diff --git a/backend/src/modules/voice/voice.service.ts b/backend/src/modules/voice/voice.service.ts
index 209cee0..a5f9ee3 100644
--- a/backend/src/modules/voice/voice.service.ts
+++ b/backend/src/modules/voice/voice.service.ts
@@ -138,7 +138,7 @@ export class VoiceService {
 
     this.logTelemetry({
       locale: catalogLocale,
-      durationMs: dto.durationMs ?? null,
+      durationMs: dto.durationMs,
       elapsedMs: Date.now() - startedAt,
       asrCost,
       llmCost,
@@ -196,9 +196,20 @@ export class VoiceService {
     return profile;
   }
 
-  private assertWithinCap(durationMs?: number) {
+  /**
+   * Grace above the configured cap.
+   *
+   * The client auto-stops when elapsed >= maxMs, then measures the final length after the
+   * recorder has actually stopped — so a recording that runs to the cap always reports
+   * slightly over it. Without this tolerance the auto-stop would guarantee a rejection,
+   * discarding exactly the recording it was meant to save. The client still reports the
+   * true length, so telemetry stays honest.
+   */
+  private static readonly CAP_TOLERANCE_MS = 2_000;
+
+  private assertWithinCap(durationMs: number) {
     const max = this.voiceConfig.maxRecordingMs;
-    if (max != null && durationMs != null && durationMs > max) {
+    if (max != null && durationMs > max + VoiceService.CAP_TOLERANCE_MS) {
       throw new AppException(
         ErrorCode.VOICE_CLIP_TOO_LONG,
         HttpStatus.PAYLOAD_TOO_LARGE,
@@ -300,7 +311,7 @@ export class VoiceService {
    */
   private logTelemetry(input: {
     locale: string;
-    durationMs: number | null;
+    durationMs: number;
     elapsedMs: number;
     asrCost: number | null;
     llmCost: number | null;
diff --git a/frontend/src/lib/api/voice.ts b/frontend/src/lib/api/voice.ts
new file mode 100644
index 0000000..a9563c3
--- /dev/null
+++ b/frontend/src/lib/api/voice.ts
@@ -0,0 +1,28 @@
+import { apiClient } from './client';
+import type { VoiceAvailability, VoiceExtractionResult } from '@/types/voice';
+
+export interface ExtractVoicePayload {
+  /** Base64 audio, no data: prefix. */
+  audio: string;
+  format: string;
+  /** IANA zone — the server derives "today" from it for relative deadlines. */
+  timeZone: string;
+  durationMs: number;
+}
+
+export const voiceApi = {
+  availability: async (): Promise<{ success: boolean; data: VoiceAvailability }> => {
+    const response = await apiClient.get('/voice/availability');
+    return response.data;
+  },
+
+  extract: async (
+    payload: ExtractVoicePayload,
+    signal?: AbortSignal,
+  ): Promise<{ success: boolean; data: VoiceExtractionResult }> => {
+    // The signal is forwarded so cancelling closes the connection, which aborts the
+    // metered vendor call server-side rather than letting it settle unseen.
+    const response = await apiClient.post('/voice/extract', payload, { signal });
+    return response.data;
+  },
+};
diff --git a/frontend/src/lib/voice/audioFormat.ts b/frontend/src/lib/voice/audioFormat.ts
new file mode 100644
index 0000000..1199dc2
--- /dev/null
+++ b/frontend/src/lib/voice/audioFormat.ts
@@ -0,0 +1,62 @@
+/** Containers the backend accepts, in the order we prefer to record them. */
+const PREFERRED_MIME_TYPES = [
+  'audio/webm;codecs=opus',
+  'audio/webm',
+  'audio/mp4',
+  'audio/aac',
+  'audio/ogg;codecs=opus',
+  'audio/ogg',
+] as const;
+
+/**
+ * Pick a container this browser can record AND the backend accepts.
+ *
+ * Chrome and Android produce webm/opus; Safari and iPad produce mp4/aac. Both go to the
+ * vendor unmodified, so there is no transcode step — but the choice still has to be made
+ * at record time, and `isTypeSupported` is missing entirely on older Safari.
+ */
+export function pickRecordingMimeType(): string | null {
+  if (typeof MediaRecorder === 'undefined') return null;
+  if (typeof MediaRecorder.isTypeSupported !== 'function') {
+    // Safari <14.1 shipped MediaRecorder without the feature check; let it choose.
