diff --git a/back/src/Kyoo.Abstractions/Controllers/IWatchStatusRepository.cs b/back/src/Kyoo.Abstractions/Controllers/IWatchStatusRepository.cs
index d9d9dcbf..e21806cf 100644
--- a/back/src/Kyoo.Abstractions/Controllers/IWatchStatusRepository.cs
+++ b/back/src/Kyoo.Abstractions/Controllers/IWatchStatusRepository.cs
@@ -48,7 +48,8 @@ public interface IWatchStatusRepository
 		Guid movieId,
 		Guid userId,
 		WatchStatus status,
-		int? watchedTime
+		int? watchedTime,
+		int? percent
 	);
 
 	Task DeleteMovieStatus(Guid movieId, Guid userId);
@@ -67,7 +68,8 @@ public interface IWatchStatusRepository
 		Guid episodeId,
 		Guid userId,
 		WatchStatus status,
-		int? watchedTime
+		int? watchedTime,
+		int? percent
 	);
 
 	Task DeleteEpisodeStatus(Guid episodeId, Guid userId);
diff --git a/back/src/Kyoo.Abstractions/Models/Resources/Episode.cs b/back/src/Kyoo.Abstractions/Models/Resources/Episode.cs
index 8cd63b1a..da363959 100644
--- a/back/src/Kyoo.Abstractions/Models/Resources/Episode.cs
+++ b/back/src/Kyoo.Abstractions/Models/Resources/Episode.cs
@@ -152,7 +152,7 @@ namespace Kyoo.Abstractions.Models
 		/// <summary>
 		/// How long is this episode? (in minutes)
 		/// </summary>
-		public int Runtime { get; set; }
+		public int? Runtime { get; set; }
 
 		/// <summary>
 		/// The release date of this episode. It can be null if unknown.
diff --git a/back/src/Kyoo.Abstractions/Models/Resources/Movie.cs b/back/src/Kyoo.Abstractions/Models/Resources/Movie.cs
index bfaf4bb5..f97c0f05 100644
--- a/back/src/Kyoo.Abstractions/Models/Resources/Movie.cs
+++ b/back/src/Kyoo.Abstractions/Models/Resources/Movie.cs
@@ -99,7 +99,7 @@ namespace Kyoo.Abstractions.Models
 		/// <summary>
 		/// How long is this movie? (in minutes)
 		/// </summary>
-		public int Runtime { get; set; }
+		public int? Runtime { get; set; }
 
 		/// <summary>
 		/// The date this movie aired.
diff --git a/back/src/Kyoo.Core/Controllers/Repositories/WatchStatusRepository.cs b/back/src/Kyoo.Core/Controllers/Repositories/WatchStatusRepository.cs
index aee11760..2bd896b2 100644
--- a/back/src/Kyoo.Core/Controllers/Repositories/WatchStatusRepository.cs
+++ b/back/src/Kyoo.Core/Controllers/Repositories/WatchStatusRepository.cs
@@ -236,14 +236,14 @@ public class WatchStatusRepository : IWatchStatusRepository
 		Guid movieId,
 		Guid userId,
 		WatchStatus status,
-		int? watchedTime
+		int? watchedTime,
+		int? percent
 	)
 	{
 		Movie movie = await _movies.Get(movieId);
-		int? percent =
-			watchedTime != null && movie.Runtime > 0
-				? (int)Math.Round(watchedTime.Value / (movie.Runtime * 60f) * 100f)
-				: null;
+
+		if (percent == null && watchedTime != null && movie.Runtime > 0)
+			percent = (int)Math.Round(watchedTime.Value / (movie.Runtime.Value * 60f) * 100f);
 
 		if (percent < MinWatchPercent)
 			return null;
@@ -259,6 +259,12 @@ public class WatchStatusRepository : IWatchStatusRepository
 				"Can't have a watched time if the status is not watching."
 			);
 
+		if (watchedTime.HasValue != percent.HasValue)
+			throw new ValidationException(
+				"Can't specify watched time without specifing percent (or vise-versa)."
+					+ "Percent could not be guessed since duration is unknown."
+			);
+
 		MovieWatchStatus ret =
 			new()
 			{
@@ -463,14 +469,14 @@ public class WatchStatusRepository : IWatchStatusRepository
 		Guid episodeId,
 		Guid userId,
 		WatchStatus status,
-		int? watchedTime
+		int? watchedTime,
+		int? percent
 	)
 	{
 		Episode episode = await _database.Episodes.FirstAsync(x => x.Id == episodeId);
-		int? percent =
-			watchedTime != null && episode.Runtime > 0
-				? (int)Math.Round(watchedTime.Value / (episode.Runtime * 60f) * 100f)
-				: null;
+
+		if (percent == null && watchedTime != null && episode.Runtime > 0)
+			percent = (int)Math.Round(watchedTime.Value / (episode.Runtime.Value * 60f) * 100f);
 
 		if (percent < MinWatchPercent)
 			return null;
@@ -486,6 +492,12 @@ public class WatchStatusRepository : IWatchStatusRepository
 				"Can't have a watched time if the status is not watching."
 			);
 
