What is the ASS format?

Advanced SubStation Alpha (.ass) is a styled subtitle format that supports fonts, colours, outlines, shadows, positioning and animation. It is the standard for fansubs and MKV soft-subs because it can render rich styling that plain SubRip cannot.

How are SRT timestamps converted?

SubRip times are given to the millisecond (hh:mm:ss,ms) while ASS uses centiseconds (h:mm:ss.cc). The converter rounds the milliseconds to the nearest centisecond and writes ASS's single-digit-hour timing format.

Do italic and bold tags carry over?

Yes. SubRip inline tags for italic, bold and underline are translated to ASS override codes such as the italic-on and italic-off codes, so the styling appears in the rendered subtitle.

How do the colour controls map to ASS?

ASS stores colours as &HBBGGRR& (blue-green-red) hex with an alpha byte. The converter takes the colour you pick, reverses the channel order, and writes it into the Default style's PrimaryColour and OutlineColour fields.

Is anything uploaded?

No. The SRT is parsed and the ASS script is built entirely in your browser. Your subtitles are never sent to a server, so unreleased captions stay on your device.

What is the SRT to ASS / SSA Converter?

Convert SubRip (.srt) subtitles to Advanced SubStation Alpha (.ass) with a configurable default style: font, size, text and outline colour, bold, italic, outline and shadow. Maps SRT cues to Dialogue lines and converts inline tags. Browser-only, ideal for MKV soft-sub workflows. It runs free in your browser on Gera Tools, with nothing uploaded.

SRT to ASS / SSA Converter

Name: SRT to ASS / SSA Converter
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Advanced SubStation Alpha (.ass, the successor to .ssa) is the subtitle format used whenever captions need real styling — custom fonts, coloured text, outlines and shadows — which is why it dominates fansubbing and MKV soft-sub workflows. Plain SubRip can’t express any of that. This converter takes an .srt and wraps it in a complete ASS script with a default style you control.

How it works

An ASS file has three sections, all of which the converter generates:

[Script Info] — metadata including the playback resolution (PlayResX / PlayResY) you set, so styling scales correctly to your video.
[V4+ Styles] — a single Default style built from your controls: font name and size, primary (text) colour, outline colour, bold and italic flags, and outline and shadow thickness.
[Events] — one Dialogue line per subtitle cue.

For each SubRip cue the converter:

Converts the timestamps. SubRip uses milliseconds (00:00:01,000); ASS uses centiseconds with a single-digit hour (0:00:01.00). The milliseconds are rounded to the nearest centisecond.
Translates inline tags. SubRip’s <i>, <b> and <u> become ASS override codes — for instance italic maps to the italic-on code and its closing tag to the italic-off code. Unsupported HTML-style tags are stripped, and hard line breaks become ASS’s \N.
Emits the Dialogue line referencing the Default style.

Colour handling

ASS stores colours in &HBBGGRR& order (blue, green, red) — reversed from the usual #RRGGBB. When you pick a colour the converter reverses the channels and writes it into the style’s PrimaryColour (text) and OutlineColour fields with an opaque alpha byte.

Tips

Set the width and height to match your video (1920×1080 by default) so the font size and outline render at the intended scale.
A small outline (1–3 px) with no shadow keeps subtitles readable over varied backgrounds; increase the shadow for extra contrast on bright footage.
To soft-sub an MKV, mux the generated .ass alongside the video with a tool like mkvmerge; players that support ASS will render the styling.
Everything runs in your browser — your subtitles are never uploaded.