diff --git a/src/app/api/timesheets/utils.ts b/src/app/api/timesheets/utils.ts
index 22d31ce..7a6dad3 100644
--- a/src/app/api/timesheets/utils.ts
+++ b/src/app/api/timesheets/utils.ts
@@ -1,4 +1,13 @@
-import { LeaveEntry, TimeEntry } from "./actions";
+import { getPublicHolidaysForNYears } from "@/app/utils/holidayUtils";
+import { HolidaysResult } from "../holidays";
+import {
+  LeaveEntry,
+  RecordLeaveInput,
+  RecordTimesheetInput,
+  TimeEntry,
+} from "./actions";
+import { convertDateArrayToString } from "@/app/utils/formatUtil";
+import compact from "lodash/compact";
 
 export type TimeEntryError = {
   [field in keyof TimeEntry]?: string;
@@ -6,7 +15,7 @@ export type TimeEntryError = {
 
 /**
  * @param entry - the time entry
- * @returns the field where there is an error, or an empty string if there is none
+ * @returns an object where the keys are the error fields and the values the error message, and undefined if there are no errors
  */
 export const validateTimeEntry = (
   entry: Partial<TimeEntry>,
@@ -58,6 +67,61 @@ export const isValidLeaveEntry = (entry: Partial<LeaveEntry>): string => {
   return error;
 };
 
+export const validateTimesheet = (
+  timesheet: RecordTimesheetInput,
+  leaveRecords: RecordLeaveInput,
+  companyHolidays: HolidaysResult[],
+): { [date: string]: string } | undefined => {
+  const errors: { [date: string]: string } = {};
+
+  const holidays = new Set(
+    compact([
+      ...getPublicHolidaysForNYears(2).map((h) => h.date),
+      ...companyHolidays.map((h) => convertDateArrayToString(h.date)),
+    ]),
+  );
+
+  Object.keys(timesheet).forEach((date) => {
+    const timeEntries = timesheet[date];
+
+    // Check each entry
+    for (const entry of timeEntries) {
+      const entryErrors = validateTimeEntry(entry, holidays.has(date));
+
+      if (entryErrors) {
+        errors[date] = "There are errors in the entries";
+        return;
+      }
+    }
+
+    // Check total hours
+    const leaves = leaveRecords[date];
+    const leaveHours =
+      leaves?.reduce((acc, entry) => acc + entry.inputHours, 0) || 0;
+
+    const totalNormalHours = timeEntries.reduce((acc, entry) => {
+      return acc + (entry.inputHours || 0);
+    }, 0);
+
+    const totalOtHours = timeEntries.reduce((acc, entry) => {
+      return acc + (entry.otHours || 0);
+    }, 0);
+
+    if (totalNormalHours > DAILY_NORMAL_MAX_HOURS) {
+      errors[date] =
+        "The daily normal hours cannot be more than {{DAILY_NORMAL_MAX_HOURS}}. Please use other hours for exceeding hours.";
+    } else if (
+      totalNormalHours + totalOtHours + leaveHours >
+      TIMESHEET_DAILY_MAX_HOURS
+    ) {
+      errors[date] =
+        "The daily total hours cannot be more than {{TIMESHEET_DAILY_MAX_HOURS}}";
+    }
+  });
+
+  return Object.keys(errors).length > 0 ? errors : undefined;
+};
+
 export const DAILY_NORMAL_MAX_HOURS = 8;
 export const LEAVE_DAILY_MAX_HOURS = 8;
 export const TIMESHEET_DAILY_MAX_HOURS = 20;
diff --git a/src/components/DateHoursTable/DateHoursList.tsx b/src/components/DateHoursTable/DateHoursList.tsx
index 685aef9..d54e930 100644
--- a/src/components/DateHoursTable/DateHoursList.tsx
+++ b/src/components/DateHoursTable/DateHoursList.tsx
@@ -17,6 +17,7 @@ import dayjs from "dayjs";
 import React, { useCallback, useState } from "react";
 import { useTranslation } from "react-i18next";
 import {
+  DAILY_NORMAL_MAX_HOURS,
   LEAVE_DAILY_MAX_HOURS,
   TIMESHEET_DAILY_MAX_HOURS,
 } from "@/app/api/timesheets/utils";
@@ -32,6 +33,7 @@ interface Props<EntryComponentProps = object> {
     EntryComponentProps & { date: string }
   >;
   entryComponentProps: EntryComponentProps;
+  errorComponent?: React.ReactNode;
 }
 
