diff --git a/src/components/planning/PlanningsFormModal.tsx b/src/components/planning/PlanningsFormModal.tsx
index 71ebf43..abfdd97 100644
--- a/src/components/planning/PlanningsFormModal.tsx
+++ b/src/components/planning/PlanningsFormModal.tsx
@@ -1,13 +1,15 @@
-import { Col, DatePicker, Form, InputNumber, Modal, Row, Select } from "antd";
+import { Col, DatePicker, Form, InputNumber, Modal, notification, Row, Select } from "antd";
 import { FormComponentProps } from "antd/lib/form";
 import FormItem from "antd/lib/form/FormItem";
 import moment from "moment";
 import React from "react";
 import { isMomentDayAfterOrTheSameAsOtherDay } from "../../helpers/comparers";
+import { studentsPlannedFullyInRange, studentsPlannedPartiallyInRange, studentsPlannedInDay } from "../../helpers/filters";
 import { nameof } from "../../helpers/nameof";
 import { FormValidationTrigger } from "../../helpers/types";
 import { Department } from "../../models/Department";
 import { IStudentInternship, Student } from "../../models/Student";
+import { StudentsRepository } from "../../services/repositories/StudentsRepository";
 import styles from "./PlanningsFormModal.module.scss";
 
 interface IPlanningsFormModalProps {
@@ -225,10 +227,6 @@ class PlanningsFormModal extends React.Component<PlanningsFormModalProps, IPlann
         const fields: Array<keyof IStudentInternship> = ["startDate", "endDate", "hours", "departmentId"];
         this.props.form.validateFieldsAndScroll(fields, (errors, values) => {
             if (!errors) {
-                this.setState({
-                    isSubmitting: true,
-                });
-
                 const internship: IStudentInternship = {
                     startDate: values[nameof<IStudentInternship>("startDate")] as moment.Moment,
                     endDate: values[nameof<IStudentInternship>("endDate")] as moment.Moment,
@@ -236,13 +234,62 @@ class PlanningsFormModal extends React.Component<PlanningsFormModalProps, IPlann
                     departmentId: values[nameof<IStudentInternship>("departmentId") as string],
                 };
 
-                this.props.submitInternship(internship)
-                    .then(() => {
-                        this.handleClose();
+                const department = this.props.departments.find((dep) => dep.id === internship.departmentId);
+                if (department === undefined) {
+                    notification.warning({
+                        message: "Er ging iets fout, probeer later opnieuw",
+                    });
+                    return;
+                }
+
+                this.setState({
+                    isSubmitting: true,
+                });
+                StudentsRepository.getPlannedStudentsWithDepartment(department)
+                    .then((studentsWithDepartment) => {
+                        const students = studentsPlannedFullyInRange(studentsWithDepartment, internship.startDate, internship.endDate)
+                            .concat(studentsPlannedPartiallyInRange(studentsWithDepartment, internship.startDate, internship.endDate));
+
+                        const isCrossingTheCapacityLimits = department.totalCapacity <= department.getUsedCapacity(students);
+
+                        if (isCrossingTheCapacityLimits) {
+                            const intersectingDates: moment.Moment[] = [];
+                            for (const m = moment(internship.startDate); m.diff(internship.endDate, "days") <= 0; m.add(1, "day")) {
+                                if (department.totalCapacity <= department.getUsedCapacity(studentsPlannedInDay(students, m))) {
+                                    intersectingDates.push(moment(m));
+                                }
+                            }
+                            Modal.confirm({
+                                title: "Capaciteit overschreden",
+                                content: (
+                                    <React.Fragment>
+                                        <p>Er is minstens één geselecteerde dag waar de capaciteit voor <b>{department.name}</b> werd overschreden.</p>
+                                        <p>Bent u zeker dat u wilt verdergaan?</p>
+                                        <ul>
+                                            {intersectingDates.map((intersectingDate) => {
+                                                return <li key={intersectingDate.unix()}>{intersectingDate.format("DD MMMM YYYY")}</li>;
+                                            })}
+                                        </ul>
+                                    </React.Fragment>
+                                ),
+                                cancelText: "Terugkeren",
+                                onCancel: () => {
+                                    this.setState({
+                                        isSubmitting: false,
+                                    });
+                                },
+                                okText: "Toch toevoegen",
+                                onOk: () => {
+                                    this.doSubmit(internship);
+                                },
+                            });
+                        } else {
+                            this.doSubmit(internship);
+                        }
                     })
-                    .finally(() => {
-                        this.setState({
-                            isSubmitting: false,
+                    .catch(() => {
+                        notification.warning({
+                            message: "Er ging iets fout, probeer later opnieuw",
                         });
                     });
             }
@@ -255,6 +302,18 @@ class PlanningsFormModal extends React.Component<PlanningsFormModalProps, IPlann
             selectedEndDate: null,
         });
     }
+
+    private async doSubmit(internship: IStudentInternship): Promise<void> {
+        return this.props.submitInternship(internship)
+            .then(() => {
+                this.handleClose();
+            })
+            .finally(() => {
+                this.setState({
+                    isSubmitting: false,
+                });
+            });
+    }
 }
 
