diff --git a/tests/test_claims_frontend_rtc_scaling.py b/tests/test_claims_frontend_rtc_scaling.py
new file mode 100644
index 000000000..5f85def9f
--- /dev/null
+++ b/tests/test_claims_frontend_rtc_scaling.py
@@ -0,0 +1,62 @@
+"""
+Regression test for the claims-page RTC display scaling bug.
+
+`reward_urtc` is denominated in micro-RTC (10^6 units per RTC). The backend
+(node/claims_submission.py) converts to human-readable RTC by dividing by
+1_000_000 in every place it reports an amount. The frontend `formatRtc()`
+helper in web/claims/claims.js must use the *same* divisor, otherwise every
+reward shown on the claim page (dropdown, summary, history, stats, success
+message, CSV export) is off by 100x.
+
+Concrete input -> output:
+    reward_urtc = 1_500_000  (== 1.5 RTC)
+    correct   : 1_500_000 / 1_000_000       -> "1.500000"
+    buggy     : 1_500_000 / 100_000_000     -> "0.015000"   (100x too small)
+"""
+
+import re
+from pathlib import Path
+
+REPO_ROOT = Path(__file__).resolve().parents[1]
+CLAIMS_JS = REPO_ROOT / "web" / "claims" / "claims.js"
+CLAIMS_BACKEND = REPO_ROOT / "node" / "claims_submission.py"
+
+MICRO_RTC_PER_RTC = 1_000_000
+
+
+def _extract_format_rtc_divisor() -> int:
+    """Return the integer divisor used inside formatRtc() in claims.js."""
+    source = CLAIMS_JS.read_text(encoding="utf-8")
+    m = re.search(
+        r"function\s+formatRtc\s*\([^)]*\)\s*\{.*?/\s*([0-9_]+)\s*\)",
+        source,
+        re.DOTALL,
+    )
+    assert m, "Could not locate the divisor inside formatRtc() in claims.js"
+    return int(m.group(1).replace("_", ""))
+
+
+def test_format_rtc_uses_micro_rtc_divisor():
+    assert _extract_format_rtc_divisor() == MICRO_RTC_PER_RTC, (
+        "formatRtc() must divide micro-RTC by 1_000_000 to render RTC. "
+        "Any other divisor (e.g. 100_000_000) misreports rewards on the claim page."
+    )
+
+
+def test_frontend_divisor_matches_backend_conversion():
+    """The frontend divisor must match the backend reward_urtc -> RTC divisor."""
+    backend = CLAIMS_BACKEND.read_text(encoding="utf-8")
+    backend_divisors = {
+        int(d.replace("_", ""))
+        for d in re.findall(r"reward_urtc\"?\]?\s*/\s*([0-9_]+)", backend)
+    }
+    # Backend consistently uses 1_000_000 for reward_urtc conversion.
+    assert MICRO_RTC_PER_RTC in backend_divisors, backend_divisors
+    assert _extract_format_rtc_divisor() in backend_divisors, (
+        "Frontend formatRtc() divisor does not match the backend micro-RTC divisor."
+    )
+
+
+def test_worked_example_1_5_rtc():
+    divisor = _extract_format_rtc_divisor()
+    assert f"{1_500_000 / divisor:.6f}" == "1.500000"
diff --git a/web/claims/claims.js b/web/claims/claims.js
index a785cabec..db416e081 100644
--- a/web/claims/claims.js
+++ b/web/claims/claims.js
@@ -112,7 +112,10 @@ function formatCheckName(value) {
  * @returns {string}
  */
 function formatRtc(urtc) {
-  return (safeNumber(urtc) / 100_000_000).toFixed(6);
+  // reward_urtc is denominated in micro-RTC (10^6 units per RTC), matching the
+  // backend convention in node/claims_submission.py (reward_urtc / 1_000_000).
+  // Dividing by 10^8 here understated every displayed amount by 100x.
+  return (safeNumber(urtc) / 1_000_000).toFixed(6);
 }
 
 /**