diff --git a/src/App.tsx b/src/App.tsx
index 856e45a..c8e415f 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -53,11 +53,15 @@ function migrateQOfficeState(state: QOfficeState): QOfficeState {
     state.word.id === initialState.word.id &&
     sampleWordHtml.includes("Ключевой результат") &&
     !state.word.html.includes("Ключевой результат");
+  const needsDeckSlideSize = !state.deck.slideSize;
 
   let changed = false;
   if (needsSampleWordColor) {
     changed = true;
   }
+  if (needsDeckSlideSize) {
+    changed = true;
+  }
   const messages = state.mail.messages.map((message) => {
     if (!launchChecklistAttachments || message.id !== "mail-1" || (message.attachments?.length ?? 0) > 0) {
       return message;
@@ -117,7 +121,7 @@ function migrateQOfficeState(state: QOfficeState): QOfficeState {
         ...state,
         word: needsSampleWordColor ? { ...state.word, html: sampleWordHtml } : state.word,
         workbook: { ...state.workbook, sheets },
-        deck: { ...state.deck, slides },
+        deck: { ...state.deck, slideSize: state.deck.slideSize ?? initialState.deck.slideSize ?? "wide", slides },
         mail: { ...state.mail, messages }
       }
     : state;
diff --git a/src/data/sampleData.ts b/src/data/sampleData.ts
index 59481d7..993f294 100644
--- a/src/data/sampleData.ts
+++ b/src/data/sampleData.ts
@@ -109,6 +109,7 @@ export const initialState: QOfficeState = {
     title: "Дорожная карта.qpptx",
     updatedAt: new Date().toISOString(),
     activeSlideId: "slide-1",
+    slideSize: "wide",
     slides: [
       {
         id: "slide-1",
diff --git a/src/features/qpowerpoint/QPowerPoint.test.tsx b/src/features/qpowerpoint/QPowerPoint.test.tsx
index 4450120..0f85951 100644
--- a/src/features/qpowerpoint/QPowerPoint.test.tsx
+++ b/src/features/qpowerpoint/QPowerPoint.test.tsx
@@ -55,6 +55,21 @@ describe("QPowerPoint", () => {
     expect(nextDeck.slides[0].images?.[0].hyperlink).toBe("https://example.com/updated-logo");
   });
 
+  it("переключает размер слайда презентации", () => {
+    const onChange = vi.fn();
+    const view = render(<QPowerPoint deck={deckWithLinkedImage()} onChange={onChange} />);
+    const slideSizeSelect = view.container.querySelector('select[aria-label="Размер слайда"]') as HTMLSelectElement;
+    const canvas = view.container.querySelector(".slide-canvas") as HTMLElement;
+
+    expect(slideSizeSelect).toHaveValue("wide");
+    expect(canvas.style.aspectRatio).toBe("13.333 / 7.5");
+
+    fireEvent.change(slideSizeSelect, { target: { value: "standard" } });
+
+    const nextDeck = onChange.mock.calls[onChange.mock.calls.length - 1]?.[0] as SlideDeck;
+    expect(nextDeck.slideSize).toBe("standard");
+  });
+
   it("переключает начертание текста слайда", () => {
     const onChange = vi.fn();
     const view = render(<QPowerPoint deck={deckWithLinkedImage()} onChange={onChange} />);
diff --git a/src/features/qpowerpoint/QPowerPoint.tsx b/src/features/qpowerpoint/QPowerPoint.tsx
index 37d7eea..4d29784 100644
--- a/src/features/qpowerpoint/QPowerPoint.tsx
+++ b/src/features/qpowerpoint/QPowerPoint.tsx
@@ -1,7 +1,7 @@
 import { useRef, useState } from "react";
 import type { CSSProperties } from "react";
 import { AlignCenter, AlignLeft, AlignRight, Bold, Copy, Download, EyeOff, FileText, FileUp, Image as ImageIcon, Italic, Link, List, ListOrdered, ListX, Palette, Plus, Save, Strikethrough, Trash2, Underline } from "lucide-react";
-import type { Slide, SlideDeck, SlideImage, SlideListStyle, SlideTextAlign, SlideTransition } from "../../types";
+import type { Slide, SlideDeck, SlideImage, SlideListStyle, SlideSizeId, SlideTextAlign, SlideTransition } from "../../types";
 import { downloadBlobFile, downloadTextFile } from "../../utils/download";
 import { exportPptxBlob, importPptxFile } from "../../io/powerPointOffice";
 import { replaceFileExtension } from "../../io/fileHelpers";
@@ -58,8 +58,20 @@ const slideTransitionOptions: Array<{ value: SlideTransition | ""; label: string
   { value: "wipe", label: "Шторка" }
 ];
 