+		if (watchedTime.HasValue != percent.HasValue)
+			throw new ValidationException(
+				"Can't specify watched time without specifing percent (or vise-versa)."
+					+ "Percent could not be guessed since duration is unknown."
+			);
+
 		EpisodeWatchStatus ret =
 			new()
 			{
diff --git a/back/src/Kyoo.Core/Views/Resources/EpisodeApi.cs b/back/src/Kyoo.Core/Views/Resources/EpisodeApi.cs
index d2a73852..7a89df3c 100644
--- a/back/src/Kyoo.Core/Views/Resources/EpisodeApi.cs
+++ b/back/src/Kyoo.Core/Views/Resources/EpisodeApi.cs
@@ -147,7 +147,8 @@ namespace Kyoo.Core.Api
 		/// </remarks>
 		/// <param name="identifier">The ID or slug of the <see cref="Episode"/>.</param>
 		/// <param name="status">The new watch status.</param>
-		/// <param name="watchedTime">Where the user stopped watching.</param>
+		/// <param name="watchedTime">Where the user stopped watching (in seconds).</param>
+		/// <param name="percent">Where the user stopped watching (in percent).</param>
 		/// <returns>The newly set status.</returns>
 		/// <response code="200">The status has been set</response>
 		/// <response code="204">The status was not considered impactfull enough to be saved (less then 5% of watched for example).</response>
@@ -161,7 +162,8 @@ namespace Kyoo.Core.Api
 		public async Task<EpisodeWatchStatus?> SetWatchStatus(
 			Identifier identifier,
 			WatchStatus status,
-			int? watchedTime
+			int? watchedTime,
+			int? percent
 		)
 		{
 			Guid id = await identifier.Match(
@@ -170,7 +172,7 @@ namespace Kyoo.Core.Api
 			);
 			return await _libraryManager
 				.WatchStatus
-				.SetEpisodeStatus(id, User.GetIdOrThrow(), status, watchedTime);
+				.SetEpisodeStatus(id, User.GetIdOrThrow(), status, watchedTime, percent);
 		}
 
 		/// <summary>
diff --git a/back/src/Kyoo.Core/Views/Resources/MovieApi.cs b/back/src/Kyoo.Core/Views/Resources/MovieApi.cs
index db604836..627a7b93 100644
--- a/back/src/Kyoo.Core/Views/Resources/MovieApi.cs
+++ b/back/src/Kyoo.Core/Views/Resources/MovieApi.cs
@@ -196,6 +196,7 @@ namespace Kyoo.Core.Api
 		/// <param name="identifier">The ID or slug of the <see cref="Movie"/>.</param>
 		/// <param name="status">The new watch status.</param>
 		/// <param name="watchedTime">Where the user stopped watching.</param>
+		/// <param name="percent">Where the user stopped watching (in percent).</param>
 		/// <returns>The newly set status.</returns>
 		/// <response code="200">The status has been set</response>
 		/// <response code="204">The status was not considered impactfull enough to be saved (less then 5% of watched for example).</response>
@@ -210,7 +211,8 @@ namespace Kyoo.Core.Api
 		public async Task<MovieWatchStatus?> SetWatchStatus(
 			Identifier identifier,
 			WatchStatus status,
-			int? watchedTime
+			int? watchedTime,
+			int? percent
 		)
 		{
 			Guid id = await identifier.Match(
@@ -219,7 +221,7 @@ namespace Kyoo.Core.Api
 			);
 			return await _libraryManager
 				.WatchStatus
-				.SetMovieStatus(id, User.GetIdOrThrow(), status, watchedTime);
+				.SetMovieStatus(id, User.GetIdOrThrow(), status, watchedTime, percent);
 		}
 