 function DateHoursList<EntryTableProps>({
@@ -41,6 +43,7 @@ function DateHoursList<EntryTableProps>({
   EntryComponent,
   entryComponentProps,
   companyHolidays,
+  errorComponent,
 }: Props<EntryTableProps>) {
   const {
     t,
@@ -83,15 +86,22 @@ function DateHoursList<EntryTableProps>({
               leaves?.reduce((acc, entry) => acc + entry.inputHours, 0) || 0;
 
             const timesheet = timesheetEntries[day];
-            const timesheetHours =
+            const timesheetNormalHours =
               timesheet?.reduce(
-                (acc, entry) =>
-                  acc + (entry.inputHours || 0) + (entry.otHours || 0),
+                (acc, entry) => acc + (entry.inputHours || 0),
                 0,
               ) || 0;
+            const timesheetOtHours =
+              timesheet?.reduce(
+                (acc, entry) => acc + (entry.otHours || 0),
+                0,
+              ) || 0;
+            const timesheetHours = timesheetNormalHours + timesheetOtHours;
 
             const dailyTotal = leaveHours + timesheetHours;
 
+            const normalHoursExceeded =
+              timesheetNormalHours > DAILY_NORMAL_MAX_HOURS;
             const leaveExceeded = leaveHours > LEAVE_DAILY_MAX_HOURS;
             const dailyTotalExceeded = dailyTotal > TIMESHEET_DAILY_MAX_HOURS;
 
@@ -122,7 +132,9 @@ function DateHoursList<EntryTableProps>({
                         sx={{
                           display: "flex",
                           justifyContent: "space-between",
+                          flexWrap: "wrap",
                           alignItems: "baseline",
+                          color: normalHoursExceeded ? "error.main" : undefined,
                         }}
                       >
                         <Typography variant="body2">
@@ -131,6 +143,21 @@ function DateHoursList<EntryTableProps>({
                         <Typography>
                           {manhourFormatter.format(timesheetHours)}
                         </Typography>
+                        {normalHoursExceeded && (
+                          <Typography
+                            component="div"
+                            width="100%"
+                            variant="caption"
+                            paddingInlineEnd="40%"
+                          >
+                            {t(
+                              "The daily normal hours cannot be more than {{DAILY_NORMAL_MAX_HOURS}}. Please use other hours for exceeding hours.",
+                              {
+                                DAILY_NORMAL_MAX_HOURS,
+                              },
+                            )}
+                          </Typography>
+                        )}
                       </Box>
                       <Box
                         sx={{
@@ -182,9 +209,9 @@ function DateHoursList<EntryTableProps>({
                             variant="caption"
                           >
                             {t(
-                              "The daily total hours cannot be more than {{hours}}",
+                              "The daily total hours cannot be more than {{TIMESHEET_DAILY_MAX_HOURS}}",
                               {
-                                hours: TIMESHEET_DAILY_MAX_HOURS,
+                                TIMESHEET_DAILY_MAX_HOURS,
                               },
                             )}
                           </Typography>
@@ -198,6 +225,7 @@ function DateHoursList<EntryTableProps>({
           })}
         </Box>
       )}
+      {errorComponent}
       <Box padding={2} display="flex" justifyContent="flex-end">
         {isDateSelected ? (
           <Button
diff --git a/src/components/DateHoursTable/DateHoursTable.tsx b/src/components/DateHoursTable/DateHoursTable.tsx
index 8328bd9..907b105 100644
--- a/src/components/DateHoursTable/DateHoursTable.tsx
+++ b/src/components/DateHoursTable/DateHoursTable.tsx
@@ -21,6 +21,7 @@ import dayjs from "dayjs";
 import React, { useState } from "react";
 import { useTranslation } from "react-i18next";
 import {
+  DAILY_NORMAL_MAX_HOURS,
   LEAVE_DAILY_MAX_HOURS,
   TIMESHEET_DAILY_MAX_HOURS,
 } from "@/app/api/timesheets/utils";
@@ -112,14 +113,15 @@ function DayRow<EntryTableProps>({
     leaves?.reduce((acc, entry) => acc + entry.inputHours, 0) || 0;
 