+    return '';
+  }
+  for (const type of PREFERRED_MIME_TYPES) {
+    if (MediaRecorder.isTypeSupported(type)) return type;
+  }
+  return null;
+}
+
+/** `audio/webm;codecs=opus` → `webm`, which is what the API's `format` field wants. */
+export function mimeTypeToFormat(mimeType: string): string {
+  const base = mimeType.split(';')[0]?.trim().toLowerCase() ?? '';
+  const subtype = base.startsWith('audio/') ? base.slice('audio/'.length) : base;
+  // Safari/iOS records `audio/mp4`, but the transcription endpoint's documented container
+  // list names m4a, not mp4. Same container; send the name the vendor documents, so iPad
+  // recordings do not fail while Chrome's webm works.
+  if (subtype === 'x-m4a' || subtype === 'm4a' || subtype === 'mp4') return 'm4a';
+  if (subtype === 'mpeg') return 'mp3';
+  return subtype || 'webm';
+}
+
+/** Blob → base64 without the `data:` prefix, which the API does not want. */
+export async function blobToBase64(blob: Blob): Promise<string> {
+  const buffer = await blob.arrayBuffer();
+  let binary = '';
+  const bytes = new Uint8Array(buffer);
+  // Chunked to avoid blowing the argument limit on a two-minute recording.
+  const chunkSize = 0x8000;
+  for (let i = 0; i < bytes.length; i += chunkSize) {
+    binary += String.fromCharCode(...bytes.subarray(i, i + chunkSize));
+  }
+  return btoa(binary);
+}
+
+export function isMediaRecorderSupported(): boolean {
+  return (
+    typeof window !== 'undefined' &&
+    typeof MediaRecorder !== 'undefined' &&
+    typeof navigator !== 'undefined' &&
+    Boolean(navigator.mediaDevices?.getUserMedia)
+  );
+}
diff --git a/frontend/src/lib/voice/useVoiceCapture.ts b/frontend/src/lib/voice/useVoiceCapture.ts
new file mode 100644
index 0000000..37574d7
--- /dev/null
+++ b/frontend/src/lib/voice/useVoiceCapture.ts
@@ -0,0 +1,253 @@
+'use client';
+
+import { useCallback, useEffect, useRef, useState } from 'react';
+import { voiceApi } from '@/lib/api/voice';
+import type { ApiError } from '@/types/api';
+import type { VoiceExtractionResult, VoicePhase } from '@/types/voice';
+import {
+  blobToBase64,
+  isMediaRecorderSupported,
+  mimeTypeToFormat,
+  pickRecordingMimeType,
+} from './audioFormat';
+
+export interface UseVoiceCaptureOptions {
+  /** null means uncapped; otherwise the recorder auto-stops here. */
+  maxMs: number | null;
+  onExtracted: (result: VoiceExtractionResult) => void;
+  onError: (error: unknown) => void;
+}
+
+export interface VoiceCaptureState {
+  phase: VoicePhase;
+  elapsedMs: number;
+  /** 0..1, for the level meter — proves the microphone is actually hearing something. */
+  level: number;
+  maxMs: number | null;
+  onStart: () => void;
+  onStop: () => void;
+  onCancel: () => void;
+}
+
+const LEVEL_POLL_MS = 100;
+
+/**
+ * Client-side failures must be ApiError-shaped or getUserFacingError cannot resolve them
+ * and every one renders the generic fallback, leaving errors.VOICE_MIC_DENIED dead.
+ */
+function clientError(code: string): ApiError {
+  return { statusCode: 0, code };
+}
+
+/**
+ * Microphone capture for treatment voice entry.
+ *
+ * Lives in lib/ rather than in the editor: TreatmentDetailsEditor stays presentational
+ * and receives only a `voice` prop, so MediaRecorder and the API call never enter ui/.
