diff --git a/backend/src/lib/cost-calc.js b/backend/src/lib/cost-calc.js
index 67c5e2c..d6a4895 100644
--- a/backend/src/lib/cost-calc.js
+++ b/backend/src/lib/cost-calc.js
@@ -167,9 +167,19 @@ export async function getTrailingDailyRate(meterId, windowDays) {
   windowStart.setDate(windowStart.getDate() - windowDays)
   const windowStartStr = windowStart.toISOString().slice(0, 10)
 
-  const before = await readingOnOrBefore(meterId, windowStartStr)
+  let before = await readingOnOrBefore(meterId, windowStartStr)
   if (!before || before.reading_date >= latest.reading_date) {
-    return { daily_rate: null, latest }
+    // Nothing old enough to fill the window (readings are sparse) — fall back
+    // to the average between the last two readings so the estimate carries
+    // forward instead of dropping to zero until a new reading is added.
+    const { rows } = await pool.query(
+      `SELECT reading_value, reading_date FROM readings
+       WHERE meter_id = $1 AND reading_date < $2
+       ORDER BY reading_date DESC, id DESC LIMIT 1`,
+      [meterId, latest.reading_date]
+    )
+    before = rows[0] || null
+    if (!before) return { daily_rate: null, latest }
   }
   const days = daysBetween(before.reading_date, latest.reading_date)
   if (days <= 0) return { daily_rate: null, latest }
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 914608c..0a25c6e 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -7,6 +7,7 @@ import Layout from './components/Layout'
 import Meters from './pages/Meters'
 import MeterDetail from './pages/MeterDetail'
 import Tariffs from './pages/Tariffs'
+import AddReading from './pages/AddReading'
 import Readings from './pages/Readings'
 import Reports from './pages/Reports'
 import Estimates from './pages/Estimates'
@@ -20,7 +21,7 @@ export default function App() {
         <AuthGate>
           <Layout>
             <Routes>
-              <Route path="/" element={<Navigate to="/meters" replace />} />
+              <Route path="/" element={<AddReading />} />
               <Route path="/meters" element={<Meters />} />
               <Route path="/meters/:id" element={<MeterDetail />} />
               <Route path="/readings" element={<Readings />} />
diff --git a/frontend/src/components/Layout.tsx b/frontend/src/components/Layout.tsx
index 98faa80..bf3e259 100644
--- a/frontend/src/components/Layout.tsx
+++ b/frontend/src/components/Layout.tsx
@@ -1,12 +1,13 @@
 import { useState, useEffect } from 'react'
 import { NavLink, useLocation } from 'react-router-dom'
-import { Zap, Gauge, Receipt, BarChart3, TrendingUp, Settings, Menu, LogOut } from 'lucide-react'
+import { Zap, PlusCircle, Gauge, Receipt, BarChart3, TrendingUp, Settings, Menu, LogOut } from 'lucide-react'
 import { useAuth } from './AuthGate'
 import { can } from '../types'
 
 const ICON_PROPS = { size: 16, strokeWidth: 1.75 }
 
 const NAV = [
+  { to: '/',          label: 'Add reading', icon: PlusCircle, cap: 'readings', end: true },
   { to: '/meters',    label: 'Meters',    icon: Gauge,      cap: 'meters' },
   { to: '/readings',  label: 'Readings',  icon: Zap,        cap: 'readings' },
   { to: '/tariffs',   label: 'Tariffs',   icon: Receipt,    cap: 'tariffs' },
@@ -37,7 +38,7 @@ export default function Layout({ children }: { children: React.ReactNode }) {
         </div>
         <nav className="sidebar-nav">
           {items.map(({ to, label, icon: Icon }) => (
-            <NavLink key={to} to={to} className={({ isActive }) => isActive ? 'active' : ''}>
+            <NavLink key={to} to={to} end={to === '/'} className={({ isActive }) => isActive ? 'active' : ''}>
               <Icon {...ICON_PROPS} />
               {label}
             </NavLink>
diff --git a/frontend/src/components/PhotoPicker.tsx b/frontend/src/components/PhotoPicker.tsx
new file mode 100644
index 0000000..f6c451e
--- /dev/null
+++ b/frontend/src/components/PhotoPicker.tsx
@@ -0,0 +1,38 @@
+import { useRef } from 'react'
+import { Camera, Image as ImageIcon } from 'lucide-react'
+
+interface Props {
+  file: File | null
+  onChange: (file: File | null) => void
+}
+
+// Two inputs: one opens the gallery/file chooser, the other opens the camera on mobile.