   const timesheet = timesheetEntries[day];
-  const timesheetHours =
-    timesheet?.reduce(
-      (acc, entry) => acc + (entry.inputHours || 0) + (entry.otHours || 0),
-      0,
-    ) || 0;
+  const timesheetNormalHours =
+    timesheet?.reduce((acc, entry) => acc + (entry.inputHours || 0), 0) || 0;
+  const timesheetOtHours =
+    timesheet?.reduce((acc, entry) => acc + (entry.otHours || 0), 0) || 0;
+  const timesheetHours = timesheetNormalHours + timesheetOtHours;
 
   const dailyTotal = leaveHours + timesheetHours;
 
+  const normalHoursExceeded = timesheetNormalHours > DAILY_NORMAL_MAX_HOURS;
   const leaveExceeded = leaveHours > LEAVE_DAILY_MAX_HOURS;
   const dailyTotalExceeded = dailyTotal > TIMESHEET_DAILY_MAX_HOURS;
 
@@ -146,7 +148,27 @@ function DayRow<EntryTableProps>({
           )}
         </TableCell>
         {/* Timesheet */}
-        <TableCell>{manhourFormatter.format(timesheetHours)}</TableCell>
+        <TableCell
+          sx={{
+            color: normalHoursExceeded ? "error.main" : undefined,
+          }}
+        >
+          <Box display="flex" gap={1} alignItems="center">
+            {manhourFormatter.format(timesheetHours)}
+            {normalHoursExceeded && (
+              <Tooltip
+                title={t(
+                  "The daily normal hours cannot be more than {{DAILY_NORMAL_MAX_HOURS}}. Please use other hours for exceeding hours.",
+                  {
+                    DAILY_NORMAL_MAX_HOURS,
+                  },
+                )}
+              >
+                <Info fontSize="small" />
+              </Tooltip>
+            )}
+          </Box>
+        </TableCell>
         {/* Leave total */}
         <TableCell
           sx={{
@@ -177,9 +199,9 @@ function DayRow<EntryTableProps>({
             {dailyTotalExceeded && (
               <Tooltip
                 title={t(
-                  "The daily total hours cannot be more than {{hours}}",
+                  "The daily total hours cannot be more than {{TIMESHEET_DAILY_MAX_HOURS}}",
                   {
-                    hours: TIMESHEET_DAILY_MAX_HOURS,
+                    TIMESHEET_DAILY_MAX_HOURS,
                   },
                 )}
               >
diff --git a/src/components/ErrorAlert/ErrorAlert.tsx b/src/components/ErrorAlert/ErrorAlert.tsx
new file mode 100644
index 0000000..192cd1b
--- /dev/null
+++ b/src/components/ErrorAlert/ErrorAlert.tsx
@@ -0,0 +1,28 @@
+import { Alert, AlertTitle, Box } from "@mui/material";
+import compact from "lodash/compact";
+import { useTranslation } from "react-i18next";
+
+interface Props {
+  errors: (string | undefined)[];
+}
+
+const ErrorAlert: React.FC<Props> = ({ errors }) => {
+  const { t } = useTranslation("common");
+
+  if (compact(errors).length === 0) return null;
+
+  return (
+    <Alert severity="error">
+      <AlertTitle>{t("There are some errors")}</AlertTitle>
+      <Box component="ul">
+        {errors.map((error, index) => (
+          <Box component="li" key={`${error}-${index}`}>
+            {error}
+          </Box>
+        ))}
+      </Box>
+    </Alert>
+  );
+};
+
+export default ErrorAlert;
diff --git a/src/components/ErrorAlert/index.ts b/src/components/ErrorAlert/index.ts
new file mode 100644
index 0000000..a92a0d9
--- /dev/null
+++ b/src/components/ErrorAlert/index.ts
@@ -0,0 +1 @@
+export { default } from "./ErrorAlert";
diff --git a/src/components/LeaveTable/LeaveEditModal.tsx b/src/components/LeaveTable/LeaveEditModal.tsx
index 2434e7a..3bbe857 100644
--- a/src/components/LeaveTable/LeaveEditModal.tsx
+++ b/src/components/LeaveTable/LeaveEditModal.tsx
@@ -101,9 +101,15 @@ const LeaveEditModal: React.FC<Props> = ({
           fullWidth
           {...register("inputHours", {
             setValueAs: (value) => roundToNearestQuarter(parseFloat(value)),
-            validate: (value) => 0 < value && value <= LEAVE_DAILY_MAX_HOURS,
+            validate: (value) =>
+              (0 < value && value <= LEAVE_DAILY_MAX_HOURS) ||
+              t(
+                "Input hours should be between 0 and {{LEAVE_DAILY_MAX_HOURS}}",
+                { LEAVE_DAILY_MAX_HOURS },
+              ),
           })}
           error={Boolean(formState.errors.inputHours)}
+          helperText={formState.errors.inputHours?.message}
         />
         <TextField
           label={t("Remark")}
diff --git a/src/components/TimesheetModal/TimesheetModal.tsx b/src/components/TimesheetModal/TimesheetModal.tsx
index 8214462..66ccd76 100644
--- a/src/components/TimesheetModal/TimesheetModal.tsx
+++ b/src/components/TimesheetModal/TimesheetModal.tsx
@@ -26,6 +26,12 @@ import FullscreenModal from "../FullscreenModal";
 import MobileTimesheetTable from "../TimesheetTable/MobileTimesheetTable";
 import useIsMobile from "@/app/utils/useIsMobile";
 import { HolidaysResult } from "@/app/api/holidays";
+import {
+  DAILY_NORMAL_MAX_HOURS,
+  TIMESHEET_DAILY_MAX_HOURS,
+  validateTimesheet,
+} from "@/app/api/timesheets/utils";
+import ErrorAlert from "../ErrorAlert";
 