+ */
+export function useVoiceCapture({
+  maxMs,
+  onExtracted,
+  onError,
+}: UseVoiceCaptureOptions): VoiceCaptureState {
+  const [phase, setPhase] = useState<VoicePhase>('idle');
+  const [elapsedMs, setElapsedMs] = useState(0);
+  const [level, setLevel] = useState(0);
+
+  const recorderRef = useRef<MediaRecorder | null>(null);
+  const streamRef = useRef<MediaStream | null>(null);
+  const chunksRef = useRef<Blob[]>([]);
+  const startedAtRef = useRef(0);
+  const timerRef = useRef<ReturnType<typeof setInterval> | null>(null);
+  const audioContextRef = useRef<AudioContext | null>(null);
+  const abortRef = useRef<AbortController | null>(null);
+  /** Set when the user cancels, so the recorder's stop handler discards instead of sending. */
+  const cancelledRef = useRef(false);
+  /** getUserMedia is async; without this a permission granted after unmount leaks the mic. */
+  const mountedRef = useRef(true);
+
+  const teardown = useCallback(() => {
+    if (timerRef.current) {
+      clearInterval(timerRef.current);
+      timerRef.current = null;
+    }
+    streamRef.current?.getTracks().forEach((track) => track.stop());
+    streamRef.current = null;
+    void audioContextRef.current?.close().catch(() => undefined);
+    audioContextRef.current = null;
+    recorderRef.current = null;
+    setLevel(0);
+  }, []);
+
+  // Releasing the microphone on unmount matters: the browser shows a recording indicator
+  // for as long as the track is live, and an orphaned one looks like the app is listening.
+  useEffect(() => () => {
+    mountedRef.current = false;
+    cancelledRef.current = true;
+    abortRef.current?.abort();
+    try {
+      recorderRef.current?.stop();
+    } catch {
+      // already stopped
+    }
+    teardown();
+  }, [teardown]);
+
+  const send = useCallback(
+    async (blob: Blob, mimeType: string, durationMs: number) => {
+      setPhase('processing');
+      const controller = new AbortController();
+      abortRef.current = controller;
+      try {
+        const audio = await blobToBase64(blob);
+        const response = await voiceApi.extract(
+          {
+            audio,
+            format: mimeTypeToFormat(mimeType),
+            timeZone: Intl.DateTimeFormat().resolvedOptions().timeZone,
+            durationMs,
+          },
+          controller.signal,
+        );
+        if (cancelledRef.current) return;
+        onExtracted(response.data);
+      } catch (error) {
+        if (cancelledRef.current || controller.signal.aborted) return;
+        onError(error);
+      } finally {
+        abortRef.current = null;
+        setPhase('idle');
+        setElapsedMs(0);
+      }
+    },
+    [onExtracted, onError],
+  );
+
+  const stop = useCallback(() => {
+    try {
+      recorderRef.current?.stop();
+    } catch {
+      teardown();
+      setPhase('idle');
+    }
+  }, [teardown]);
+
+  const onStart = useCallback(() => {
+    if (phase !== 'idle') return;
+    if (!isMediaRecorderSupported()) {
+      onError(clientError('VOICE_MIC_DENIED'));
+      return;
+    }
+
+    cancelledRef.current = false;
+    void (async () => {
+      let stream: MediaStream;
+      try {
+        stream = await navigator.mediaDevices.getUserMedia({ audio: true });
+      } catch {
+        // Permission refused, or no input device. Never a server round-trip.
+        onError(clientError('VOICE_MIC_DENIED'));
+        return;
+      }
+
+      if (!mountedRef.current) {
+        // Permission resolved after the component went away — release it immediately
+        // rather than leaving the browser's recording indicator lit.
+        stream.getTracks().forEach((track) => track.stop());
+        return;
+      }
+
+      const mimeType = pickRecordingMimeType();
+      if (mimeType === null) {
+        stream.getTracks().forEach((track) => track.stop());
+        onError(clientError('VOICE_MIC_DENIED'));
+        return;
+      }
+
+      streamRef.current = stream;
+      chunksRef.current = [];
+      const recorder = new MediaRecorder(stream, mimeType ? { mimeType } : undefined);
+      recorderRef.current = recorder;
+
+      recorder.ondataavailable = (event) => {
+        if (event.data.size > 0) chunksRef.current.push(event.data);
+      };
+      recorder.onstop = () => {
+        const durationMs = Date.now() - startedAtRef.current;
+        const blob = new Blob(chunksRef.current, { type: recorder.mimeType || mimeType });
+        teardown();
+        if (cancelledRef.current || blob.size === 0) {
+          setPhase('idle');
+          setElapsedMs(0);
+          return;
+        }
+        void send(blob, recorder.mimeType || mimeType || 'audio/webm', durationMs);
+      };
+
+      attachLevelMeter(stream, audioContextRef, setLevel);
+
+      startedAtRef.current = Date.now();
+      recorder.start();
+      setPhase('recording');
+      setElapsedMs(0);
+
+      timerRef.current = setInterval(() => {
+        const elapsed = Date.now() - startedAtRef.current;
+        setElapsedMs(elapsed);
+        // Auto-stop proceeds to processing with what was captured; discarding two minutes
+        // of dictation because a timer expired would be the worst possible failure.
