Netflix Subtitle Delivery Requirements — Complete Guide

File Formats, Reading Speed, Character Limits, SDH, Timing & TTML Technical Specifications — Updated 2026

Delivering subtitles to Netflix requires meeting one of the most precise and comprehensive timed text style guides in the streaming industry. Netflix’s subtitle requirements cover file format, reading speed, character limits per line, timing precision relative to shot changes, SDH specifications, translator credits, glyph restrictions, and TTML technical formatting — and files that fail to meet these specifications are rejected before they reach a human reviewer.

This guide covers every Netflix subtitle delivery requirement you need to know before submitting timed text to Netflix for the first time — or before conforming existing subtitle files to Netflix specifications. For the most current version of Netflix’s requirements, always refer to the Netflix Partner Help Center at partnerhelp.netflixstudios.com alongside this guide.

File Format Requirements

Netflix requires all subtitle and SDH files for all languages to be delivered in TTML1 format — with the file extension .xml or .ttml. This applies to every language except Japanese, which must be delivered in IMSC1.1 format with the .xml extension.

The TTML format requirement applies to both subtitles and SDH tracks. SRT, VTT, SCC, and other subtitle formats are not accepted for Netflix deliveries unless you have discussed an exception with your Netflix representative. If you are conforming existing subtitle files from another platform for Netflix delivery, they must be converted to TTML1 before submission.

Key requirement: TTML1 (.xml or .ttml) for all languages. Japanese: IMSC1.1 (.xml) only.

Reading Speed Requirements

Netflix’s reading speed standard for English subtitles is a maximum of 20 characters per second for adult content and 17 characters per second for children’s content. Reading speed is measured in characters per second and determines how long each subtitle event must remain on screen to be readable at a comfortable pace.

Reading speed is one of the most common reasons subtitle files are rejected by Netflix QC. Files where subtitle events are timed too quickly — displaying more characters per second than the maximum — require manual adjustment of event timing before resubmission.  

Adult content: 20 characters per second maximum. Children’s content: 17 characters per second maximum.

Character Limits Per Line

Netflix specifies a maximum of 42 characters per line for most Latin alphabet languages. Text should always be kept to one line unless it exceeds this character limit — Netflix prefers single-line subtitles wherever possible.

When text must break across two lines, Netflix requires specific line-break conventions to maintain readability. The maximum is two lines per subtitle event. Line breaks should divide the text at a natural linguistic break — preferably between clauses or at a conjunction — rather than breaking mid-phrase.

Never break a line between:

• An article and the noun it modifies
• A preposition and its object
• Parts of a compound verb
• A conjunction and the clause it introduces

Maximum: 42 characters per line. Maximum: 2 lines per subtitle event. Prefer 1 line wherever possible.

Duration Requirements

Each subtitle event must meet the following duration requirements:

• Minimum duration: 5/6 of a second per subtitle event — equivalent to 20 frames at 24fps. Subtitle events shorter than this minimum are rejected.
• Maximum duration: 7 seconds per subtitle event. Events longer than 7 seconds must be split.

These duration requirements exist to ensure subtitles display long enough to be read comfortably while not remaining on screen so long that they become distracting or visually stale.

Minimum: 5/6 second (20 frames at 24fps). Maximum: 7 seconds. Events outside this range are automatically rejected.

Frame Gap Requirements

A minimum gap of two frames must exist between consecutive subtitle events, regardless of frame rate. This two-frame gap prevents subtitle events from appearing to flash or flicker when one event ends and the next begins immediately.

Frame gap requirements interact with shot change timing requirements — when a shot change falls within a gap between subtitle events, additional timing adjustments may be required to ensure subtitles do not cross the shot boundary.  

Minimum 2-frame gap between all consecutive subtitle events. This applies regardless of frame rate.

Shot Change Timing Requirements

Netflix requires subtitles to be timed in relation to shot changes — one of the most technically demanding aspects of Netflix subtitle delivery. The general principle is that subtitles should not cross shot changes where possible, as crossing a cut disrupts the visual flow of the viewing experience.

The timing zones are:

• Green zone (8–11 frames before or after a shot change) — subtitle in-times or out-times falling in this zone should be moved to at least 12 frames from the shot change
• Red zone (7 frames or fewer before or after a shot change) — subtitle in-times falling in this zone should be moved to the shot change itself. Out-times falling in this zone should be moved to the shot change, respecting the two-frame gap

When there is one subtitle before and one after a shot change, the post-change subtitle should start on the shot change and the pre-change subtitle should end at least two frames before it.

Subtitles within 7 frames of a shot change (red zone) must be moved to the cut point. Subtitles 8-11 frames from a shot change (green zone) must be moved to at least 12 frames from the cut.

Positioning Requirements

All subtitles must be center-justified and placed at either the top or bottom of the screen. Bottom placement is standard — top placement is used when on-screen text at the bottom of the frame would be obscured by the subtitle. Positional data in TTML files must be expressed in generic terms using tts:textAlign and tts:displayAlign with static values for tts:extent and tts:origin. Percentage values must be used — never pixel values. The tts:fontSize must be defined as 100%. Netflix rejects files that use absolute pixel values for positioning.

Center justified, top or bottom of screen. Use percentage values only — never pixel values in TTML positioning.

SDH — Subtitles for the Deaf and Hard of Hearing

SDH files must include all audio information relevant to the viewing experience — spoken dialogue, speaker identification for off-screen or unclear speakers, relevant sound effects described in square brackets, and music identifiers where applicable. SDH transcription should be as close to the original dialogue as possible — paraphrasing is not permitted.

