How to compress video, images and PDF: settings by situation

Common file size limits

Before compressing, check where the file is going and how much the recipient accepts. These are common limits as of September 2026. Platforms change their rules, so treat the message you see when sending as the final word.

Leave headroom: set the target about 10% below the limit. The target size is an estimate, so check the actual output size before downloading.

Video: hitting a target size, and whether to lower resolution

Phone videos are large because of resolution and bitrate (4K, 60 fps), not length. One minute of 4K footage is often 300–400 MB. The same minute at 1080p with a normal bitrate is usually 30–80 MB, and 720p is smaller still. Actual results depend on the footage: fast motion and fine detail need more bits.

Sending to a service with a size limit

1. Open the video compressor and choose a file. MP4, MOV, MKV, AVI, WebM and other common formats are accepted; the output is MP4.
2. Enter a target size or pick a preset. Leave about 10% below the platform limit.
3. Trim first if you only need part of the clip. Halving the duration roughly halves the size, which costs less quality than squeezing the bitrate.
4. When it finishes, check the actual size, play a few seconds to confirm picture and sound, then download.

Just making it smaller, no hard limit

• Quality: start with Balanced. Step up one level if it looks soft, step down if it is still too large. There is rarely a reason to start at the smallest setting.
• Resolution: 720p is enough for phone viewing; keep 1080p for TVs and projectors. Going from 4K to 1080p usually cuts the size by more than half with little visible difference.
• Frame rate: 60 fps to 30 fps saves roughly another third to a half. Motion looks slightly less smooth, which rarely matters for everyday clips.
• Codec: H.264 plays everywhere and is the safe choice for sharing. H.265 is typically 20–40% smaller at the same quality, but older devices and some apps cannot open it, and it is only offered when your device has hardware support.

Why the file did not get smaller

If the source is already low-bitrate (a clip saved from WhatsApp, TikTok or a messaging app), re-encoding gains little and can even add a few percent. In that case only lowering resolution or trimming helps; otherwise keep the original.

Images: which format to choose, and how to get under 100 KB

Reaching a specific size (100 KB, 200 KB)

1. Reduce dimensions first. Phone photos are often 4000×3000 pixels; 800–1200 pixels is plenty for an avatar or ID photo, and this step alone can cut the size to under a tenth.
2. Then lower quality. JPEG or WebP at quality 75–85 is indistinguishable for most viewers; visible softness starts below about 60.
3. Keep transparent images as PNG or WebP. Converting to JPEG fills transparent areas with black or white.

Why screenshots get bigger, not smaller

Screenshots are usually PNG with lots of text and sharp lines. Converting them to JPEG produces fringing around text and is not always smaller. Keep screenshots as PNG and reduce dimensions, or convert to WebP.

Each image is limited to 100 MB and 40 megapixels. Batch processing and ZIP download are supported. Open the image compressor to start.

PDF: fitting an email limit, and why scans resist compression

Large PDFs are almost always large because of images: scanned pages, photos, high-resolution screenshots, full-page graphics. A text-only PDF is already small and has little left to compress.

Choosing between the two modes

• Try Smart mode first (or open the 1MB / 2MB PDF Compressor). If a long scanned packet still exceeds a strict portal cap, use Split PDF by File Size to divide it into clean MB-capped parts rather than blurring text.
• Each file in compression mode is limited to 100 MB. Owner print/copy restrictions are cleared automatically, or you can use Unlock PDF, Remove Blank Pages, and Merge PDF & HEIC directly in the workbench.
• Page through the result: text should stay legible, page count unchanged, signatures and stamps still readable.
• Open the PDF compressor to start.

Slow, failed, or the result looks wrong

• Slow: video encoding is heavy work. When no hardware encoder is available, the tool falls back to software encoding, which can be several times slower and needs a larger one-time engine download. Keep the tab in the foreground, close other memory-hungry tabs, and use a computer for large files.
• Failed: process fewer files at once, or test with a smaller file. The software encoding path has an input limit of about 2 GB; trim longer files first or use a computer.
• Blurry: step quality up one level or keep the original resolution and run again. Footage with text is more sensitive to compression, so err on the larger side.
• Word, Excel, PowerPoint: not supported directly. Export to PDF first, compress with the PDF tool, then check the layout.
• Where is the result: compression never overwrites your original; it creates a new file that you download. Save what you need before closing the page.

Why nothing is uploaded

Video, image and PDF compression run on encoders built into your browser (WebCodecs and WebAssembly). By default your files are not sent to a server. That is also why a 1 GB video does not need a half-hour upload first: speed depends on your computer or phone, not your connection. Temporary data in the browser is released when you close the page.

Compare local browser processing against upload-based converters on our FreeConvert Alternative, Watermark-Free Clideo Alternative, and Browser HandBrake Alternative pages. Details on telemetry and data handling are in the privacy notes.

Browsers and devices

Use a recent version of Chrome, Edge or Safari. The video tool checks what your device supports: it uses hardware encoding when available and software encoding otherwise.

Desktop Chrome, Firefox and WebKit have been verified with real file exports. Mobile browsers work, but speed and the largest file you can process depend on device memory. In-app browsers inside messaging apps may block downloads; open the page in the system browser and keep it in the foreground.