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The answers behind the tools
29 guides and comparisons
Why a file is the size it is, which format to pick, and what a conversion actually costs you. Each one ends at the tool that does the job, and every claim is one we can stand behind.
11 guides
Images
Formats, file sizes and what a photo gives away.
- What is a HEIC file, and how do you open one? HEIC is the photo format iPhones and iPads have used by default since iOS 11.
- Why are iPhone photos so big? Because the camera is genuinely capturing more: 12 to 48 megapixels, extra brightness range for HDR, and often a three-second video attached to every shot.
- What your photos quietly tell people Most photos carry EXIF metadata: GPS coordinates accurate to a few metres, the exact time, the camera or phone model and its serial number, and often the settings and software used.
- Lossy vs lossless, in practice Lossless compression stores the file in less space and gives back every original bit.
- Which image format belongs on your website? Use SVG for logos and icons, AVIF or WebP for photographs, and PNG only for images that need exact pixels or must work in old software.
Which format should you use?
10 guides
Video
Containers, codecs, and why clips are the size they are.
- Container vs codec A container (MP4, MKV, MOV, WebM) is the box that holds the streams and keeps them in sync.
- H.264 vs H.265 vs AV1 H.264 plays on everything and should be your default for any video you send to someone.
- Why is my video file so big? File size is bitrate multiplied by duration, and bitrate is driven by resolution, frame rate and how much movement there is.
- How to compress a video without wrecking it Truly lossless compression of video barely exists in practice, but most of the size can go before anything is visible.
- How to play an MKV on an iPhone Apple’s built-in player does not support the MKV container at all, whatever is inside it.
- GIF vs MP4: why GIFs are so big GIF stores every frame as a separate 256-colour image with no motion compression, so a few seconds becomes tens of megabytes.
Which format should you use?
8 guides
Audio
Loudness, bitrate, and what to publish in.
- What LUFS is, and the number to aim for LUFS is a measure of perceived loudness across a whole recording.
- What format should a podcast be? Record and edit in WAV, publish as MP3 at 96–128 kbps mono for speech, or 128–192 kbps stereo if there is music.
- Bitrate and sample rate, explained Bitrate is how much data per second a lossy file is allowed, and it is what decides both quality and file size.