+export default function PhotoPicker({ file, onChange }: Props) {
+  const chooseRef = useRef<HTMLInputElement>(null)
+  const cameraRef = useRef<HTMLInputElement>(null)
+  const pick = (e: React.ChangeEvent<HTMLInputElement>) => {
+    const f = e.target.files?.[0]
+    if (f) onChange(f)
+    e.target.value = ''
+  }
+  return (
+    <div>
+      <div style={{ display: 'flex', gap: 8, flexWrap: 'wrap' }}>
+        <button type="button" className="btn btn-sm" onClick={() => cameraRef.current?.click()}>
+          <Camera size={13} strokeWidth={1.75} /> Take photo
+        </button>
+        <button type="button" className="btn btn-sm" onClick={() => chooseRef.current?.click()}>
+          <ImageIcon size={13} strokeWidth={1.75} /> Choose image
+        </button>
+      </div>
+      <input ref={cameraRef} type="file" accept="image/*" capture="environment" onChange={pick} style={{ display: 'none' }} />
+      <input ref={chooseRef} type="file" accept="image/*" onChange={pick} style={{ display: 'none' }} />
+      {file && (
+        <div className="field-hint" style={{ marginTop: 6 }}>
+          {file.name}{' '}
+          <button type="button" className="btn btn-sm" onClick={() => onChange(null)}>Remove</button>
+        </div>
+      )}
+    </div>
+  )
+}
diff --git a/frontend/src/pages/AddReading.tsx b/frontend/src/pages/AddReading.tsx
new file mode 100644
index 0000000..733457c
--- /dev/null
+++ b/frontend/src/pages/AddReading.tsx
@@ -0,0 +1,122 @@
+import { useCallback, useEffect, useState } from 'react'
+import { Navigate } from 'react-router-dom'
+import { X } from 'lucide-react'
+import { useAuth } from '../components/AuthGate'
+import PhotoPicker from '../components/PhotoPicker'
+import { can, CATEGORY_DOT_CLASS } from '../types'
+import type { Meter } from '../types'
+import * as api from '../api'
+
+export default function AddReading() {
+  const { user } = useAuth()
+  const canEnter = can(user, 'readings')
+
+  const [meters, setMeters] = useState<Meter[]>([])
+  const [active, setActive] = useState<Meter | null>(null)
+  const [value, setValue] = useState('')
+  const [date, setDate] = useState(new Date().toISOString().slice(0, 10))
+  const [photo, setPhoto] = useState<File | null>(null)
+  const [error, setError] = useState<string | null>(null)
+  const [info, setInfo] = useState<string | null>(null)
+  const [saving, setSaving] = useState(false)
+
+  const load = useCallback(() => {
+    api.fetchMeters({ active: true }).then(setMeters).catch(err => setError(err.message))
+  }, [])
+  useEffect(() => { load() }, [load])
+
+  if (!canEnter) return <Navigate to="/meters" replace />
+
+  function open(m: Meter) {
+    setActive(m)
+    setValue('')
+    setPhoto(null)
+    setDate(new Date().toISOString().slice(0, 10))
+    setError(null)
+  }
+
+  async function submit() {
+    if (!active || value === '') { setError('Reading value is required'); return }
+    setSaving(true)
+    setError(null)
+    try {
+      const r = await api.createReading({ meter_id: active.id, reading_value: parseFloat(value), reading_date: date })
+      if (photo) await api.uploadReadingPhoto(r.id, photo)
+      setInfo(r.warning ? `${active.name}: ${r.warning}` : `Saved reading for ${active.name}`)
+      setActive(null)
+      load()
+    } catch (err) {
+      setError(err instanceof Error ? err.message : 'Save failed')
+    } finally {
+      setSaving(false)
+    }
+  }
+
+  return (
+    <div className="page">
+      <div className="page-header"><h1>Add reading</h1></div>
+
+      {error && !active && <div className="error-banner">{error}</div>}
+      {info && <div className="info-banner">{info}</div>}
+
+      {meters.length === 0 ? (
+        <div className="empty-state">No active meters.</div>
+      ) : (
+        <div style={{ display: 'grid', gridTemplateColumns: 'repeat(auto-fill, minmax(160px, 1fr))', gap: 12 }}>
+          {meters.map(m => (
+            <button
+              key={m.id}
+              className="card"
+              onClick={() => open(m)}
+              style={{ textAlign: 'left', cursor: 'pointer', marginBottom: 0 }}
+            >
+              <div style={{ fontWeight: 600, display: 'flex', alignItems: 'center', gap: 6 }}>
