diff --git a/frontend/src/components/Dashboard/BarWidget.tsx b/frontend/src/components/Dashboard/BarWidget.tsx
index be8c23f..ea126bf 100644
--- a/frontend/src/components/Dashboard/BarWidget.tsx
+++ b/frontend/src/components/Dashboard/BarWidget.tsx
@@ -1,6 +1,97 @@
+import { useLiveValue } from "@/components/Flow/liveStore"
+import { cn } from "@/lib/utils"
 import type { WidgetProps } from "./widgets"
 
-/** A bar — a stub until the bar widget is written. */
-export function BarWidget(_props: WidgetProps) {
-  return <p className="text-sm text-muted-foreground">—</p>
+// Local copies: `widgets.tsx` imports this module, so its helpers cannot be
+// imported back without closing the cycle (`ChartWidget.tsx` does the same).
+const config = (widget: WidgetProps["widget"]) =>
+  (widget.config ?? {}) as Record<string, unknown>
+
+const text = (value: unknown) => (value == null ? "" : String(value))
+
+const num = (value: unknown, fallback: number) => {
+  const parsed = Number(value)
+  return Number.isFinite(parsed) ? parsed : fallback
+}
+
+/** Below this the reading no longer fits on the fill and moves off its end. */
+const FITS = 0.3
+
+/**
+ * A level, drawn as a horizontal bar with its reading written on it.
+ *
+ * A second message can be nested inside the first — the PV share of an
+ * inverter's input — and is drawn on top of the fill on the same scale, so
+ * containment is what the picture shows rather than something to work out.
+ */
+export function BarWidget({ widget }: WidgetProps) {
+  const cfg = config(widget)
+  const message = text(cfg.message)
+  const nested = text(cfg.inner)
+  const outer = useLiveValue(message || undefined)
+  const inner = useLiveValue(nested || undefined)
+  if (!message)
+    return <p className="text-sm text-muted-foreground">Pick a message.</p>
+
+  const min = num(cfg.min, 0)
+  const max = num(cfg.max, 100)
+  const span = max - min || 1
+  const precision = cfg.precision === undefined ? 1 : num(cfg.precision, 1)
+  const unit = cfg.unit ? text(cfg.unit) : ""
+
+  const reading = (live: unknown) => (typeof live === "number" ? live : null)
+  const fractionOf = (value: number | null) =>
+    value === null ? 0 : Math.min(1, Math.max(0, (value - min) / span))
+  const write = (value: number | null) =>
+    value === null ? "—" : `${value.toFixed(precision)}${unit}`
+
+  const value = reading(outer?.value)
+  const innerValue = nested ? reading(inner?.value) : null
+  const fraction = fractionOf(value)
+  const fits = fraction >= FITS
+
+  return (
+    <div
+      className="grid gap-1.5"
+      role="img"
+      aria-label={
+        nested
+          ? `${write(value)} of ${max}${unit}, ${write(innerValue)} of it from ${nested}`
+          : `${write(value)} of ${max}${unit}`
+      }
+    >
+      <div className="relative h-8 w-full overflow-hidden rounded-full bg-muted">
+        <div
+          data-testid="bar-fill"
+          className="absolute inset-y-0 left-0 rounded-full bg-primary"
+          style={{ width: `${fraction * 100}%` }}
+        />
+        {innerValue === null ? null : (
+          <div
+            data-testid="bar-inner"
+            className="absolute inset-y-1 left-0 rounded-full bg-chart-5"
+            style={{ width: `${fractionOf(innerValue) * 100}%` }}
+          />
+        )}
+        <span
+          className={cn(
+            "absolute inset-y-0 flex items-center px-2 text-sm tabular-nums",
+            fits ? "text-primary-foreground" : "text-foreground",
+          )}
+          style={
+            fits
+              ? { right: `${(1 - fraction) * 100}%` }
+              : { left: `${fraction * 100}%` }
+          }
+        >
+          {write(value)}
+        </span>
+      </div>
+      {innerValue === null ? null : (
+        <p className="truncate text-xs text-muted-foreground">
+          {nested} {write(innerValue)}
+        </p>
+      )}
+    </div>
+  )
 }