diff --git a/extension/src/popup/components/devices.ts b/extension/src/popup/components/devices.ts
index c10956f..5b7c0d4 100644
--- a/extension/src/popup/components/devices.ts
+++ b/extension/src/popup/components/devices.ts
@@ -2,6 +2,7 @@
 
 import { setState, sendMessage, navigate, escapeHtml } from '../../shared/state';
 import type { Device } from '../../shared/types';
+import { relativeTime } from '../../shared/relative-time';
 
 interface RevokedEntry {
   name: string;
@@ -10,16 +11,6 @@ interface RevokedEntry {
   revoked_by: string;
 }
 
-function relativeTime(unixSec: number): string {
-  const now = Math.floor(Date.now() / 1000);
-  const diff = now - unixSec;
-  if (diff < 60)    return 'just now';
-  if (diff < 3600)  return `${Math.floor(diff / 60)}m ago`;
-  if (diff < 86400) return `${Math.floor(diff / 3600)}h ago`;
-  if (diff < 2592000) return `${Math.floor(diff / 86400)}d ago`;
-  return `${Math.floor(diff / 2592000)}mo ago`;
-}
-
 function detectDefaultDeviceName(): string {
   const ua = navigator.userAgent ?? '';
   const platform = (navigator.platform ?? '').toLowerCase();
diff --git a/extension/src/popup/components/field-history.ts b/extension/src/popup/components/field-history.ts
index 1edf1f2..8cf1454 100644
--- a/extension/src/popup/components/field-history.ts
+++ b/extension/src/popup/components/field-history.ts
@@ -3,19 +3,9 @@
 import { getState, setState, sendMessage, navigate, escapeHtml } from '../../shared/state';
 import { colorizePassword } from '../../shared/password-coloring';
 import type { FieldHistoryView } from '../../shared/types';
+import { relativeTime } from '../../shared/relative-time';
 import { GLYPH_COPY } from '../../shared/glyphs';
 
-function relativeTime(unixSec: number): string {
-  const now = Math.floor(Date.now() / 1000);
-  const diff = now - unixSec;
-  if (diff < 60)    return 'just now';
-  if (diff < 3600)  return `${Math.floor(diff / 60)}m ago`;
-  if (diff < 86400) return `${Math.floor(diff / 3600)}h ago`;
-  if (diff < 604800) return `${Math.floor(diff / 86400)}d ago`;
-  if (diff < 2592000) return `${Math.floor(diff / 604800)}w ago`;
-  return `${Math.floor(diff / 2592000)}mo ago`;
-}
-
 const revealedSet = new Set<string>();
 
 // Map from entry key → plaintext value; populated on each render so we never
diff --git a/extension/src/popup/components/settings-vault.ts b/extension/src/popup/components/settings-vault.ts
index 288c032..14749c6 100644
--- a/extension/src/popup/components/settings-vault.ts
+++ b/extension/src/popup/components/settings-vault.ts
@@ -6,6 +6,7 @@ import { getState, setState, sendMessage, navigate, escapeHtml, openVaultTab } f
 import type {
   VaultSettings, TrashRetention, HistoryRetention, GeneratorRequest,
 } from '../../shared/types';
+import { relativeTime } from '../../shared/relative-time';
 import { openGeneratorPanel, closeGeneratorPanel, isGeneratorPanelOpen } from './generator-panel';
 import { GLYPH_NEXT } from '../../shared/glyphs';
 
@@ -65,17 +66,6 @@ function generatorSummary(req: GeneratorRequest): string {
   return `BIP39, ${req.word_count} words, "${req.separator}" separator, ${req.capitalization}`;
 }
 
-// --- Time formatting ---
-
-function relativeTime(unixSec: number): string {
-  const now = Math.floor(Date.now() / 1000);
-  const diff = now - unixSec;
-  if (diff < 60)    return 'just now';
-  if (diff < 3600)  return `${Math.floor(diff / 60)}m ago`;
-  if (diff < 86400) return `${Math.floor(diff / 3600)}h ago`;
-  return `${Math.floor(diff / 86400)}d ago`;
-}
-
 // --- Render ---
 
 export function renderVaultSettings(app: HTMLElement): void {
diff --git a/extension/src/popup/components/trash.ts b/extension/src/popup/components/trash.ts
index 27c32a5..9c26383 100644
--- a/extension/src/popup/components/trash.ts
+++ b/extension/src/popup/components/trash.ts
@@ -2,6 +2,7 @@
 
 import { getState, setState, sendMessage, navigate, escapeHtml } from '../../shared/state';
 import type { ItemId, ManifestEntry, VaultSettings } from '../../shared/types';
+import { relativeTime, daysUntilPurge } from '../../shared/relative-time';
 import {
   GLYPH_TYPE_LOGIN, GLYPH_TYPE_SECURE_NOTE, GLYPH_TYPE_IDENTITY, GLYPH_TYPE_CARD,
   GLYPH_TYPE_KEY, GLYPH_TYPE_DOCUMENT, GLYPH_TYPE_TOTP,
@@ -17,21 +18,6 @@ const TYPE_ICONS: Record<string, string> = {
   totp: GLYPH_TYPE_TOTP,
 };
 
-function relativeTime(unixSec: number): string {
-  const now = Math.floor(Date.now() / 1000);
-  const diff = now - unixSec;
-  if (diff < 60)    return 'just now';
-  if (diff < 3600)  return `${Math.floor(diff / 60)}m ago`;
-  if (diff < 86400) return `${Math.floor(diff / 3600)}h ago`;
-  return `${Math.floor(diff / 86400)}d ago`;
-}
-
-function daysUntilPurge(trashedAt: number, retention: VaultSettings['trash_retention']): number | null {
-  if (retention.kind === 'forever') return null;
-  const trashedDaysAgo = Math.floor((Date.now() / 1000 - trashedAt) / 86400);
-  return Math.max(0, retention.value - trashedDaysAgo);
-}
-
 export function teardown(): void {
   // No cleanup needed
 }
diff --git a/extension/src/vault/vault.ts b/extension/src/vault/vault.ts
index 2f8f0a0..4ef0196 100644
--- a/extension/src/vault/vault.ts
+++ b/extension/src/vault/vault.ts
@@ -10,6 +10,7 @@ import type {
 } from '../shared/types';
 import { registerHost } from '../shared/state';
 import { lookupErrorCopy, type ErrorCta } from '../shared/error-copy';
+import { relativeTime } from '../shared/relative-time';
 import {
   GLYPH_TRASH, GLYPH_DEVICES, GLYPH_SETTINGS, GLYPH_LOCK,
   GLYPH_TYPE_LOGIN, GLYPH_TYPE_SECURE_NOTE, GLYPH_TYPE_TOTP,
@@ -122,14 +123,6 @@ function typeLabel(t: ItemType): string {
   return labels[t];
 }
 
-function relativeTime(unixSec: number): string {
-  const diffS = Math.floor(Date.now() / 1000) - unixSec;
-  if (diffS < 60) return 'just now';
-  if (diffS < 3600) return `${Math.floor(diffS / 60)}m ago`;
-  if (diffS < 86400) return `${Math.floor(diffS / 3600)}h ago`;
-  return `${Math.floor(diffS / 86400)}d ago`;
-}
-
 // ---------------------------------------------------------------------------
 // Hash routing
 // ---------------------------------------------------------------------------