+                <span className={`cat-dot ${CATEGORY_DOT_CLASS[m.category_key] || ''}`} />{m.name}
+              </div>
+              <div className="field-hint">{m.category_name}{m.location ? ` · ${m.location}` : ''}</div>
+              <div className="field-hint" style={{ marginTop: 6 }}>
+                {m.latest_reading_value
+                  ? `${Number(m.latest_reading_value).toLocaleString()} ${m.reading_unit_label} · ${new Date(m.latest_reading_date!).toLocaleDateString('en-GB')}`
+                  : 'No readings yet'}
+              </div>
+            </button>
+          ))}
+        </div>
+      )}
+
+      {active && (
+        <div className="modal-overlay" onClick={() => setActive(null)}>
+          <div className="modal" onClick={e => e.stopPropagation()}>
+            <div className="modal-header">
+              <h2>{active.name}</h2>
+              <button className="modal-close" onClick={() => setActive(null)}><X size={18} strokeWidth={1.75} /></button>
+            </div>
+            {error && <div className="error-banner">{error}</div>}
+            <div className="field">
+              <label>Reading ({active.reading_unit_label})</label>
+              <input type="number" step="0.001" inputMode="decimal" autoFocus value={value}
+                onChange={e => setValue(e.target.value)} placeholder="e.g. 45231.5" />
+              {active.latest_reading_value && (
+                <div className="field-hint">
+                  Previous: {Number(active.latest_reading_value).toLocaleString()} {active.reading_unit_label} on {new Date(active.latest_reading_date!).toLocaleDateString('en-GB')}
+                </div>
+              )}
+            </div>
+            <div className="field">
+              <label>Date</label>
+              <input type="date" value={date} onChange={e => setDate(e.target.value)} />
+            </div>
+            <div className="field">
+              <label>Photo</label>
+              <PhotoPicker file={photo} onChange={setPhoto} />
+            </div>
+            <div className="modal-actions">
+              <button className="btn" onClick={() => setActive(null)}>Cancel</button>
+              <button className="btn btn-primary" onClick={submit} disabled={saving}>{saving ? 'Saving…' : 'Save reading'}</button>
+            </div>
+          </div>
+        </div>
+      )}
+    </div>
+  )
+}
diff --git a/frontend/src/pages/Readings.tsx b/frontend/src/pages/Readings.tsx
index 10c1a19..f703e65 100644
--- a/frontend/src/pages/Readings.tsx
+++ b/frontend/src/pages/Readings.tsx
@@ -3,6 +3,7 @@ import { Camera, Trash2 } from 'lucide-react'
 import { useAuth } from '../components/AuthGate'
 import { can } from '../types'
 import type { Meter, Reading } from '../types'
+import PhotoPicker from '../components/PhotoPicker'
 import * as api from '../api'
 
 export default function Readings() {
@@ -106,7 +107,7 @@ export default function Readings() {
             </div>
             <div className="field" style={{ marginBottom: 0 }}>
               <label>Photo</label>
-              <input type="file" accept="image/*" onChange={e => setPhoto(e.target.files?.[0] || null)} style={{ fontSize: 11 }} />
+              <PhotoPicker file={photo} onChange={setPhoto} />
             </div>
             <button className="btn btn-primary" onClick={submit} disabled={saving} style={{ marginBottom: 1 }}>
               {saving ? 'Saving…' : 'Add reading'}
@@ -142,7 +143,7 @@ export default function Readings() {
                       <a href={api.uploadUrl(r.photo_path)} target="_blank" rel="noreferrer">View</a>
                     ) : canEnter ? (
                       photoTargetId === r.id ? (
-                        <input type="file" accept="image/*" autoFocus onChange={e => e.target.files?.[0] && uploadPhoto(r.id, e.target.files[0])} />
+                        <PhotoPicker file={null} onChange={f => f && uploadPhoto(r.id, f)} />
                       ) : (
                         <button className="btn btn-sm" onClick={() => setPhotoTargetId(r.id)}><Camera size={13} strokeWidth={1.75} /></button>
                       )