Lip Sync Animation: The Mouth Chart, the Timing and 4 Ways to Do It

Most guides to lip sync are tutorials for one program. This one starts with what works in every program: the mouth chart, how to break a line into sounds, and the timing that makes it look right. Then it compares the four ways to get it done, from drawing every mouth yourself to an app that does all of it.

What is lip sync animation?

Lip sync animation is moving a character’s mouth so it matches the words being spoken. The viewer should never have to wonder who’s talking, and the mouth should open and close with the voice.

It matters more on YouTube than people expect. Story videos are mostly dialogue, often watched on a phone, where a face fills the screen. A mouth that flaps at random, or stays still while a voice plays, breaks the story faster than plain drawing does. Animators don’t match every sound exactly, though. They match the ones the eye notices: the lips closing on M, B and P, the mouth opening wide on loud vowels, and the round “oo”.

What mouth shapes do you need? (The lip sync animation chart)

Six shapes cover most speech, and three more are optional. This set began at Hanna-Barbera for shows such as Scooby-Doo and The Flintstones, and it’s now a standard in 2D animation. Tools label the shapes with letters, and the letters are only names: “A” isn’t the sound A. Here’s the chart, with the letters the free tool Rhubarb Lip Sync uses:

Source: Rhubarb Lip Sync’s mouth shapes. Toon Boom Harmony’s mouth chart uses the same idea, with eight letters.

Draw each shape once for each character, from the front and from any other angle you’ll use. Shape C matters more than it looks: it’s the in-between when the mouth goes from closed to wide open, so the move from A through C to D should look smooth.

How do you do lip sync animation, step by step?

Whatever tool you use, the steps are the same:

1. Record the voice first. Animate to the finished audio, never the other way round. Read the line at the speed it’ll play in the video.
2. Break the line into sounds. Say it slowly and write down the sounds you hear, not the spelling. “Someday isn’t a day” is roughly S-UH-M-D-AY / I-Z-N-T / UH / D-AY.
3. Mark where each sound starts. In your editor or animation program, find the frame where each sound begins in the waveform. Loud vowels are the peaks; M, B and P sit just before a peak, where the line goes quiet.
4. Put a mouth shape on each sound. Use the chart. The closed shape on M, B and P is the one you must never miss.
5. Simplify. At 24 frames a second, many sounds last one or two frames. Drop the tiny ones and hold the shape for the bigger sound around them. A mouth that changes on every frame looks like it’s chattering.
6. Watch it at full speed, with sound. Fix what looks wrong, not what’s technically wrong.

How do you time the mouth to the voice?

Put each shape on the frame its sound starts, or a frame or two before, and never after. People see a mouth open slightly before they hear the sound, so a mouth that’s a touch early reads as in sync, while one that’s late looks like a dubbed film.

A few more rules make dialogue look natural:

• Close the mouth on M, B and P, even for a single frame. Viewers notice a “b” said through an open mouth.
• Don’t hit every sound. Match the stressed syllables and the shapes the lips make, and let the small sounds blend.
• Go back to rest between sentences. At the end of a line, the mouth should settle into the resting shape instead of freezing mid-word.
• Move more than the mouth. A small nod, a blink or the eyebrows on the stressed word make a talking face feel alive. A head that never moves makes even perfect lip sync look stiff.

What are the ways to do lip sync animation?

There are four, from the most work to the least:

Toon Boom’s auto lip sync doesn’t draw anything: your mouth drawings must already be in the character, named by their letter, and the tool only chooses which one shows on each frame (Harmony docs). Adobe planned to stop selling Animate on 1 March 2026, then reversed the decision two days later; it’s still available, but think twice before learning a program with no new features coming.

There are also AI tools that make a single photo or picture talk. They’re fine for one talking shot. For a story, where the same character speaks in a dozen shots from different angles, the mouth needs to be part of the character drawing, or it won’t match from shot to shot.

How do you lip sync a whole story video?

Each line needs three things: a voice, the right character on screen, and the mouth moving on that character. For a five-minute story with two characters, that’s often 40 to 70 lines, and doing them by hand is where most of the time goes. That’s why studios charge so much for dialogue (what animation costs per minute).

Plan it like this:

• Put the speaker on screen for each line. Cut to a close-up of whoever is talking. If you show someone else, show them reacting, and keep their mouth still.
• One voice per character. A different voice for each character, kept the same in every episode.
• No talking from behind. If a character has their back to us, cut away before they speak.

Drawn Films does all of this for you. Write or paste the story, check the script (who says each line is free to change), see a still of every shot, then press Make my video. Every character gets their own voice, and every line is spoken on screen by the character who says it, with the mouth moving to each word. There’s no narrator: the characters carry the story. The full guide to making animated story videos walks through the whole process, and this guide to short films shows how to write the lines.

What are the most common lip sync mistakes?

• The mouth is late. Slide all the shapes one or two frames earlier.
• The mouth chatters. Too many shapes. Hold the bigger sounds and drop the one-frame ones.
• M, B and P with the mouth open. Add the closed shape, even for one frame.
• The face is frozen. Add a blink, a nod or a brow on the stressed word.
• The wrong person’s mouth moves. In a two-shot, only the speaker talks. The listener reacts.

Questions people ask

How many mouth shapes do you need for lip sync?

Six is the usual minimum: closed (M, B, P), slightly open with teeth (most consonants), open, wide open, rounded and puckered. Add three more if you want: F and V, a long L, and a resting mouth.

What is a lip sync animation chart?

A sheet of the mouth shapes your character uses, each with a letter and the sounds it covers. You draw your character’s version of each shape once, then reuse them for every line.

Is there free lip sync animation software?

Yes. Rhubarb Lip Sync is free and open source: give it a voice recording and it works out which mouth shape goes where, for use in After Effects, Moho, OpenToonz and other tools. You still draw the mouths yourself.

Should the mouth move before or after the sound?

A frame or two before, or exactly on it, never after. A mouth that opens late looks like a badly dubbed film, while one that opens a touch early reads as in sync.

Can AI do lip sync for a cartoon?

Some tools make a still picture talk, which works for one shot. For a story with the same characters in many shots, you need the mouth drawn as part of the character, so it matches in every shot. Drawn Films does that for every line of your script.

Sources

1. Rhubarb Lip Sync, mouth shapes and how to run it (GitHub, checked 23 October 2026)
2. Toon Boom Harmony documentation, About lip-sync
3. Toon Boom Harmony documentation, Animating lip-sync
4. TechCrunch, Adobe cancels Animate shutdown and puts the app in maintenance mode (4 February 2026)