Can I convert horizontal 16:9 video to vertical 9:16 for Reels or TikTok?

Yes. Selecting the 9:16 vertical preset automatically frames the center of your landscape video into portrait format, perfect for Instagram Reels, YouTube Shorts, and TikTok.

Does cropping video re-encode the audio?

No. The audio stream is extracted and multiplexed directly into the new MP4 container without re-encoding, preserving 100% original audio fidelity with zero sync drift.

Can I adjust the crop position so subjects stay centered?

Yes. In addition to preset aspect ratios, you can adjust the X and Y offset coordinates to reposition the crop window over the most important part of your frame.

Will there be any watermark on the cropped video?

No. Output video files are completely clean with zero watermarks, logos, or restrictions. The content remains entirely yours.

Are video frames uploaded to a server during cropping?

No. The entire cropping and re-encoding process runs locally on your device within your browser tab under strict Content Security Policies.

Crop Video Online

Trim video canvas aspect ratios (1:1, 9:16, 4:5, 16:9) in your browser without uploading. No watermark.

100% Client-Side

About this video cropping tool

Select an MP4 or MOV video file, pick an aspect ratio preset (1:1 Square, 9:16 Vertical Story/Reel, 4:5 Portrait, or 16:9 Landscape) or enter custom crop dimensions, and click Crop Video. The video is cropped and re-encoded using browser WebCodecs hardware acceleration, with original audio passed through untouched.

Adapting horizontal video recordings for vertical social platforms like Instagram Reels, TikTok, and YouTube Shorts often forces creators to upload private videos to third-party web services that add watermarks or re-compress audio. This tool performs precision video cropping inside your browser using GPU-backed canvas viewport slicing and WebCodecs hardware encoding. The picture is cropped to your exact framing while preserving the original audio track without any loss.

Runs in this tab — no uploadFree, no account, no watermark

Step by step

1Select input videoChoose an MP4 or MOV video file up to 2 GB. The demuxer reads track geometry, display matrix flags, and audio configurations from the movie atom.
2Choose target aspect ratioSelect a social media preset (such as 1:1, 9:16, 4:5, or 16:9) or adjust width, height, and offset coordinates. The tool centers the crop box or lets you position it precisely.
3Hardware canvas cropping and re-encodingClick Crop Video. Each video frame is drawn to a canvas at the specified sub-rectangle offset and piped directly to the hardware VideoEncoder with backpressure control.
4Export cropped MP4Save the cropped MP4 video to your drive. The tool constructs fresh visual sample descriptions (stsd/avc1/avcC) and multiplexes the re-encoded frames with the original audio.

Canvas viewport clipping and spatial offsets

Cropping video requires redefining the spatial boundaries of each frame. Rather than masking pixels with black letterboxing bars, our engine extracts the exact sub-region you specify. By drawing the source frame to an internal canvas using source coordinates (sx, sy, sw, sh) mapped to destination coordinates (0, 0, dw, dh), unwanted edges are completely discarded. The resulting video file contains only the cropped visual area, reducing unnecessary data overhead.

Optimized for vertical and square social formats

Converting standard 16:9 landscape video into 9:16 vertical video for mobile stories or 1:1 square for feed posts is seamless. Presets automatically compute the maximum centered crop area that fits within your source video bounds while ensuring even pixel dimensions for H.264 macroblock compliance. You can also fine-tune the horizontal and vertical offsets to keep key subjects centered in frame.

Preserving original audio fidelity

Cropping modifies only visual pixel geometry, so re-encoding the audio track would be completely counterproductive. Our engine demuxes the original compressed audio packets (such as AAC) and passes them directly through into the output container without decoding or transcoding. Your dialogue, soundtrack, and ambient audio retain their full original clarity without generational loss or sync drift.

Hardware-accelerated encoding with backpressure regulation

Processing thousands of high-definition video frames requires careful resource management. By pairing native WebCodecs VideoDecoder with hardware-accelerated VideoEncoder and throttling frame delivery via encoder.encodeQueueSize, this tool prevents browser memory spikes. You get smooth, responsive video processing that runs directly on your local GPU without heating up your computer or crashing the browser tab.

Zero upload security guarantee

Every response from this site is served with a Content Security Policy whose connect-src directive is set to none. That is not a promise in marketing copy; it is an instruction to your browser, and the browser is the one enforcing it. While this page is open it cannot open a connection to anywhere — not to this site, not to anyone else — so there is no path by which your document could be uploaded, not by a bug, not by a future change, not by a script that should not be here. e2e/egress-proof.spec.ts asserts the served header and then tries to send data out by every route a page has and requires each attempt to be refused, and it runs on every build.

The second half of the guarantee is that the code has nowhere to send anything from. lib/tools/local-source-policy.test.ts reads every source file under lib/tools, workers, components and app on every test run and fails the build if any of them contains fetch, XMLHttpRequest, WebSocket, EventSource, sendBeacon or a peer connection, or even a remote address written down in a comment. A tool here cannot acquire an upload by accident, because the file that would have to contain one cannot be committed.

Client-side processing limits

Computations run directly on your own device using WebAssembly, Web Workers, and modern browser APIs including Web Crypto and TextDecoder. There are no server queues, no background telemetry, and no temporary cloud files created. Large operations remain responsive by offloading heavy parsing and conversion tasks to dedicated worker threads, ensuring the browser UI never freezes during intensive document and data processing tasks.

Questions people ask

Can I convert horizontal 16:9 video to vertical 9:16 for Reels or TikTok?: Yes. Selecting the 9:16 vertical preset automatically frames the center of your landscape video into portrait format, perfect for Instagram Reels, YouTube Shorts, and TikTok.
Does cropping video re-encode the audio?: No. The audio stream is extracted and multiplexed directly into the new MP4 container without re-encoding, preserving 100% original audio fidelity with zero sync drift.
Can I adjust the crop position so subjects stay centered?: Yes. In addition to preset aspect ratios, you can adjust the X and Y offset coordinates to reposition the crop window over the most important part of your frame.
Will there be any watermark on the cropped video?: No. Output video files are completely clean with zero watermarks, logos, or restrictions. The content remains entirely yours.
Are video frames uploaded to a server during cropping?: No. The entire cropping and re-encoding process runs locally on your device within your browser tab under strict Content Security Policies.

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