# Subtitle Quality Checker

> Check subtitles against broadcast standards for reading speed, line length and duration.

Subtitle quality standards exist because unreadable subtitles are worse than none. This checker tests reading speed in characters per second, characters per line, lines per cue, minimum and maximum duration, overlapping cues and gaps too small to register — against the values the BBC and Netflix publish.

**URL:** https://convertto.tech/t/subtitle-quality-checker
**Category:** Audio & Video Tools (https://convertto.tech/c/media-tools)
**Privacy:** Runs entirely in the browser; no upload
**Cost:** Free, no sign-up
**Last updated:** 2026-08-01

## Key facts

- **Checks:** Reading speed, line length, line count, duration, overlaps, gaps and empty cues
- **Based on:** BBC Subtitle Guidelines and the Netflix Timed Text Style Guide
- **Privacy:** Runs entirely in your browser — nothing is uploaded
- **Cost:** Free, unlimited, no sign-up

## How to use

1. Enter or paste your subtitle file.
2. Set the maximum reading speed.
3. Set the maximum characters per line.
4. Set the maximum lines per cue.
5. Set the minimum cue duration.
6. The result appears immediately — copy or download it.

## FAQ

### Why does reading speed matter more than character count?

Because a long line held for six seconds is comfortable while a short one flashed for half a second is not. Characters per second captures the relationship between the two, which is what a viewer actually experiences.

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