diff --git a/client/src/App.tsx b/client/src/App.tsx
index 88e4c9c..8f492a8 100644
--- a/client/src/App.tsx
+++ b/client/src/App.tsx
@@ -360,8 +360,7 @@ function App() {
           <Alert variant={'primary'}>
             Poslední změny:
             <ul>
-              <li>Oprava parsování restaurace U Motlíků, pokud neexistuje nabídka pro první den v týdnu</li>
-              <li>Oprava parsování restaurace Sladovnická, pokud nabídka nezačíná pondělím</li>
+              <li>Základní pizza kalkulačka (v menu)</li>
             </ul>
           </Alert>
           {dayIndex != null &&
diff --git a/client/src/components/Header.tsx b/client/src/components/Header.tsx
index e941782..166f379 100644
--- a/client/src/components/Header.tsx
+++ b/client/src/components/Header.tsx
@@ -7,6 +7,7 @@ import FeaturesVotingModal from "./modals/FeaturesVotingModal";
 import { FeatureRequest } from "../types";
 import { errorHandler } from "../api/Api";
 import { getFeatureVotes, updateFeatureVote } from "../api/VotingApi";
+import PizzaCalculatorModal from "./modals/PizzaCalculatorModal";
 
 
 export default function Header() {
@@ -14,6 +15,7 @@ export default function Header() {
     const bank = useBank();
     const [bankModalOpen, setBankModalOpen] = useState<boolean>(false);
     const [votingModalOpen, setVotingModalOpen] = useState<boolean>(false);
+    const [pizzaModalOpen, setPizzaModalOpen] = useState<boolean>(false);
     const [featureVotes, setFeatureVotes] = useState<FeatureRequest[]>([]);
 
     useEffect(() => {
@@ -32,6 +34,10 @@ export default function Header() {
         setVotingModalOpen(false);
     }
 