 interface Props {
   isOpen: boolean;
@@ -77,6 +83,15 @@ const TimesheetModal: React.FC<Props> = ({
 
   const onSubmit = useCallback<SubmitHandler<RecordTimesheetInput>>(
     async (data) => {
+      const errors = validateTimesheet(data, leaveRecords, companyHolidays);
+      if (errors) {
+        Object.keys(errors).forEach((date) =>
+          formProps.setError(date, {
+            message: errors[date],
+          }),
+        );
+        return;
+      }
       const savedRecords = await saveTimesheet(data, username);
 
       const today = dayjs();
@@ -93,7 +108,7 @@ const TimesheetModal: React.FC<Props> = ({
       formProps.reset(newFormValues);
       onClose();
     },
-    [formProps, onClose, username],
+    [companyHolidays, formProps, leaveRecords, onClose, username],
   );
 
   const onCancel = useCallback(() => {
@@ -110,6 +125,20 @@ const TimesheetModal: React.FC<Props> = ({
     [onClose],
   );
 
+  const errorComponent = (
+    <ErrorAlert
+      errors={Object.keys(formProps.formState.errors).map((date) => {
+        const error = formProps.formState.errors[date]?.message;
+        return error
+          ? `${date}: ${t(error, {
+              TIMESHEET_DAILY_MAX_HOURS,
+              DAILY_NORMAL_MAX_HOURS,
+            })}`
+          : undefined;
+      })}
+    />
+  );
+
   const matches = useIsMobile();
 
   return (
@@ -138,6 +167,7 @@ const TimesheetModal: React.FC<Props> = ({
                   leaveRecords={leaveRecords}
                 />
               </Box>
+              {errorComponent}
               <CardActions sx={{ justifyContent: "flex-end" }}>
                 <Button
                   variant="outlined"
@@ -176,6 +206,7 @@ const TimesheetModal: React.FC<Props> = ({
               assignedProjects={assignedProjects}
               allProjects={allProjects}
               leaveRecords={leaveRecords}
+              errorComponent={errorComponent}
             />
           </Box>
         </FullscreenModal>
diff --git a/src/components/TimesheetTable/EntryInputTable.tsx b/src/components/TimesheetTable/EntryInputTable.tsx
index bccd9df..858032f 100644
--- a/src/components/TimesheetTable/EntryInputTable.tsx
+++ b/src/components/TimesheetTable/EntryInputTable.tsx
@@ -89,7 +89,8 @@ const EntryInputTable: React.FC<Props> = ({
     }, {});
   }, [assignedProjects]);
 
