diff --git a/client/components/layout/NavPill.jsx b/client/components/layout/NavPill.jsx
index 8ca4c7a..6aa98cb 100644
--- a/client/components/layout/NavPill.jsx
+++ b/client/components/layout/NavPill.jsx
@@ -1,8 +1,9 @@
 import React, { useMemo } from 'react';
 import { NavLink } from 'react-router-dom';
 import { cn } from '@/lib/utils';
+import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip';
 
-export const NavPill = React.memo(function NavPill({ item, onNavigate, badge }) {
+export const NavPill = React.memo(function NavPill({ item, onNavigate, badge, badgeNames = [] }) {
   const Icon = useMemo(() => item.icon, [item.icon]);
   const to = useMemo(() => item.to, [item.to]);
   const end = useMemo(() => item.end, [item.end]);
@@ -24,9 +25,24 @@ export const NavPill = React.memo(function NavPill({ item, onNavigate, badge })
       <Icon className="h-4 w-4" />
       <span>{label}</span>
       {badge > 0 && (
-        <span className="ml-0.5 flex h-4 min-w-[1rem] items-center justify-center rounded-full bg-rose-500 px-1 text-[10px] font-bold leading-none text-white">
-          {badge > 99 ? '99+' : badge}
-        </span>
+        <TooltipProvider delayDuration={300}>
+          <Tooltip>
+            <TooltipTrigger asChild>
+              <span className="ml-0.5 flex h-4 min-w-[1rem] items-center justify-center rounded-full bg-rose-500 px-1 text-[10px] font-bold leading-none text-white">
+                {badge > 99 ? '99+' : badge}
+              </span>
+            </TooltipTrigger>
+            <TooltipContent side="top" className="max-w-[200px]">
+              <p className="font-semibold mb-1">{badge} past due</p>
+              {badgeNames.slice(0, 5).map(name => (
+                <p key={name} className="text-xs opacity-80">· {name}</p>
+              ))}
+              {badgeNames.length > 5 && (
+                <p className="text-xs opacity-60">+{badgeNames.length - 5} more</p>
+              )}
+            </TooltipContent>
+          </Tooltip>
+        </TooltipProvider>
       )}
     </NavLink>
   );
diff --git a/client/components/layout/Sidebar.jsx b/client/components/layout/Sidebar.jsx
index 8b27447..4df2744 100644
--- a/client/components/layout/Sidebar.jsx
+++ b/client/components/layout/Sidebar.jsx
@@ -10,6 +10,7 @@ import { useAuth } from '@/hooks/useAuth';
 import { useOverdueCount } from '@/hooks/useQueries';
 import { ThemeToggle } from '@/components/ui/theme-toggle';
 import { Button } from '@/components/ui/button';
+import { Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@/components/ui/tooltip';
 import {
   DropdownMenu,
   DropdownMenuContent,
@@ -44,7 +45,7 @@ const trackerItems = [
   { to: '/payoff',   icon: Calculator,  label: 'Payoff' },
 ];
 
-function TrackerMenu({ onNavigate, badge }) {
+function TrackerMenu({ onNavigate, badge, badgeNames = [] }) {
   const location = useLocation();
   const navigate = useNavigate();
   const isTrackerActive = useMemo(() => trackerItems.some(item => (
@@ -68,9 +69,24 @@ function TrackerMenu({ onNavigate, badge }) {
           <LayoutGrid className="h-4 w-4" />
           Tracker
           {badge > 0 && (
-            <span className="flex h-4 min-w-[1rem] items-center justify-center rounded-full bg-rose-500 px-1 text-[10px] font-bold leading-none text-white">
-              {badge > 99 ? '99+' : badge}
-            </span>
+            <TooltipProvider delayDuration={300}>
+              <Tooltip>
+                <TooltipTrigger asChild>
+                  <span className="flex h-4 min-w-[1rem] items-center justify-center rounded-full bg-rose-500 px-1 text-[10px] font-bold leading-none text-white">
+                    {badge > 99 ? '99+' : badge}
+                  </span>
+                </TooltipTrigger>
+                <TooltipContent side="right" className="max-w-[200px]">
+                  <p className="font-semibold mb-1">{badge} past due</p>
+                  {badgeNames.slice(0, 5).map(name => (
+                    <p key={name} className="text-xs opacity-80">· {name}</p>
+                  ))}
+                  {badgeNames.length > 5 && (
+                    <p className="text-xs opacity-60">+{badgeNames.length - 5} more</p>
+                  )}
+                </TooltipContent>
+              </Tooltip>
+            </TooltipProvider>
           )}
           <ChevronDown className="h-3.5 w-3.5 opacity-75" />
         </button>
@@ -178,6 +194,7 @@ export default function Sidebar({ adminMode = false }) {
   const items = useMemo(() => adminMode ? adminNavItems : userNavItems, [adminMode]);
   const { data: overdueData } = useOverdueCount();
   const overdueCount = (!adminMode && overdueData?.count) ? overdueData.count : 0;
+  const overdueNames = (!adminMode && overdueData?.names) ? overdueData.names : [];
 
   return (
     <header className="sticky top-0 z-40 border-b border-border/80 bg-card/95 shadow-sm shadow-foreground/10 backdrop-blur-md supports-[backdrop-filter]:bg-card/90">
@@ -185,7 +202,7 @@ export default function Sidebar({ adminMode = false }) {
         <BrandBlock adminMode={adminMode} />
 
         <nav className="hidden items-center gap-1 lg:flex">
-          {!adminMode && <TrackerMenu badge={overdueCount} />}
+          {!adminMode && <TrackerMenu badge={overdueCount} badgeNames={overdueNames} />}
           {items.map(item => (
             <NavPill key={item.to} item={item} />
           ))}
@@ -232,6 +249,7 @@ export default function Sidebar({ adminMode = false }) {
                 item={item}
                 onNavigate={() => setMobileOpen(false)}
                 badge={item.to === '/' ? overdueCount : undefined}
+                badgeNames={item.to === '/' ? overdueNames : undefined}
               />
             ))}
             {items.map(item => (
diff --git a/services/trackerService.js b/services/trackerService.js
index 665b298..b9ef7a8 100644
--- a/services/trackerService.js
+++ b/services/trackerService.js
@@ -537,21 +537,24 @@ function getOverdueCount(userId, now = new Date()) {
   `).all(year, month, rangeStart, rangeEnd, userId);
 
   let count = 0;
+  const overdueNames = [];
   for (const bill of bills) {
     if (bill.is_skipped) continue;
     if (bill.snoozed_until && bill.snoozed_until > todayStr) continue;
     if (bill.autopay_enabled && bill.autodraft_status === 'assumed_paid') continue;
 
     const dueDate = resolveDueDate(bill, year, month);
-    if (!dueDate || dueDate > todayStr) continue;
+    // Use >= so bills due TODAY are not counted as overdue — only strictly past dates
+    if (!dueDate || dueDate >= todayStr) continue;
 
     const threshold = bill.actual_amount != null ? bill.actual_amount : bill.expected_amount;
     if (threshold > 0 && bill.total_paid >= threshold) continue;
 
     count++;
+    overdueNames.push(bill.name);
   }
 
-  return { count, month, year, today: todayStr };
+  return { count, names: overdueNames, month, year, today: todayStr };
 }
 
 module.exports = {