diff --git a/src/expert-insurer/expert-insurer.file-summary.spec.ts b/src/expert-insurer/expert-insurer.file-summary.spec.ts
new file mode 100644
index 0000000..1ac54c7
--- /dev/null
+++ b/src/expert-insurer/expert-insurer.file-summary.spec.ts
@@ -0,0 +1,52 @@
+import { ExpertInsurerService } from "./expert-insurer.service";
+
+describe("insurer expert file summaries", () => {
+  const service = Object.create(
+    ExpertInsurerService.prototype,
+  ) as ExpertInsurerService;
+
+  it("calculates blame review duration in minutes on the backend", () => {
+    const summary = (service as any).mapBlameFileSummaryForInsurerExpert({
+      _id: "6aa50ce70545fc1906433c85",
+      publicId: "RPT832-00049",
+      requestNo: "BL-RPT832-000049",
+      type: "THIRD_PARTY",
+      status: "WAITING_FOR_SIGNATURES",
+      blameStatus: "AGREED",
+      createdAt: new Date("2026-06-21T12:42:28.000Z"),
+      updatedAt: new Date("2026-06-21T15:32:28.000Z"),
+    });
+
+    expect(summary.reviewDurationMinutes).toBe(170);
+  });
+
+  it("calculates claim review duration with the same contract", () => {
+    const summary = (service as any).mapClaimFileSummaryForInsurerExpert({
+      _id: "6aa50ce70545fc1906433c86",
+      publicId: "RPT832-00049",
+      createdAt: "2026-06-21T12:42:28.000Z",
+      updatedAt: "2026-06-21T12:43:58.000Z",
+    });
+
+    expect(summary.reviewDurationMinutes).toBe(1.5);
+  });
+
+  it("returns null instead of NaN when a duration timestamp is unavailable", () => {
+    const summary = (service as any).mapBlameFileSummaryForInsurerExpert({
+      _id: "6aa50ce70545fc1906433c85",
+      createdAt: "invalid",
+    });
+
+    expect(summary.reviewDurationMinutes).toBeNull();
+  });
+
+  it("clamps malformed negative durations to zero", () => {
+    const summary = (service as any).mapClaimFileSummaryForInsurerExpert({
+      _id: "6aa50ce70545fc1906433c86",
+      createdAt: "2026-06-21T15:32:28.000Z",
+      updatedAt: "2026-06-21T12:42:28.000Z",
+    });
+
+    expect(summary.reviewDurationMinutes).toBe(0);
+  });
+});
diff --git a/src/expert-insurer/expert-insurer.service.ts b/src/expert-insurer/expert-insurer.service.ts
index ba50fa4..227a42d 100644
--- a/src/expert-insurer/expert-insurer.service.ts
+++ b/src/expert-insurer/expert-insurer.service.ts
@@ -264,6 +264,18 @@ export class ExpertInsurerService {
     return String(aid);
   }
 
+  private calculateReviewDurationMinutes(
+    createdAt: Date | string | undefined,
+    updatedAt: Date | string | undefined,
+  ): number | null {
+    const startedAtMs = new Date(createdAt as any).getTime();
+    const reviewedAtMs = new Date(updatedAt as any).getTime();
+    if (Number.isNaN(startedAtMs) || Number.isNaN(reviewedAtMs)) return null;
+
+    const durationMinutes = Math.max(reviewedAtMs - startedAtMs, 0) / 60_000;
+    return Math.round(durationMinutes * 100) / 100;
+  }
+
   private mapBlameFileSummaryForInsurerExpert(b: any) {
     return {
       kind: "blame" as const,
@@ -275,6 +287,10 @@ export class ExpertInsurerService {
       blameStatus: b.blameStatus,
       createdAt: b.createdAt,
       updatedAt: b.updatedAt,
+      reviewDurationMinutes: this.calculateReviewDurationMinutes(
+        b.createdAt,
+        b.updatedAt,
+      ),
     };
   }
 
@@ -288,6 +304,10 @@ export class ExpertInsurerService {
       claimStatus: c.claimStatus,
       createdAt: c.createdAt,
       updatedAt: c.updatedAt,
+      reviewDurationMinutes: this.calculateReviewDurationMinutes(
+        c.createdAt,
+        c.updatedAt,
+      ),
     };
   }