diff --git a/src/components/dashboard/ClientsGraph.tsx b/src/components/dashboard/ClientsGraph.tsx
index 17837ae..3ad42f2 100644
--- a/src/components/dashboard/ClientsGraph.tsx
+++ b/src/components/dashboard/ClientsGraph.tsx
@@ -12,7 +12,7 @@ import React, { Component, RefObject } from "react";
 import ReactDOM from "react-dom";
 import { Line } from "react-chartjs-2";
 import { WithNamespaces, withNamespaces } from "react-i18next";
-import { getIntervalForRange, padNumber } from "../../util";
+import { getIntervalForRange, padNumber } from "../../util/graphUtils";
 import api from "../../util/api";
 import ChartTooltip from "./ChartTooltip";
 import { WithAPIData } from "../common/WithAPIData";
diff --git a/src/components/dashboard/QueriesGraph.tsx b/src/components/dashboard/QueriesGraph.tsx
index e321bb2..759bfb9 100644
--- a/src/components/dashboard/QueriesGraph.tsx
+++ b/src/components/dashboard/QueriesGraph.tsx
@@ -10,7 +10,7 @@
 
 import React, { Component } from "react";
 import { WithNamespaces, withNamespaces } from "react-i18next";
-import { getIntervalForRange, padNumber } from "../../util";
+import { getIntervalForRange, padNumber } from "../../util/graphUtils";
 import api from "../../util/api";
 import { WithAPIData } from "../common/WithAPIData";
 import { ChartData, ChartOptions, TimeUnit } from "chart.js";
diff --git a/src/components/log/QueryLog.tsx b/src/components/log/QueryLog.tsx
index b746ca1..16aa3fb 100644
--- a/src/components/log/QueryLog.tsx
+++ b/src/components/log/QueryLog.tsx
@@ -20,7 +20,7 @@ import i18next from "i18next";
 import { WithNamespaces, withNamespaces } from "react-i18next";
 import debounce from "lodash.debounce";
 import moment from "moment";
-import { padNumber } from "../../util";
+import { padNumber } from "../../util/graphUtils";
 import api from "../../util/api";
 import { dateRanges } from "../../util/dateRanges";
 import { TranslatedTimeRangeSelector } from "../dashboard/TimeRangeSelector";
diff --git a/src/util/__tests__/graphUtils.test.tsx b/src/util/__tests__/graphUtils.test.tsx
new file mode 100644
index 0000000..3258910
--- /dev/null
+++ b/src/util/__tests__/graphUtils.test.tsx
@@ -0,0 +1,51 @@
+/* Pi-hole: A black hole for Internet advertisements
+ * (c) 2019 Pi-hole, LLC (https://pi-hole.net)
+ * Network-wide ad blocking via your own hardware.
+ *
+ * Web Interface
+ * Graph utility tests
+ *
+ * This file is copyright under the latest version of the EUPL.
+ * Please see LICENSE file for your rights under this license. */
+
+import { padNumber, getIntervalForRange } from "../graphUtils";
+import { TimeRange } from "../../components/common/context/TimeRangeContext";
+import moment from "moment";
+
+describe("padNumber", () => {
+  it("pads 0 to 00", () => {
+    expect(padNumber(0)).toEqual("00");
+  });
+
+  it("pads 1 to 01", () => {
+    expect(padNumber(1)).toEqual("01");
+  });
+
+  it("pads 12 to 12", () => {
+    expect(padNumber(12)).toEqual("12");
+  });
+});
+
+describe("getIntervalForRange", () => {
+  it("returns 10 minutes for 24 hours", () => {
+    const range: TimeRange = {
+      name: "24 Hours",
+      from: moment().subtract(1, "day"),
+      until: moment()
+    };
+
+    expect(getIntervalForRange(range)).toEqual(10 * 60);
+  });
+
+  it("returns 1 day for 144 days", () => {
+    const range: TimeRange = {
+      name: "144 days",
+      // Use seconds instead of days to ensure the difference in epoch time is
+      // equal to 144 days
+      from: moment().subtract(144 * 24 * 60 * 60, "seconds"),
+      until: moment()
+    };
+
+    expect(getIntervalForRange(range)).toEqual(24 * 60 * 60);
+  });
+});
diff --git a/src/util/index.tsx b/src/util/graphUtils.tsx
similarity index 97%
rename from src/util/index.tsx
rename to src/util/graphUtils.tsx
index d339154..b49c4e8 100644
--- a/src/util/index.tsx
+++ b/src/util/graphUtils.tsx
@@ -3,7 +3,7 @@
  * Network-wide ad blocking via your own hardware.
  *
  * Web Interface
- * Various utilities
+ * Graph utility functions
  *
  * This file is copyright under the latest version of the EUPL.
  * Please see LICENSE file for your rights under this license. */