+        if (maxMs != null && elapsed >= maxMs) stop();
+      }, LEVEL_POLL_MS);
+    })();
+  }, [maxMs, onError, phase, send, stop, teardown]);
+
+  const onCancel = useCallback(() => {
+    cancelledRef.current = true;
+    // Aborting closes the connection, which aborts the vendor call server-side. It is
+    // metered per minute, so letting it settle costs money for a result nobody sees.
+    abortRef.current?.abort();
+    try {
+      recorderRef.current?.stop();
+    } catch {
+      // already stopped
+    }
+    teardown();
+    setPhase('idle');
+    setElapsedMs(0);
+  }, [teardown]);
+
+  return { phase, elapsedMs, level, maxMs, onStart, onStop: stop, onCancel };
+}
+
+/** Drives the level meter from the live stream; failure here must not stop recording. */
+function attachLevelMeter(
+  stream: MediaStream,
+  contextRef: React.MutableRefObject<AudioContext | null>,
+  setLevel: (value: number) => void,
+) {
+  try {
+    const AudioContextCtor =
+      window.AudioContext ?? (window as { webkitAudioContext?: typeof AudioContext }).webkitAudioContext;
+    if (!AudioContextCtor) return;
+
+    const context = new AudioContextCtor();
+    contextRef.current = context;
+    const source = context.createMediaStreamSource(stream);
+    const analyser = context.createAnalyser();
+    analyser.fftSize = 512;
+    source.connect(analyser);
+
+    const data = new Uint8Array(analyser.frequencyBinCount);
+    const tick = () => {
+      if (contextRef.current !== context || context.state === 'closed') return;
+      analyser.getByteTimeDomainData(data);
+      let peak = 0;
+      for (const sample of data) peak = Math.max(peak, Math.abs(sample - 128));
+      setLevel(Math.min(1, peak / 128));
+      requestAnimationFrame(tick);
+    };
+    requestAnimationFrame(tick);
+  } catch {
+    // A missing or blocked AudioContext costs the meter, not the recording.
+  }
+}
diff --git a/frontend/src/types/voice.ts b/frontend/src/types/voice.ts
new file mode 100644
index 0000000..3360839
--- /dev/null
+++ b/frontend/src/types/voice.ts
@@ -0,0 +1,58 @@
+import type { FdiToothId, ToothSelectionGroup } from '@/types/treatment';
+
+/** Mirrors the backend's ResolvedExtraction — values already resolved, plus what was not. */
+
+export type VoiceUnresolvedReason =
+  | 'not_permanent_tooth'
+  | 'position_out_of_range'
+  | 'malformed'
+  | 'span_not_same_arch'
+  | 'unknown_catalog_code'
+  | 'tooth_not_selected'
+  | 'invalid_date';
+
+export interface VoiceUnresolvedItem {
+  /** The transcript span that could not be resolved, so the clinician sees what was heard. */
+  spoken: string;
+  reason: VoiceUnresolvedReason;
+}
+
+export interface VoiceProsthesisResult {
+  byTooth: Record<string, string>;
+  /** False means the case cannot ship — every tooth needs a prosthesis type. */
+  complete: boolean;
+  missingTeeth: FdiToothId[];
+}
+
+export interface VoiceExtractionResult {
+  transcript: string;
+  treatmentType: string | null;
+  teeth: FdiToothId[];
+  toothSelectionGroups: ToothSelectionGroup[];
+  comment: string | null;
+  prosthesis: VoiceProsthesisResult | null;
+  labId: string | null;
+  /** When false, the lab row must not tick itself — the name only approximately matched. */
+  labMatchExact: boolean;
+  dueDate: string | null;
+  unresolved: VoiceUnresolvedItem[];
+}
+
+export interface VoiceAvailability {
+  enabled: boolean;
+  locales: string[];
+  /** null means uncapped. */
+  maxRecordingMs: number | null;
+}
+
+/** Which review rows the clinician ticked. */
+export interface VoiceApplySelection {
+  treatmentType: boolean;
+  teeth: boolean;
+  comment: boolean;
+  prosthesis: boolean;
+  lab: boolean;
+  dueDate: boolean;
+}
+
+export type VoicePhase = 'idle' | 'recording' | 'processing';