 const WrappedPlanningsFormModal = Form.create<PlanningsFormModalProps>()(PlanningsFormModal);
diff --git a/src/components/planning/PlanningsPage.tsx b/src/components/planning/PlanningsPage.tsx
index 6b41d8c..7f7b155 100644
--- a/src/components/planning/PlanningsPage.tsx
+++ b/src/components/planning/PlanningsPage.tsx
@@ -214,10 +214,7 @@ class PlanningsPage extends React.Component<PlanningsPageProps, IPlanningsPageSt
     private renderDateCell(date: moment.Moment): React.ReactNode {
         const plannedStudentsToday = studentsPlannedInDay(this.state.plannedStudents, date);
         const departmentsRows = this.state.departments.map((department) => {
-            const usedCapacity = plannedStudentsToday.filter((student) => {
-                return student.internship !== undefined
-                    && student.internship.departmentId === department.id;
-            }).length;
+            const usedCapacity = department.getUsedCapacity(plannedStudentsToday);
             const totalCapacity = department.totalCapacity;
             return (
                 <div key={department.id} className={styles.calendarTagContainer}>
diff --git a/src/components/schools/SchoolInternshipSummaryModal.tsx b/src/components/schools/SchoolInternshipSummaryModal.tsx
index f213319..6db6161 100644
--- a/src/components/schools/SchoolInternshipSummaryModal.tsx
+++ b/src/components/schools/SchoolInternshipSummaryModal.tsx
@@ -4,6 +4,7 @@ import FormItem from "antd/lib/form/FormItem";
 import moment from "moment";
 import React from "react";
 import { isMomentDayAfterOrTheSameAsOtherDay } from "../../helpers/comparers";
+import { studentsPlannedFullyInRange, studentsPlannedPartiallyInRange } from "../../helpers/filters";
 import { nameof } from "../../helpers/nameof";
 import { Department } from "../../models/Department";
 import { Education } from "../../models/Education";
@@ -78,23 +79,15 @@ class SchoolInternshipSummaryModal extends React.Component<SchoolInternshipSumma
     }
 
     public render(): React.ReactNode {
-        const studentsFullyInPeriod = this.state.studentsWithInternship.filter((student) => {
-            return this.state.selectedStartDate !== undefined && this.state.selectedEndDate !== undefined && student.internship !== undefined
-                && student.internship.startDate.isSameOrAfter(this.state.selectedStartDate)
-                && student.internship.endDate.isSameOrBefore(this.state.selectedEndDate);
-        });
-        const studentsNotFullyInPeriod = this.state.studentsWithInternship.filter((student) => {
-            return this.state.selectedStartDate !== undefined && this.state.selectedEndDate !== undefined && student.internship !== undefined
-                && ((student.internship.startDate.isBefore(this.state.selectedStartDate) && student.internship.endDate.isSameOrAfter(this.state.selectedStartDate))
-                    || (student.internship.endDate.isAfter(this.state.selectedEndDate) && student.internship.startDate.isSameOrBefore(this.state.selectedEndDate)));
-        });
+        const studentsFullyInPeriod = studentsPlannedFullyInRange(this.state.studentsWithInternship, this.state.selectedStartDate, this.state.selectedEndDate);
+        const studentsPartiallyInPeriod = studentsPlannedPartiallyInRange(this.state.studentsWithInternship, this.state.selectedStartDate, this.state.selectedEndDate);
 
