diff --git a/front/src/applications/stdcm/components/StdcmForm/StdcmOpSchedule.tsx b/front/src/applications/stdcm/components/StdcmForm/StdcmOpSchedule.tsx
index 04be718fc60..0dc025d6a75 100644
--- a/front/src/applications/stdcm/components/StdcmForm/StdcmOpSchedule.tsx
+++ b/front/src/applications/stdcm/components/StdcmForm/StdcmOpSchedule.tsx
@@ -9,6 +9,7 @@ import { getSearchDatetimeWindow } from 'reducers/osrdconf/stdcmConf/selectors';
 import type { StdcmPathStep } from 'reducers/osrdconf/types';
 import { useAppDispatch } from 'store';
 import { formatDateString } from 'utils/date';
+import { Duration } from 'utils/duration';
 import { createStringSelectOptions } from 'utils/uiCoreHelpers';
 
 import type { ArrivalTimeTypes, ScheduleConstraint } from '../../types';
@@ -41,8 +42,8 @@ const StdcmOpSchedule = ({ disabled, pathStep, opId, isOrigin = false }: StdcmOp
 
   const tolerances = useMemo(
     () => ({
-      minusTolerance: pathStep.tolerances.before,
-      plusTolerance: pathStep.tolerances.after,
+      minusTolerance: pathStep.tolerances.before.total('second'),
+      plusTolerance: pathStep.tolerances.after.total('second'),
     }),
     [pathStep.tolerances]
   );
@@ -148,7 +149,12 @@ const StdcmOpSchedule = ({ disabled, pathStep, opId, isOrigin = false }: StdcmOp
                 dispatch(
                   updateStdcmPathStep({
                     id: pathStep.id,
-                    updates: { tolerances: { before: minusTolerance, after: plusTolerance } },
+                    updates: {
+                      tolerances: {
+                        before: new Duration({ seconds: minusTolerance }),
+                        after: new Duration({ seconds: plusTolerance }),
+                      },
+                    },
                   })
                 );
               }}
diff --git a/front/src/applications/stdcm/components/StdcmResults/SimulationReportSheet.tsx b/front/src/applications/stdcm/components/StdcmResults/SimulationReportSheet.tsx
index 0b28380ebe6..7670617c881 100644
--- a/front/src/applications/stdcm/components/StdcmResults/SimulationReportSheet.tsx
+++ b/front/src/applications/stdcm/components/StdcmResults/SimulationReportSheet.tsx
@@ -11,7 +11,6 @@ import { dateToHHMMSS, formatDateToString, formatDay } from 'utils/date';
 import { Duration } from 'utils/duration';
 import { msToKmh } from 'utils/physics';
 import { capitalizeFirstLetter } from 'utils/strings';
-import { secToMin } from 'utils/timeManipulation';
 
