How to Add Subtitles to Instagram Reels

Instagram's auto-captions and where they fall short

Instagram can generate captions automatically, and for clear speech in a supported language they are decent. Where they struggle is exactly where accuracy matters most: names, brands, technical vocabulary, accents and any recording with background noise. They also give you no control over placement, so they routinely sit on top of the thing you are pointing at.

A workflow that works, step by step

This is the sequence we would follow for a Reel you care about. Steps 1 to 4 happen in MediaVault; the last step happens in whatever you post or edit with.

• 1. Reformat first. If the clip is landscape, use the video resizer to make it vertical 9:16 so your caption layout is final before you transcribe.
• 2. Open the AI subtitle generator, drop in the video and click the transcribe button. The Whisper model downloads to your browser on first use (the tool labels it about 75 MB for the Tiny model and about 140 MB for Base), then transcribes on your device.
• 3. Correct the text. Each caption line appears in an editable box with its start and end time. Fix names, brands and jargon there. You can change the words; the times are shown but not editable in the tool.
• 4. Download the SRT. SRT export is available on the free tier. A styled ASS export (font, colour and outline settings) is a Pro feature.
• 5. Put the captions on the Reel. Instagram does not take a caption file, so either type the corrected lines into Instagram's own text tools, or bring the SRT or ASS file into a video editor that can import subtitles and render them into the picture.

What MediaVault does not do here

It is worth being clear about the limits so you plan around them. The subtitle generator produces a transcript and caption files; it does not render captions onto the video itself, so any burning-in happens in another editor. The speech models offered are the English versions of Whisper (Tiny and Base), so it is built for English speech, and the Base model needs Pro. There is also a Translate Speech to English checkbox, but because the listed models are English-specific, test it on a short clip before relying on it for another language. Transcription lines follow the model's natural phrase breaks, so you will often want to shorten long lines by hand.

Burned-in captions versus platform captions

Burned-in captions are drawn into the video frames themselves, so they cannot be switched off, cannot be repositioned by the platform, and travel with the file when you post the same clip to TikTok or YouTube Shorts. The trade is that they are permanent — fixing a typo means re-rendering. Platform captions are editable and toggleable but stay behind on that platform.

• Cross-posting the same clip: burn them in once, use everywhere
• Precise placement matters: burn them in
• Might need to edit the text later: use platform captions

Captions people can actually read

Reels are watched on a phone, held at arm's length, often one-handed while walking. Text sized comfortably on your monitor is frequently unreadable there.

• Keep to one or two short lines at a time
• Stay out of the bottom fifth of the frame — the caption and UI live there
• High contrast: white text with a dark outline survives any background
• Check it on your own phone before posting, not on your laptop

Getting a more accurate transcript

Good captions start from a good transcript, and a transcript is only as good as the audio it hears. Background music and room noise are the biggest causes of mistakes, so record close to the microphone and keep music out of the clip you transcribe. If a recording is already noisy, clean the audio first with the audio denoiser, then transcribe. Whatever the audio, read the whole transcript once before exporting, because names, numbers and technical terms are where the errors cluster, and fixing them in a text box takes seconds, whereas fixing them after they are rendered into the video means starting over.

Keeping unreleased content off other people's servers

Captioning services want your video uploaded. For a Reel that is going public in an hour that may not bother you; for a client campaign under embargo, a product launch, or footage you have not cleared yet, it is a real exposure. Transcribing locally keeps the file on your device: the audio is decoded and transcribed inside your browser, and only the model files are downloaded.

A quick check before you post

Play the finished Reel on your phone with the sound off. If you can follow it from the captions alone, the text is readable, the timing is right and nothing is hidden behind the interface.

Frequently asked questions

Related tools

• Video Resizer — Reformat video to portrait, square or landscape for any platform.
• Audio Denoiser — Strip hum, hiss and rumble out of voice recordings.

Related guides

• How to compress video for email — Get a video under the 25MB attachment ceiling without uploading it anywhere.
• How to remove background noise from a podcast — What denoising can fix, what it cannot, and the order to do it in.