+    const closePizzaModal = () => {
+        setPizzaModalOpen(false);
+    }
+
     const isValidInteger = (str: string) => {
         str = str.trim();
         if (!str) {
@@ -108,11 +114,14 @@ export default function Header() {
                 <NavDropdown align="end" title={auth?.login} id="basic-nav-dropdown">
                     <NavDropdown.Item onClick={() => setBankModalOpen(true)}>Nastavit číslo účtu</NavDropdown.Item>
                     <NavDropdown.Item onClick={() => setVotingModalOpen(true)}>Hlasovat o nových funkcích</NavDropdown.Item>
+                    <NavDropdown.Item onClick={() => setPizzaModalOpen(true)}>Pizza kalkulačka</NavDropdown.Item>
+                    <NavDropdown.Divider />
                     <NavDropdown.Item onClick={auth?.logout}>Odhlásit se</NavDropdown.Item>
                 </NavDropdown>
             </Nav>
         </Navbar.Collapse>
         <BankAccountModal isOpen={bankModalOpen} onClose={closeBankModal} onSave={saveBankAccount} />
         <FeaturesVotingModal isOpen={votingModalOpen} onClose={closeVotingModal} onChange={saveFeatureVote} initialValues={featureVotes} />
+        <PizzaCalculatorModal isOpen={pizzaModalOpen} onClose={closePizzaModal} />
     </Navbar>
 }
\ No newline at end of file
diff --git a/client/src/components/modals/PizzaCalculatorModal.tsx b/client/src/components/modals/PizzaCalculatorModal.tsx
new file mode 100644
index 0000000..e66b120
--- /dev/null
+++ b/client/src/components/modals/PizzaCalculatorModal.tsx
@@ -0,0 +1,141 @@
+import { useRef, useState } from "react";
+import { Modal, Button, Row, Col } from "react-bootstrap"
+
+type Props = {
+    isOpen: boolean,
+    onClose: () => void,
+}
+
+type Result = {
+    pizza1?: {
+        diameter?: number,
+        area?: number,
+        pricePerM?: number,
+    },
+    pizza2?: {
+        diameter?: number,
+        area?: number,
+        pricePerM?: number,
+    }
+    choice?: number,
+    ratio?: number,
+    diameterDiff?: number,
+}
+
+/** Modální dialog pro výpočet výhodnosti pizzy. */
+export default function PizzaCalculatorModal({ isOpen, onClose }: Props) {
+    const diameter1Ref = useRef<HTMLInputElement>(null);
+    const price1Ref = useRef<HTMLInputElement>(null);
+    const diameter2Ref = useRef<HTMLInputElement>(null);
+    const price2Ref = useRef<HTMLInputElement>(null);
+
+    const [result, setResult] = useState<Result | null>(null);
+
+    const recalculate = () => {
+        const r: Result = { ...result }
+
+        // 1. pizza
+        if (diameter1Ref.current?.value) {
+            const diameter1 = parseInt(diameter1Ref.current?.value);
+            if (!r.pizza1) {
+                r.pizza1 = {};
+            }
+            if (diameter1 && diameter1 > 0) {
+                r.pizza1.diameter = diameter1;
+                r.pizza1.area = Math.PI * Math.pow(diameter1 / 2, 2);
+                if (price1Ref.current?.value) {
+                    const price1 = parseInt(price1Ref.current?.value);
+                    if (price1) {
+                        r.pizza1.pricePerM = price1 / r.pizza1.area;
+                    } else {
+                        r.pizza1.pricePerM = undefined;
+                    }
+                }
+            } else {
+                r.pizza1.area = undefined;
+            }
+        }
+
+        // 2. pizza
+        if (diameter2Ref.current?.value) {
+            const diameter2 = parseInt(diameter2Ref.current?.value);
+            if (!r.pizza2) {
+                r.pizza2 = {};
+            }
+            if (diameter2 && diameter2 > 0) {
+                r.pizza2.diameter = diameter2;
+                r.pizza2.area = Math.PI * Math.pow(diameter2 / 2, 2);
+                if (price2Ref.current?.value) {
+                    const price2 = parseInt(price2Ref.current?.value);
+                    if (price2) {
+                        r.pizza2.pricePerM = price2 / r.pizza2.area;
+                    } else {
+                        r.pizza2.pricePerM = undefined;
+                    }
+                }
+            } else {
+                r.pizza2.area = undefined;
+            }
+        }
+
+        // Srovnání
+        if (r.pizza1?.pricePerM && r.pizza2?.pricePerM && r.pizza1.diameter && r.pizza2.diameter) {
+            r.choice = r.pizza1.pricePerM < r.pizza2.pricePerM ? 1 : 2;
+            const bigger = r.pizza1.pricePerM > r.pizza2.pricePerM ? r.pizza1.pricePerM : r.pizza2.pricePerM;
+            const smaller = r.pizza1.pricePerM < r.pizza2.pricePerM ? r.pizza1.pricePerM : r.pizza2.pricePerM;
+            r.ratio = (bigger / smaller) - 1;
+            r.diameterDiff = Math.abs(r.pizza1.diameter - r.pizza2.diameter);
+        } else {
+            r.choice = undefined;
+            r.ratio = undefined;
+            r.diameterDiff = undefined;
+        }
+        setResult(r);
+    }
+
+    const close = () => {
+        setResult(null);
+        onClose();
+    }
+
+    return <Modal show={isOpen} onHide={onClose}>
+        <Modal.Header closeButton>
+            <Modal.Title>Pizza kalkulačka</Modal.Title>
+        </Modal.Header>
+        <Modal.Body>
+            <p>Zadejte parametry pizzy pro jejich srovnání.</p>
+            <Row>
+                <Col size="6">
+                    <input className="mb-3" ref={diameter1Ref} type="number" step="1" min="1" placeholder="Průměr 1. pizzy (cm)" onChange={recalculate} />
+                </Col>
+                <Col size="6">
+                    <input className="mb-3" ref={diameter2Ref} type="number" step="1" min="1" placeholder="Průměr 2. pizzy (cm)" onChange={recalculate} />
+                </Col>
+            </Row>
+            <Row>
+                <Col size="6">
+                    <input className="mb-3" ref={price1Ref} type="number" min="1" placeholder="Cena 1. pizzy (Kč)" onChange={recalculate} />
+                </Col>
+                <Col size="6">
+                    <input className="mb-3" ref={price2Ref} type="number" min="1" placeholder="Cena 2. pizzy (Kč)" onChange={recalculate} />
+                </Col>
+            </Row>
+            <Row>
+                <Col size="6">
+                    {result?.pizza1?.area && <p>Plocha: <b>{Math.round(result.pizza1.area * 10) / 10}</b> cm²</p>}
+                    {result?.pizza1?.pricePerM && <p>Cena za m²: <b>{Math.round(result.pizza1.pricePerM * 1000000) / 100}</b> Kč</p>}
+                </Col>
+                <Col size="6">
+                    {result?.pizza2?.area && <p>Plocha: <b>{Math.round(result.pizza2.area * 10) / 10}</b> cm²</p>}
+                    {result?.pizza2?.pricePerM && <p>Cena za m²: <b>{Math.round(result.pizza2.pricePerM * 1000000) / 100}</b> Kč</p>}
+                </Col>
+            </Row>
+            {result?.choice && result?.ratio && result?.ratio > 0 && result?.diameterDiff != null && <p><b>{result.choice}. pizza</b> je zhruba o <b>{Math.round(result.ratio * 1000) / 10}%</b> výhodnější než {result.choice === 1 ? "2" : "1"}. pizza.</p> || ''}
+        </Modal.Body>
+        <Modal.Footer>
+            <Button variant="primary" onClick={close}>
+                Zavřít
+            </Button>
+        </Modal.Footer>
+    </Modal>
+}
\ No newline at end of file