diff --git a/internal/checkin/checkin.handler.go b/internal/checkin/checkin.handler.go
index 44f6efb..a48a141 100644
--- a/internal/checkin/checkin.handler.go
+++ b/internal/checkin/checkin.handler.go
@@ -83,6 +83,18 @@ func (h *handlerImpl) Create(c context.Ctx) {
 		return
 	}
 
+	if body.StudentID != "" {
+		req := &dto.FindByEmailUserRequest{Email: body.StudentID + "@student.chula.ac.th"}
+		res, appErr := h.userSvc.FindByEmail(req)
+		if appErr != nil {
+			h.log.Named("Create").Error("FindOne: ", zap.Error(appErr))
+			c.ResponseError(appErr)
+			return
+		}
+
+		body.UserID = res.User.Id
+	}
+
 	req := &dto.CreateCheckInRequest{
 		Email:  body.Email,
 		UserID: body.UserID,
diff --git a/internal/dto/checkin.dto.go b/internal/dto/checkin.dto.go
index e74fbe4..212296f 100644
--- a/internal/dto/checkin.dto.go
+++ b/internal/dto/checkin.dto.go
@@ -10,9 +10,10 @@ type CheckIn struct {
 }
 
 type CreateCheckInRequest struct {
-	UserID string `json:"user_id"`
-	Email  string `json:"email"`
-	Event  string `json:"event"`
+	UserID    string `json:"user_id"`
+	StudentID string `json:"student_id"`
+	Email     string `json:"email"`
+	Event     string `json:"event"`
 }
 
 type CreateCheckInResponse struct {
diff --git a/internal/dto/user.dto.go b/internal/dto/user.dto.go
index 4dfac8b..f822a69 100644
--- a/internal/dto/user.dto.go
+++ b/internal/dto/user.dto.go
@@ -36,6 +36,14 @@ type FindOneUserResponse struct {
 	User *User `json:"user"`
 }
 
+type FindByEmailUserRequest struct {
+	Email string `json:"email" validate:"required,email"`
+}
+
+type FindByEmailUserResponse struct {
+	User *User `json:"user"`
+}
+
 type UpdateUserProfileBody struct {
 	Nickname    string `json:"nickname"`
 	Title       string `json:"title"`
diff --git a/internal/user/user.service.go b/internal/user/user.service.go
index 8b7a42f..8bd3b12 100644
--- a/internal/user/user.service.go
+++ b/internal/user/user.service.go
@@ -13,6 +13,7 @@ import (
 
 type Service interface {
 	FindOne(req *dto.FindOneUserRequest) (*dto.FindOneUserResponse, *apperror.AppError)
+	FindByEmail(req *dto.FindByEmailUserRequest) (*dto.FindByEmailUserResponse, *apperror.AppError)
 	UpdateProfile(req *dto.UpdateUserProfileRequest) (*dto.UpdateUserProfileResponse, *apperror.AppError)
 	UpdatePicture(req *dto.UpdateUserPictureRequest) (*dto.UpdateUserPictureResponse, *apperror.AppError)
 }
@@ -48,6 +49,23 @@ func (s *serviceImpl) FindOne(req *dto.FindOneUserRequest) (*dto.FindOneUserResp
 	}, nil
 }
 
+func (s *serviceImpl) FindByEmail(req *dto.FindByEmailUserRequest) (*dto.FindByEmailUserResponse, *apperror.AppError) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+
+	res, err := s.client.FindByEmail(ctx, &userProto.FindByEmailRequest{
+		Email: req.Email,
+	})
+	if err != nil {
+		s.log.Named("FindByEmail").Error("FindByEmail: ", zap.Error(err))
+		return nil, apperror.HandleServiceError(err)
+	}
+
+	return &dto.FindByEmailUserResponse{
+		User: ProtoToDto(res.User),
+	}, nil
+}
+
 func (s *serviceImpl) UpdateProfile(req *dto.UpdateUserProfileRequest) (*dto.UpdateUserProfileResponse, *apperror.AppError) {
 	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()