-  const { getValues, setValue } = useFormContext<RecordTimesheetInput>();
+  const { getValues, setValue, clearErrors } =
+    useFormContext<RecordTimesheetInput>();
   const currentEntries = getValues(day);
 
   const [entries, setEntries] = useState<TimeEntryRow[]>(currentEntries || []);
@@ -398,7 +399,8 @@ const EntryInputTable: React.FC<Props> = ({
           ...entry,
         })),
     ]);
-  }, [getValues, entries, setValue, day]);
+    clearErrors(day);
+  }, [getValues, entries, setValue, day, clearErrors]);
 
   const hasOutOfPlannedStages = entries.some(
     (entry) => entry.isPlanned !== undefined && !entry.isPlanned,
diff --git a/src/components/TimesheetTable/MobileTimesheetEntry.tsx b/src/components/TimesheetTable/MobileTimesheetEntry.tsx
index 96669da..a5eab75 100644
--- a/src/components/TimesheetTable/MobileTimesheetEntry.tsx
+++ b/src/components/TimesheetTable/MobileTimesheetEntry.tsx
@@ -51,7 +51,7 @@ const MobileTimesheetEntry: React.FC<Props> = ({
   const holiday = getHolidayForDate(date, companyHolidays);
   const isHoliday = holiday || dayJsObj.day() === 0 || dayJsObj.day() === 6;
 
-  const { watch, setValue } = useFormContext<RecordTimesheetInput>();
+  const { watch, setValue, clearErrors } = useFormContext<RecordTimesheetInput>();
   const currentEntries = watch(date);
 
   // Edit modal
@@ -70,13 +70,14 @@ const MobileTimesheetEntry: React.FC<Props> = ({
                 date,
                 currentEntries.filter((entry) => entry.id !== defaultValues.id),
               );
+              clearErrors(date);
               setEditModalOpen(false);
             }
           : undefined,
       });
       setEditModalOpen(true);
     },
-    [currentEntries, date, setValue],
+    [clearErrors, currentEntries, date, setValue],
   );
 
   const closeEditModal = useCallback(() => {
@@ -93,12 +94,13 @@ const MobileTimesheetEntry: React.FC<Props> = ({
             ...(e.id === existingEntry.id ? entry : e),
           })),
         );
+        clearErrors(date);
       } else {
         setValue(date, [...currentEntries, entry]);
       }
       setEditModalOpen(false);
     },
-    [currentEntries, date, setValue],
+    [clearErrors, currentEntries, date, setValue],
   );
 
   return (
diff --git a/src/components/TimesheetTable/MobileTimesheetTable.tsx b/src/components/TimesheetTable/MobileTimesheetTable.tsx
index f4c2cee..f09306f 100644
--- a/src/components/TimesheetTable/MobileTimesheetTable.tsx
+++ b/src/components/TimesheetTable/MobileTimesheetTable.tsx
@@ -14,6 +14,7 @@ interface Props {
   assignedProjects: AssignedProject[];
   leaveRecords: RecordLeaveInput;
   companyHolidays: HolidaysResult[];
+  errorComponent?: React.ReactNode;
 }
 
 const MobileTimesheetTable: React.FC<Props> = ({
@@ -21,6 +22,7 @@ const MobileTimesheetTable: React.FC<Props> = ({
   assignedProjects,
   leaveRecords,
   companyHolidays,
+  errorComponent,
 }) => {
   const { watch } = useFormContext<RecordTimesheetInput>();
   const currentInput = watch();
@@ -34,6 +36,7 @@ const MobileTimesheetTable: React.FC<Props> = ({
       timesheetEntries={currentInput}
       EntryComponent={MobileTimesheetEntry}
       entryComponentProps={{ allProjects, assignedProjects, companyHolidays }}
+      errorComponent={errorComponent}
     />
   );
 };