedicated archive or office software.
ConvertCraft includes a set of practical crypto and security utilities: convert between BTC satoshis and ETH gwei, estimate gas fees, calculate profit/loss and DCA (dollar-cost averaging) returns, validate mnemonic seed phrases and crypto addresses, check SSL certificates, verify file checksums (SHA-256, MD5), generate secure passwords, encrypt and decrypt files with AES, hide data inside images using steganography, and scan QR codes. These tools run entirely client-side for zero-exposure workflows.
Most online converters work by uploading your file to a remote server, processing it there, and sending back a download link. During that round trip, your file contents are exposed to the server operator's infrastructure, retention policies, and any third-party services they use. For sensitive files — tax documents, legal contracts, medical records, client deliverables, personal photos — this creates risk you cannot audit or control.
ConvertCraft eliminates this risk for the majority of operations by running conversions inside your browser. The WASM engine handles codec-heavy workloads locally, using your own CPU and memory. Files are read into browser memory, processed through typed-array pipelines, and output as downloadable blobs — without ever crossing a network boundary. For the small number of edge-case operations that require server assistance (certain PDF rasterizations or proxy-backed network checks), the data transfer is transient and auto-deleted within minutes.
To help users make better file decisions beyond one-click conversion, ConvertCraft publishes in-depth educational content with practical workflows, quality benchmarks, and privacy checklists. Start with these cornerstone articles:
Browse the full editorial hub at ConvertCraft Articles for continuously updated best practices.
Most conversions run locally in your browser via WebAssembly, so files generally stay on-device. For edge-case helper workflows, processing is limited, temporary, and aligned with short retention handling.
ConvertCraft covers images, video, audio, PDF, archives, and utility workflows. Common examples include JPG, PNG, WebP, MP4, MOV, WAV, MP3, PDF, ZIP, and 7Z, with many additional specialized options.
Use a high-quality source, test one sample first, then scale with fixed presets. Keep an untouched original so you can regenerate final outputs without compounding quality loss from repeated re-encoding.
Performance depends on source complexity, output settings, and available device resources. Larger files and stronger compression settings take more time, while tested presets and lighter system load improve consistency.
Yes. The interface is responsive and supports modern mobile browsers. Medium workloads usually run smoothly, while very large media files are typically faster and more stable on desktop hardware.
Core tools are free, with limits based on workload type. If you hit a cap, you can optimize settings, split large jobs, or use upgraded plans when you need higher throughput and larger allowances.
Choose based on destination and compatibility. JPG or PNG are common image defaults, MP4 is broadly compatible for video, MP3 works for many audio scenarios, and PDF remains standard for document sharing.
Yes. The best process is to validate one representative sample first, lock your settings, then process the remaining files in a batch. This improves consistency and reduces avoidable rework.
Retry using a standard output format and conservative settings, then confirm destination app support. Testing with a smaller source file helps isolate whether the issue comes from settings or source complexity.
Visit the ConvertCraft Articles hub for in-depth guides on file formats, quality retention, privacy-first workflows, troubleshooting, and scalable batch conversion strategy.