diff --git a/src/components/Routines/screens/Detail/WorkoutLogs.test.tsx b/src/components/Routines/screens/Detail/WorkoutLogs.test.tsx
index ac1458c4a..3b35b3f86 100644
--- a/src/components/Routines/screens/Detail/WorkoutLogs.test.tsx
+++ b/src/components/Routines/screens/Detail/WorkoutLogs.test.tsx
@@ -21,6 +21,9 @@ import {
 import type { Mock } from 'vitest';
 
 vi.mock("@/components/Routines/queries");
+vi.mock('@/components/User/queries/profile', () => ({
+    useProfileQuery: () => ({ isLoading: false, data: { useMetric: true } }),
+}));
 
 const queryClient = new QueryClient();
 
diff --git a/src/components/Routines/widgets/LogWidgets.test.tsx b/src/components/Routines/widgets/LogWidgets.test.tsx
index f1f928952..305db406f 100644
--- a/src/components/Routines/widgets/LogWidgets.test.tsx
+++ b/src/components/Routines/widgets/LogWidgets.test.tsx
@@ -1,7 +1,9 @@
 import { render, screen } from '@testing-library/react';
 import userEvent from "@testing-library/user-event";
 import { useDeleteRoutineLogQuery, useEditRoutineLogQuery } from '@/components/Routines/queries';
-import { ExerciseLog } from "@/components/Routines/widgets/LogWidgets";
+import { WorkoutLog } from "@/components/Routines/models/WorkoutLog";
+import { ExerciseLog, formatData } from "@/components/Routines/widgets/LogWidgets";
+import { WEIGHT_UNIT_KG, WEIGHT_UNIT_LB } from "@/core/lib/consts";
 import { testExerciseBenchPress } from "@/tests/exerciseTestdata";
 import { testWorkoutLogs } from "@/tests/workoutLogsRoutinesTestData";
 import type { Mock } from 'vitest';
@@ -10,6 +12,9 @@ vi.mock('@/components/Routines/queries', () => ({
     useDeleteRoutineLogQuery: vi.fn(),
     useEditRoutineLogQuery: vi.fn()
 }));
+vi.mock('@/components/User/queries/profile', () => ({
+    useProfileQuery: () => ({ isLoading: false, data: { useMetric: true } }),
+}));
 
 describe('ExerciseLog', () => {
     let mockDeleteMutate: Mock;
@@ -75,4 +80,22 @@ describe('ExerciseLog', () => {
         expect(mockDeleteMutate).not.toHaveBeenCalled();
         expect(mockEditMutate).toHaveBeenCalled();
     });
-});
\ No newline at end of file
+});
+
+describe('formatData', () => {
+    const logIn = (weight: number | null, weightUnitId: number | null) =>
+        new WorkoutLog({ ...testWorkoutLogs[0], weight: weight, weightUnitId: weightUnitId });
+
+    test('converts weights logged in kg or lb to the chart unit', () => {
+        const data = [logIn(100, WEIGHT_UNIT_LB), logIn(50, WEIGHT_UNIT_KG)];
+
+        expect(formatData(data, 'kg').map(entry => entry.value)).toEqual([45.36, 50]);
+        expect(formatData(data, 'lb').map(entry => entry.value)).toEqual([100, 110.23]);
+    });
+
+    test('passes other units and missing weights through unchanged', () => {
+        const data = [logIn(12, 3), logIn(null, WEIGHT_UNIT_LB)];
+
+        expect(formatData(data, 'lb').map(entry => entry.value)).toEqual([12, null]);
+    });
+});
diff --git a/src/components/Routines/widgets/LogWidgets.tsx b/src/components/Routines/widgets/LogWidgets.tsx
index 7c33104d7..6ee703a75 100644
--- a/src/components/Routines/widgets/LogWidgets.tsx
+++ b/src/components/Routines/widgets/LogWidgets.tsx
@@ -18,6 +18,7 @@ import {
 } from "@mui/x-data-grid";
 import { FormQueryErrors } from "@/core/ui/Widgets/FormError";
 import { Exercise } from "@/components/Exercises";
+import { useDisplayWeightUnit } from "@/components/Measurements";
 import { RIR_VALUES_SELECT_LIST } from "@/components/Routines/models/BaseConfig";
 import { WorkoutLog } from "@/components/Routines/models/WorkoutLog";
 import { useDeleteRoutineLogQuery, useEditRoutineLogQuery } from "@/components/Routines/queries";
@@ -36,8 +37,9 @@ import {
 } from "recharts";
 import { NameType, ValueType } from "recharts/types/component/DefaultTooltipContent";
 import { generateChartColors } from "@/core/lib/colors";
-import { PAGINATION_OPTIONS } from "@/core/lib/consts";
+import { PAGINATION_OPTIONS, WEIGHT_UNIT_KG, WEIGHT_UNIT_LB } from "@/core/lib/consts";
 import { dateToLocale, luxonDateTimeToLocale } from "@/core/lib/date";
+import { convertWeight, WeightUnit } from "@/core/lib/weightUnit";
 
 
 export const ExerciseLog = (props: { exercise: Exercise, routineId: number, logEntries: WorkoutLog[] | undefined }) => {
@@ -243,13 +245,18 @@ export const ExerciseLog = (props: { exercise: Exercise, routineId: number, logE
  * Format the log entries so that they can be passed to the chart
  *
  * This is mostly due to the time, which needs to be a number to be shown
- * in the scatter plot
+ * in the scatter plot. Weights logged in kg or lb are converted to the unit
+ * the chart is drawn in, other units are passed through unchanged.
  */
-const formatData = (data: WorkoutLog[]) =>
+export const formatData = (data: WorkoutLog[], unit: WeightUnit) =>
     data.map((log) => {
+        const logUnit: WeightUnit | null = log.weightUnitId === WEIGHT_UNIT_KG
+            ? 'kg'
+            : log.weightUnitId === WEIGHT_UNIT_LB ? 'lb' : null;
+
         return {
             id: log.id,
-            value: log.weight,
+            value: log.weight !== null && logUnit !== null ? convertWeight(log.weight, logUnit, unit) : log.weight,
             time: log.date.getTime(),
             entry: log,
         };
@@ -279,6 +286,9 @@ const ExerciseLogTooltip = ({ active, payload }: TooltipContentProps<ValueType,
 };
 
 export const TimeSeriesChart = (props: { data: WorkoutLog[] }) => {
+    const { t } = useTranslation();
+    const weightUnit = useDisplayWeightUnit();
+    const weightUnitLabel = t(weightUnit === 'lb' ? 'server.lb' : 'server.kg');
 
     // Group by rep count
     //
@@ -306,12 +316,12 @@ export const TimeSeriesChart = (props: { data: WorkoutLog[] }) => {
                     domain={["auto", "auto"]}
                     dataKey="value"
                     name="Value"
-                    unit="kg"
+                    unit={weightUnitLabel}
                 />
 
                 {Array.from(result).map(([key, value]) => {
                         const color = colorGenerator.next().value!;
-                        const formattedData = formatData(value);
+                        const formattedData = formatData(value, weightUnit);
 
                         return <Scatter
                             key={key}