Slang, dialect, and other non-standard speech features must be transcribed accurately and authentically. Sound effects should be described in square brackets in present tense — [door slams] not [door slamming]. Music should be identified with the song title and artist name where available — referenced from Netflix-provided materials such as end credits rather than from external sources. Translator credits for SDH files should only be included if translating from the original language — not when transcribing the original or dubbed audio. For broadcast compliance, see our closed captioning services — FCC, ADA, and CVAA compliant from our NYC studio.

SDH must include all audio information. No paraphrasing. Sound effects in square brackets, present tense. Translator credits only when translating — not when transcribing.

Glyph List Requirements

Netflix maintains a proprietary Glyph List specifying every character and text element that may appear in subtitle files. Only characters from the Netflix Glyph List may be used — non-standard characters, unsupported punctuation marks, or characters not included in the approved list will cause file rejection. The Glyph List is available through the Netflix Partner Help Center. If you are producing multilingual subtitle files for Netflix, each language’s character set must be verified against the Glyph List before delivery — languages with extended character sets such as Arabic, Chinese, Korean, and Japanese have specific glyph requirements beyond the standard Latin alphabet list.

Only characters from the Netflix Glyph List may be used. Verify against the list before delivering multilingual files — especially Arabic, Chinese, Korean, and Japanese.

Ellipsis and Punctuation Requirements

Netflix requires the single smart ellipsis character (Unicode U+2026) — not three consecutive periods. This distinction matters for TTML file validation — files using three periods instead of the single ellipsis character fail technical QC.

Ellipses are used to indicate a pause of two seconds or more, or when dialogue trails off. They are not used when an ongoing sentence is split between two consecutive subtitle events with a pause shorter than two seconds — in that case the sentence simply continues without punctuation across the subtitle break.

Double hyphens are used in US English subtitle files to indicate an abrupt interruption. Note that UK English Netflix guidelines do not permit double hyphens and use ellipses instead — the correct punctuation convention depends on the target language style guide.

Always use Unicode U+2026 (single smart ellipsis) — never three periods. US English uses double hyphens for interruptions. UK English uses ellipses instead.

Consistency Requirements — KNP Tables

For episodic content and series, Netflix requires Key Name and Phrase (KNP) tables and formality tables to be created and used for translation — ensuring consistency in character names, title cards, and key terminology across all episodes and seasons. These consistency documents must be provided to Netflix upon delivery of timed text material for QC purposes.

Translations for Netflix Originals title cards must be included in full in both the subtitle stream and forced subtitle stream. Currency mentioned in dialogue must remain in its original currency — do not convert currency values in subtitle files.

KNP and formality tables required for all episodic content. Provide to Netflix on delivery. Do not convert currency values in subtitle files.

Forced Narratives

Netflix requires final video to be delivered without burned-in subtitles. Where the original content contains on-screen text in a different language from the subtitle file — such as plot-pertinent foreign-language signage, title cards, or on-screen text — a Forced Narrative file must be delivered separately using Netflix’s provided template, with the text translated into the target language with corresponding in and out timecodes.

Forced Narrative files must credit the subtitle translator unless the file contains only Netflix-provided translations for episode titles and approved Netflix Original Credits translations.

Never deliver burned-in subtitles. All plot-pertinent on-screen foreign-language text must be delivered as a separate Forced Narrative file using Netflix’s template.

TTML Technical Specifications

All TTML files created for Netflix must meet the following technical specifications:

• Use percentage values only — never pixel values
• Use tts:textAlign and tts:displayAlign for positioning
• Use static values for tts:extent and tts:origin
• Define tts:fontSize as 100% — never use pixel values
• 23.976fps content — use SMPTE 24 timecode or 23.976 Media-Time — specify using ttp:timeBase
• 59.94fps and 29.97fps content — use drop-frame 29.97 timecode using ttp:dropMode
• IMSC1.1 documents must only use Media-Time — ttp:dropMode does not apply
• Japanese subtitles must be delivered in IMSC1.1 format (.xml) — not TTML1

Quick Reference — Netflix Subtitle Delivery Specifications

Requirement	Specification
File format	TTML1 (.xml or .ttml) — all languages except Japanese
Japanese format	IMSC1.1 (.xml)
Maximum characters per line	42 characters
Maximum lines per event	2 lines
Minimum event duration	5/6 second (20 frames at 24fps)
Maximum event duration	7 seconds
Frame gap between events	2 frames minimum
Reading speed — adult content	20 characters per second maximum
Reading speed — children’s content	17 characters per second maximum
Positioning	Center justified, top or bottom of screen
Positioning values	Percentage only — no pixel values
Ellipsis character	Unicode U+2026 — not three periods
Glyph restriction	Netflix Glyph List only
Translator credits	Required for episodic and features — not marketing assets
Burned-in subtitles	Not permitted in final video delivery

Working with a Netflix Preferred Vendor

Netflix strongly encourages content producers to work with Netflix Preferred Vendors (NPVs) for subtitle and timed text delivery. NPVs are subtitling and localization companies that have been vetted by Netflix for quality, technical compliance, and delivery reliability. Working with an NPV means your subtitle files are reviewed against Netflix’s current specifications before submission — significantly reducing the risk of rejection and redelivery delays that can push back your platform release date.

Gotham Lab — Netflix Subtitle Delivery from New York City

Gotham Lab provides Netflix-compliant subtitle delivery for feature films, documentaries, episodic content, and short-form programming in 50+ languages — meeting all technical specifications outlined in this guide including TTML1 format, reading speed compliance, shot change timing, SDH production, and CCSL creation. Contact us for a free consultation on your Netflix delivery project — we respond within one business day. Need a complete localization package beyond subtitles? Our movie localization services cover subtitling, dubbing, voice-over, and CCSL for Netflix and all major streaming platforms.