diff --git a/src/core/services/immersion-tracker/maintenance.ts b/src/core/services/immersion-tracker/maintenance.ts
index a20fc77..3c4034d 100644
--- a/src/core/services/immersion-tracker/maintenance.ts
+++ b/src/core/services/immersion-tracker/maintenance.ts
@@ -1,9 +1,6 @@
 import type { DatabaseSync } from './sqlite';
 import { nowMs } from './time';
-
-function toDbMs(ms: number | bigint): bigint {
-  return BigInt(Math.trunc(Number(ms)));
-}
+import { toDbMs } from './query-shared';
 
 const ROLLUP_STATE_KEY = 'last_rollup_sample_ms';
 const DAILY_MS = 86_400_000;
diff --git a/src/core/services/immersion-tracker/query-maintenance.ts b/src/core/services/immersion-tracker/query-maintenance.ts
index 420c69d..022386f 100644
--- a/src/core/services/immersion-tracker/query-maintenance.ts
+++ b/src/core/services/immersion-tracker/query-maintenance.ts
@@ -16,6 +16,7 @@ import {
   getAffectedWordIdsForSessions,
   getAffectedWordIdsForVideo,
   refreshLexicalAggregates,
+  toDbMs,
 } from './query-shared';
 
 type CleanupVocabularyRow = {
@@ -543,6 +544,3 @@ export function deleteVideo(db: DatabaseSync, videoId: number): void {
     throw error;
   }
 }
-function toDbMs(ms: number | bigint): bigint {
-  return BigInt(Math.trunc(Number(ms)));
-}
diff --git a/src/core/services/immersion-tracker/query-shared.ts b/src/core/services/immersion-tracker/query-shared.ts
index adab3d5..ffd59a5 100644
--- a/src/core/services/immersion-tracker/query-shared.ts
+++ b/src/core/services/immersion-tracker/query-shared.ts
@@ -270,3 +270,7 @@ export function deleteSessionsByIds(db: DatabaseSync, sessionIds: number[]): voi
   );
   db.prepare(`DELETE FROM imm_sessions WHERE session_id IN (${placeholders})`).run(...sessionIds);
 }
+
+export function toDbMs(ms: number | bigint): bigint {
+  return BigInt(Math.trunc(Number(ms)));
+}
diff --git a/src/core/services/immersion-tracker/session.ts b/src/core/services/immersion-tracker/session.ts
index e3f89e1..b0484f6 100644
--- a/src/core/services/immersion-tracker/session.ts
+++ b/src/core/services/immersion-tracker/session.ts
@@ -4,10 +4,7 @@ import { createInitialSessionState } from './reducer';
 import { nowMs } from './time';
 import { SESSION_STATUS_ACTIVE, SESSION_STATUS_ENDED } from './types';
 import type { SessionState } from './types';
-
-function toDbMs(ms: number | bigint): bigint {
-  return BigInt(Math.trunc(Number(ms)));
-}
+import { toDbMs } from './query-shared';
 
 export function startSessionRecord(
   db: DatabaseSync,
diff --git a/src/core/services/immersion-tracker/storage.ts b/src/core/services/immersion-tracker/storage.ts
index 3fa4174..ce8833c 100644
--- a/src/core/services/immersion-tracker/storage.ts
+++ b/src/core/services/immersion-tracker/storage.ts
@@ -4,10 +4,7 @@ import type { DatabaseSync } from './sqlite';
 import { nowMs } from './time';
 import { SCHEMA_VERSION } from './types';
 import type { QueuedWrite, VideoMetadata, YoutubeVideoMetadata } from './types';
-
-function toDbMs(ms: number | bigint): bigint {
-  return BigInt(Math.trunc(Number(ms)));
-}
+import { toDbMs } from './query-shared';
 
 export interface TrackerPreparedStatements {
   telemetryInsertStmt: ReturnType<DatabaseSync['prepare']>;