 import styles from './SimulationReportStyleSheet';
 import type { SimulationReportSheetProps } from '../../types';
@@ -203,12 +202,12 @@ const SimulationReportSheet = ({
                             <View style={styles.convoyAndRoute.tolerancesWidth}>
                               <Text style={styles.convoyAndRoute.tolerancesText}>
                                 {step.tolerances?.before
-                                  ? `+${secToMin(step.tolerances?.before)}`
+                                  ? `+${step.tolerances.before.total('minute')}`
                                   : ''}
                               </Text>
                               <Text style={styles.convoyAndRoute.tolerancesText}>
                                 {step.tolerances?.after
-                                  ? `-${secToMin(step.tolerances?.after)}`
+                                  ? `-${step.tolerances.after.total('minute')}`
                                   : ''}
                               </Text>
                             </View>
@@ -237,10 +236,10 @@ const SimulationReportSheet = ({
                             step.arrivalType === 'preciseTime' && (
                               <View style={styles.convoyAndRoute.tolerancesWidth}>
                                 <Text style={styles.convoyAndRoute.tolerancesText}>
-                                  {`+${secToMin(step.tolerances.before)}`}
+                                  {`+${step.tolerances.before.total('minute')}`}
                                 </Text>
                                 <Text style={styles.convoyAndRoute.tolerancesText}>
-                                  {`-${secToMin(step.tolerances.after)}`}
+                                  {`-${step.tolerances.after.total('minute')}`}
                                 </Text>
                               </View>
                             )}
diff --git a/front/src/applications/stdcm/utils/formatStdcmConf.ts b/front/src/applications/stdcm/utils/formatStdcmConf.ts
index 83a1fb6c843..c7dd9f45c8e 100644
--- a/front/src/applications/stdcm/utils/formatStdcmConf.ts
+++ b/front/src/applications/stdcm/utils/formatStdcmConf.ts
@@ -165,8 +165,8 @@ export const checkStdcmConf = (
       if (arrivalType === 'preciseTime' && arrival) {
         timingData = {
           arrival_time: arrival.toISOString(),
-          arrival_time_tolerance_before: sec2ms(tolerances?.before ?? 0),
-          arrival_time_tolerance_after: sec2ms(tolerances?.after ?? 0),
+          arrival_time_tolerance_before: tolerances.before.ms,
+          arrival_time_tolerance_after: tolerances.after.ms,
         };
       }
     }
diff --git a/front/src/reducers/osrdconf/stdcmConf/index.ts b/front/src/reducers/osrdconf/stdcmConf/index.ts
index 152d321bcdb..4d9b3530c71 100644
--- a/front/src/reducers/osrdconf/stdcmConf/index.ts
+++ b/front/src/reducers/osrdconf/stdcmConf/index.ts
@@ -14,9 +14,10 @@ import { defaultCommonConf, buildCommonConfReducers } from 'reducers/osrdconf/os
 import type { OsrdStdcmConfState, StdcmPathStep } from 'reducers/osrdconf/types';
 import { addElementAtIndex, replaceElementAtIndex } from 'utils/array';
 import { isArrivalDateInSearchTimeWindow } from 'utils/date';
+import { Duration } from 'utils/duration';
 import type { ArrayElement, PickAndNonNullableFields } from 'utils/types';
 
-const DEFAULT_TOLERANCE = 1800; // 30min
+const DEFAULT_TOLERANCE = new Duration({ minutes: 30 });
 
 export const stdcmConfInitialState: OsrdStdcmConfState = {
   ...defaultCommonConf,
diff --git a/front/src/reducers/osrdconf/stdcmConf/stdcmConfReducers.spec.ts b/front/src/reducers/osrdconf/stdcmConf/stdcmConfReducers.spec.ts
index 1529f089f14..45793c03577 100644
--- a/front/src/reducers/osrdconf/stdcmConf/stdcmConfReducers.spec.ts
+++ b/front/src/reducers/osrdconf/stdcmConf/stdcmConfReducers.spec.ts
@@ -25,6 +25,7 @@ import {
 } from 'reducers/osrdconf/stdcmConf';
 import type { OsrdStdcmConfState, StandardAllowance, StdcmPathStep } from 'reducers/osrdconf/types';
 import { createStoreWithoutMiddleware } from 'store';
+import { Duration } from 'utils/duration';
 
 import commonConfBuilder from '../osrdConfCommon/__tests__/commonConfBuilder';
 import testCommonConfReducers from '../osrdConfCommon/__tests__/utils';
@@ -180,8 +181,8 @@ describe('stdcmConfReducers', () => {
         arrivalType: ArrivalTimeTypes.ASAP,
         arrival: new Date('2024-08-12T15:45:00.000+02:00'),
         tolerances: {
-          before: 60,
-          after: 60,
+          before: new Duration({ seconds: 60 }),
+          after: new Duration({ seconds: 60 }),
         },
       };
 
@@ -210,8 +211,8 @@ describe('stdcmConfReducers', () => {
         arrivalType: ArrivalTimeTypes.ASAP,
         arrival: new Date('2024-08-12T15:45:00.000+02:00'),
         tolerances: {
-          before: 60,
-          after: 60,
+          before: new Duration({ seconds: 60 }),
+          after: new Duration({ seconds: 60 }),
         },
       };
 
diff --git a/front/src/reducers/osrdconf/types.ts b/front/src/reducers/osrdconf/types.ts
index be4d7010b18..4e33ac3d60c 100644
--- a/front/src/reducers/osrdconf/types.ts
+++ b/front/src/reducers/osrdconf/types.ts
@@ -123,7 +123,7 @@ export type StdcmPathStep = {
       arrivalType: ArrivalTimeTypes;
       // TODO: make arrival non nullable (/!\ store migration)
       arrival?: Date;
-      tolerances: { before: number; after: number };
+      tolerances: { before: Duration; after: Duration };
     }
 );