What is the best image format for websites?

WebP is the best all-around image format for websites in 2026. It offers 25-35% smaller files than JPEG at the same quality, supports transparency like PNG, and has 97% browser support. Use JPEG as a fallback for older browsers, and SVG for logos and icons.

What is the difference between lossy and lossless compression?

Lossy compression permanently removes some data to achieve smaller files — you cannot restore the original. JPEG, MP3, and MP4 are lossy. Lossless compression reduces file size without any data loss — the original can be perfectly reconstructed. PNG, FLAC, and WAV are lossless. Lossy is better for sharing and web use; lossless is better for editing and archiving.

Should I use PDF or DOCX for sharing documents?

Use PDF when you want the document to look identical on every device and prevent easy editing. Use DOCX when the recipient needs to edit the content. PDF preserves fonts, layout, and formatting exactly. DOCX may render differently depending on the recipient's version of Word or alternative software.

What video format should I use for uploading to social media?

MP4 with H.264 encoding is the safest choice — every major platform accepts it. Use 1080p resolution at 30fps for the best balance of quality and file size. Most platforms re-encode your video anyway, so uploading at higher than 4K is rarely beneficial.

Is HEIC better than JPEG?

HEIC produces files roughly 50% smaller than JPEG at the same visual quality. However, HEIC has limited compatibility outside the Apple ecosystem. For sharing, convert HEIC to JPEG or WebP for maximum compatibility. For personal storage on Apple devices, HEIC saves significant space.

The Complete File Format Cheat Sheet: Image, PDF, Video, Audio & Document Formats

Every common file type explained — sizes, uses, and compatibility at a glance

By Ben Praveen J · March 24, 2026

There are hundreds of file formats, and choosing the wrong one wastes storage, breaks compatibility, or degrades quality. This cheat sheet covers every format you are likely to encounter — images, documents, video, and audio — with clear guidance on when to use each one.

Bookmark this page. You will come back to it.

Image Formats

Image formats fall into two camps: lossy (smaller files, some quality loss) and lossless (perfect quality, larger files). Choosing the right one depends on whether you are publishing to the web, printing, or editing.

Format	Type	Transparency	Best For	Typical Size	Browser Support
JPEG (.jpg)	Lossy	No	Photos, web images	~97% smaller than raw	100%
PNG (.png)	Lossless	Yes	Graphics, logos, screenshots	2-5x larger than JPEG	100%
WebP	Both	Yes	Web images (all types)	25-35% smaller than JPEG	97%
GIF	Lossless (256 colors)	Yes (1-bit)	Simple animations, icons	Varies widely	100%
SVG	Vector	Yes	Logos, icons, illustrations	Very small (text-based)	100%
HEIC	Lossy	No	iPhone photos, Apple ecosystem	~50% smaller than JPEG	Safari only
AVIF	Both	Yes	Next-gen web images	~50% smaller than JPEG	85%
TIFF (.tif)	Lossless	Yes	Print, archival, professional editing	Very large (uncompressed)	None (needs viewer)
BMP	Uncompressed	No	Legacy Windows applications	Extremely large	100% (but never use on web)
ICO	Lossless	Yes	Favicons, Windows icons	Very small (16x16 to 256x256)	100%

When to Use Which Image Format

Photograph for the web? Use WebP. If you need maximum compatibility, use JPEG. Convert images here.
Logo or icon? Use SVG if possible (infinitely scalable). If not, use PNG for transparency or WebP.
Screenshot or graphic with text? Use PNG. Text stays sharp because there is no lossy compression.
Short animation? Use GIF for simple loops under 5 seconds. For longer or higher-quality animations, use MP4 video instead.
Photos from an iPhone? HEIC saves space on your phone but convert to JPEG or WebP before sharing. Convert HEIC here.
Professional print? Use TIFF or high-quality PNG. Never use JPEG for print — compression artifacts become visible.
Maximum compression, modern browsers? Use AVIF. It produces the smallest files but has 85% browser support, so provide a JPEG or WebP fallback.

Convert between any image format: Image Converter — supports JPEG, PNG, WebP, GIF, AVIF, TIFF, BMP, and more. Free, instant, no signup.

Document Formats

Document formats determine whether your file preserves layout, allows editing, or works across platforms. The wrong choice leads to broken formatting or recipients who cannot open your file.

Format	Editable	Layout Preserved	Best For	Opens With
PDF	Limited	Yes (exactly)	Sharing final documents, forms, contracts	Any browser, Acrobat, Preview
DOCX	Yes	Mostly (depends on fonts)	Editable documents, collaboration	Word, Google Docs, LibreOffice
XLSX	Yes	Mostly	Spreadsheets, data tables, calculations	Excel, Google Sheets, LibreOffice
PPTX	Yes	Mostly	Presentations, slide decks	PowerPoint, Google Slides
TXT	Yes	None (plain text)	Notes, code, logs, configuration files	Any text editor
RTF	Yes	Basic formatting	Cross-platform formatted text	Most word processors
ODT	Yes	Mostly	Open-source alternative to DOCX	LibreOffice, Google Docs
CSV	Yes	None (structured data)	Data exchange, imports, exports	Any spreadsheet app, text editor

When to Use Which Document Format

Sending a final document someone should not edit? Use PDF. Layout is preserved exactly on every device.
Collaborating on a document? Use DOCX (or Google Docs) for real-time editing and track changes.
Sharing data or numbers? Use XLSX for complex data with formulas. Use CSV for simple data that needs to be imported into other tools.
Need to convert between formats? Convert PDF to DOCX for editing, or save DOCX as PDF for sharing.
Maximum compatibility? TXT works everywhere but has no formatting. PDF works everywhere and preserves formatting. Choose based on whether formatting matters.