 		/// <summary>
diff --git a/front/packages/models/src/resources/episode.base.ts b/front/packages/models/src/resources/episode.base.ts
index cd236f93..db2e86d2 100644
--- a/front/packages/models/src/resources/episode.base.ts
+++ b/front/packages/models/src/resources/episode.base.ts
@@ -49,7 +49,7 @@ export const BaseEpisodeP = withImages(
 		/**
 		 * How long is this movie? (in minutes).
 		 */
-		runtime: z.number().int(),
+		runtime: z.number().int().nullable(),
 		/**
 		 * The release date of this episode. It can be null if unknown.
 		 */
diff --git a/front/packages/models/src/resources/movie.ts b/front/packages/models/src/resources/movie.ts
index 481cb5dd..df425d6d 100644
--- a/front/packages/models/src/resources/movie.ts
+++ b/front/packages/models/src/resources/movie.ts
@@ -61,7 +61,7 @@ export const MovieP = withImages(
 		/**
 		 * How long is this movie? (in minutes).
 		 */
-		runtime: z.number().int(),
+		runtime: z.number().int().nullable(),
 		/**
 		 * The date this movie aired. It can also be null if this is unknown.
 		 */
diff --git a/front/packages/models/src/resources/watch-info.ts b/front/packages/models/src/resources/watch-info.ts
index b0b0e32f..a058b3d5 100644
--- a/front/packages/models/src/resources/watch-info.ts
+++ b/front/packages/models/src/resources/watch-info.ts
@@ -106,6 +106,10 @@ export const WatchInfoP = z.object({
 	 * The sha1 of the video file.
 	 */
 	sha: z.string(),
+	/**
+	 * The duration of the video (in seconds).
+	 */
+	length: z.number(),
 	/**
 	 * The internal path of the video file.
 	 */
diff --git a/front/packages/ui/src/details/episode.tsx b/front/packages/ui/src/details/episode.tsx
index 4a701bf5..5b4b10f7 100644
--- a/front/packages/ui/src/details/episode.tsx
+++ b/front/packages/ui/src/details/episode.tsx
@@ -57,7 +57,8 @@ export const episodeDisplayNumber = (
 	return def;
 };
 
-export const displayRuntime = (runtime: number) => {
+export const displayRuntime = (runtime: number | null) => {
+	if (!runtime) return null;
 	if (runtime < 60) return `${runtime}min`;
 	return `${Math.floor(runtime / 60)}h${runtime % 60}`;
 };
@@ -300,22 +301,19 @@ export const EpisodeLine = ({
 						)}
 					</Skeleton>
 					<View {...css({ flexDirection: "row", alignItems: "center" })}>
-						{isLoading ||
-							(runtime && (
-								<Skeleton>
-									{isLoading || (
-										<SubP>
-											{/* Source https://www.i18next.com/translation-function/formatting#datetime */}
-											{[
-												releaseDate ? t("{{val, datetime}}", { val: releaseDate }) : null,
-												displayRuntime(runtime),
-											]
-												.filter((item) => item != null)
-												.join(" · ")}
-										</SubP>
-									)}
-								</Skeleton>
-							))}
+						<Skeleton>
+							{isLoading || (
+								<SubP>
+									{/* Source https://www.i18next.com/translation-function/formatting#datetime */}
+									{[
+										releaseDate ? t("{{val, datetime}}", { val: releaseDate }) : null,
+										displayRuntime(runtime),
+									]
+										.filter((item) => item != null)
+										.join(" · ")}
+								</SubP>
+							)}
+						</Skeleton>
 						{slug && watchedStatus !== undefined && (
 							<EpisodesContext
 								slug={slug}
diff --git a/front/packages/ui/src/player/index.tsx b/front/packages/ui/src/player/index.tsx
index 039997a5..c870cb24 100644
--- a/front/packages/ui/src/player/index.tsx
+++ b/front/packages/ui/src/player/index.tsx
@@ -127,7 +127,7 @@ export const Player = ({ slug, type }: { slug: string; type: "episode" | "movie"
 				next={next}
 				previous={previous}
 			/>
-			{data && <WatchStatusObserver type={type} slug={data.slug} />}
+			{data && info && <WatchStatusObserver type={type} slug={data.slug} duration={info.length} />}
 			<View
 				{...css({
 					flexGrow: 1,
diff --git a/front/packages/ui/src/player/watch-status-observer.tsx b/front/packages/ui/src/player/watch-status-observer.tsx
index 804248ce..fd0b086e 100644
--- a/front/packages/ui/src/player/watch-status-observer.tsx
+++ b/front/packages/ui/src/player/watch-status-observer.tsx
@@ -28,9 +28,11 @@ import { playAtom, progressAtom } from "./state";
 export const WatchStatusObserver = ({
 	type,
 	slug,
+	duration,
 }: {
 	type: "episode" | "movie";
 	slug: string;
+	duration: number;
 }) => {
 	const account = useAccount();
 	const queryClient = useQueryClient();
@@ -47,9 +49,10 @@ export const WatchStatusObserver = ({
 				params: {
 					status: WatchStatusV.Watching,
 					watchedTime: Math.round(seconds),
+					percent: Math.round((seconds / duration) * 100),
 				},
 			}),
-		[_mutate, type, slug],
+		[_mutate, type, slug, duration],
 	);
 	const readProgress = useAtomCallback(
 		useCallback((get) => {