-        const totalStudentsCount = studentsFullyInPeriod.length + studentsNotFullyInPeriod.length;
-        const totalInternshipDaysCount = [...studentsFullyInPeriod, ...studentsNotFullyInPeriod]
+        const totalStudentsCount = studentsFullyInPeriod.length + studentsPartiallyInPeriod.length;
+        const totalInternshipDaysCount = [...studentsFullyInPeriod, ...studentsPartiallyInPeriod]
             .map((student) => student.getInternshipNumberOfDaysInRange(this.state.selectedStartDate, this.state.selectedEndDate))
             .reduce((sum, days) => sum + days, 0);
 
-        const totalInternshipHoursCount = [...studentsFullyInPeriod, ...studentsNotFullyInPeriod]
+        const totalInternshipHoursCount = [...studentsFullyInPeriod, ...studentsPartiallyInPeriod]
             .map((student) => student.getInternshipNumberOfHoursInRange(this.state.selectedStartDate, this.state.selectedEndDate))
             .reduce((sum, hours) => sum + hours, 0);
 
@@ -173,7 +166,7 @@ class SchoolInternshipSummaryModal extends React.Component<SchoolInternshipSumma
                             <Card>
                                 {this.renderStudentsFullyInPeriod(studentsFullyInPeriod)}
                                 <br />
-                                {this.renderStudentsNotFullyInPeriod(studentsNotFullyInPeriod)}
+                                {this.renderStudentsNotFullyInPeriod(studentsPartiallyInPeriod)}
                             </Card>
                         </React.Fragment>
                     }
diff --git a/src/helpers/filters.ts b/src/helpers/filters.ts
index ec2f324..1cdab62 100644
--- a/src/helpers/filters.ts
+++ b/src/helpers/filters.ts
@@ -26,3 +26,19 @@ export function studentsPlannedInDay(students: Student[], date: moment.Moment):
             );
     });
 }
+
+export function studentsPlannedFullyInRange(students: Student[], from: moment.Moment | undefined, until: moment.Moment | undefined): Student[] {
+    return students.filter((student) => {
+        return from !== undefined && until !== undefined && student.internship !== undefined
+            && student.internship.startDate.isSameOrAfter(from)
+            && student.internship.endDate.isSameOrBefore(until);
+    });
+}
+
+export function studentsPlannedPartiallyInRange(students: Student[], from: moment.Moment | undefined, until: moment.Moment | undefined): Student[] {
+    return students.filter((student) => {
+        return from !== undefined && until !== undefined && student.internship !== undefined
+            && ((student.internship.startDate.isBefore(from) && student.internship.endDate.isSameOrAfter(from))
+                || (student.internship.endDate.isAfter(until) && student.internship.startDate.isSameOrBefore(until)));
+    });
+}
diff --git a/src/models/Department.ts b/src/models/Department.ts
index 42a8764..444a9f1 100644
--- a/src/models/Department.ts
+++ b/src/models/Department.ts
@@ -1,6 +1,7 @@
 import { IDepartment, IDepartmentEducationCapacity } from "../entities/IDepartment";
 import { Education } from "./Education";
 import { ModelBase } from "./ModelBase";
+import { Student } from "./Student";
 
 export class Department extends ModelBase<IDepartment> {
 
@@ -32,6 +33,13 @@ export class Department extends ModelBase<IDepartment> {
         return department;
     }
 
+    public getUsedCapacity(students: Student[]): number {
+        return students.filter((student) => {
+            return student.internship !== undefined
+                && student.internship.departmentId === this.id;
+        }).length;
+    }
+
     public getCapacityForEducation(education: Education): number {
         const educationCapacity = this.capacityPerEducation.find((capacity) => capacity.educationId === education.id);
         return educationCapacity === undefined