Video Formats

Video formats are containers that hold video and audio streams encoded with specific codecs. The container determines compatibility; the codec determines quality and file size.

Format	Codec	Best For	Typical Size (1 min, 1080p)	Compatibility
MP4 (.mp4)	H.264 / H.265	Everything — web, social, sharing	~50-150 MB	Universal
MOV	H.264 / ProRes	Apple ecosystem, professional editing	~100-500 MB	Apple + most players
WebM	VP9 / AV1	Web embedding, HTML5 video	~30-100 MB	Chrome, Firefox, Edge
AVI	Various	Legacy Windows applications	~200-500 MB	Windows-focused
MKV	Any codec	Archival, multiple tracks, subtitles	Varies by codec	VLC, most desktop players
GIF (animated)	None (frames)	Short loops, reactions, demos	~5-50 MB (very inefficient)	Universal

When to Use Which Video Format

Uploading to social media or sharing? Use MP4 with H.264. Every platform accepts it, every device plays it.
Editing in Final Cut Pro or Apple workflow? Use MOV with ProRes for highest editing quality. Export to MP4 for sharing.
Embedding video on a website? Use MP4 as the primary source. Add WebM as a fallback for slightly better compression.
Archiving with subtitles and multiple audio tracks? Use MKV — it supports virtually any codec and unlimited tracks.
Short clip or reaction? Consider MP4 over GIF. A 10-second GIF can be 20 MB; the same clip as MP4 is under 2 MB. Compress video here.

Video too large? Compress your video — reduce file size by 50-80% without visible quality loss. No signup, no watermark.

Audio Formats

Audio formats trade off between file size and quality. For casual listening, lossy formats are indistinguishable from lossless. For production and archiving, lossless is essential.

Format	Type	Quality	Typical Size (1 min)	Best For
MP3	Lossy	Good (128-320 kbps)	~1-2.5 MB	Music sharing, podcasts, universal playback
AAC (.m4a)	Lossy	Better than MP3 at same bitrate	~1-2 MB	Apple ecosystem, streaming, modern devices
WAV	Uncompressed	Perfect (CD quality)	~10 MB	Audio production, editing, recording
FLAC	Lossless	Perfect (compressed)	~5-7 MB	Audiophile listening, archival, high-end streaming
OGG (.ogg)	Lossy	Good (similar to MP3)	~1-2 MB	Open-source applications, web audio, games

When to Use Which Audio Format

Sharing music or podcasts? Use MP3 at 192-320 kbps. Universal compatibility, good quality, reasonable size.
Apple device or iTunes? Use AAC. Better quality than MP3 at the same file size, and native to all Apple devices.
Recording or editing audio? Use WAV. No compression means no generation loss when editing and re-saving.
Archiving a music collection? Use FLAC. Perfect quality in half the space of WAV, and you can always convert to MP3 or AAC later.
Web application or game? Use OGG. Open source, no licensing fees, and supported natively in most browsers.

Quick Conversion Reference

Here are the most common format conversions and where to do them:

JPEG / PNG / HEIC to WebP: Image Converter — reduces file size while maintaining quality.
PNG to JPEG: Image Converter — useful when you do not need transparency and want smaller files.
Any image, reduce file size: Image Compressor — keeps the same format, reduces size by 40-80%.
PDF to DOCX: PDF to Word Converter — makes PDFs editable.
Large video, reduce size: Video Compressor — shrinks MP4, MOV, WebM files significantly.

File Size Comparison at a Glance

To illustrate how dramatically format choice affects file size, here is the same content saved in different formats:

A 4000x3000 photograph:

BMP (uncompressed): ~36 MB
TIFF (lossless): ~36 MB
PNG (lossless): ~15 MB
JPEG (quality 85): ~2 MB
WebP (quality 85): ~1.4 MB
AVIF (quality 85): ~1.0 MB

That is a 36x difference between BMP and AVIF for the same photograph at visually identical quality. Format choice matters enormously.

A 3-minute audio clip:

WAV (uncompressed): ~30 MB
FLAC (lossless): ~18 MB
MP3 (320 kbps): ~7 MB
MP3 (128 kbps): ~3 MB
AAC (128 kbps): ~2.5 MB

FAQ

What is the best image format for websites?: WebP is the best all-around choice in 2026. It supports both lossy and lossless compression, transparency, and has 97% browser support. It produces 25-35% smaller files than JPEG at the same quality. Use JPEG as a fallback for the remaining 3% of browsers, and SVG for logos and icons that need to scale.
What is the difference between lossy and lossless compression?: Lossy compression permanently removes some data to achieve smaller files — the original cannot be reconstructed. JPEG, MP3, and MP4 are lossy. Lossless compression reduces size without any data loss — the original can be perfectly restored. PNG, FLAC, and WAV are lossless. For sharing and web use, lossy is typically fine. For editing and archiving, always use lossless.
Should I use PDF or DOCX for sharing documents?: Use PDF when you want the document to look identical on every device and prevent easy editing. Use DOCX when the recipient needs to edit the content. PDF preserves fonts, layout, and formatting exactly. DOCX may render differently depending on the recipient's software. When in doubt, send a PDF.
What video format should I use for uploading to social media?: MP4 with H.264 encoding is the universal choice. Every major platform — YouTube, Instagram, TikTok, Twitter/X, Facebook, LinkedIn — accepts MP4. Use 1080p resolution at 30fps for the best balance of quality and file size. Most platforms re-encode your video regardless of what you upload.
Is HEIC better than JPEG?: HEIC produces files roughly 50% smaller than JPEG at the same visual quality, which is a significant advantage for phone storage. However, HEIC has limited compatibility outside Apple devices. For sharing, convert HEIC to JPEG or WebP. For personal storage on an iPhone, HEIC saves significant space without any visible quality loss.