-const slideWidthInches = 13.333;
-const slideHeightInches = 7.5;
+const slideSizeOptions: Array<{ id: SlideSizeId; label: string; width: number; height: number }> = [
+  { id: "wide", label: "Широкий 16:9", width: 13.333, height: 7.5 },
+  { id: "standard", label: "Стандартный 4:3", width: 10, height: 7.5 }
+];
+
+type SlideDimensions = { width: number; height: number };
+
+function normalizedSlideSizeId(value?: SlideSizeId): SlideSizeId {
+  return value === "standard" ? "standard" : "wide";
+}
+
+function slideDimensions(value?: SlideSizeId): SlideDimensions {
+  return slideSizeOptions.find((option) => option.id === normalizedSlideSizeId(value)) ?? slideSizeOptions[0];
+}
 
 function readFileAsDataUrl(file: File) {
   return new Promise<string>((resolve, reject) => {
@@ -99,18 +111,21 @@ function roundSlideNumber(value: number) {
   return Math.round(value * 10) / 10;
 }
 
-function slideImageStyle(image: SlideImage) {
+function slideImageStyle(image: SlideImage, dimensions: SlideDimensions) {
   return {
-    left: `${(image.x / slideWidthInches) * 100}%`,
-    top: `${(image.y / slideHeightInches) * 100}%`,
-    width: `${(image.width / slideWidthInches) * 100}%`,
-    height: `${(image.height / slideHeightInches) * 100}%`
+    left: `${(image.x / dimensions.width) * 100}%`,
+    top: `${(image.y / dimensions.height) * 100}%`,
+    width: `${(image.width / dimensions.width) * 100}%`,
+    height: `${(image.height / dimensions.height) * 100}%`
   };
 }
 
-function slideCanvasStyle(slide: Slide) {
+function slideCanvasStyle(slide: Slide, dimensions: SlideDimensions): CSSProperties {
   const backgroundColor = normalizedHexColor(slide.backgroundColor);
-  return backgroundColor ? { background: `#${backgroundColor}` } : undefined;
+  return {
+    aspectRatio: `${dimensions.width} / ${dimensions.height}`,
+    ...(backgroundColor ? { background: `#${backgroundColor}` } : {})
+  };
 }
 
 function slideTextStyle(
@@ -167,6 +182,7 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
   const activeSlide = deck.slides.find((slide) => slide.id === deck.activeSlideId) ?? deck.slides[0];
   const activeImages = activeSlide.images ?? [];
   const selectedImage = activeImages.find((image) => image.id === selectedImageId);
+  const activeSlideSize = slideDimensions(deck.slideSize);
 
   function updateSlide(nextSlide: Slide) {
     onChange({
@@ -266,6 +282,7 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
         ...deck,
         title: imported.title,
         activeSlideId: imported.slides[0]?.id ?? "slide-1",
+        slideSize: imported.slideSize ?? deck.slideSize ?? "wide",
         slides: imported.slides.length > 0 ? imported.slides : deck.slides
       });
     } catch (error) {
@@ -289,8 +306,8 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
         id: `slide-image-${Date.now()}`,
         src,
         alt: file.name,
-        x: roundSlideNumber(Math.max(0.4, slideWidthInches - size.width - 0.9)),
-        y: roundSlideNumber(Math.max(1.4, slideHeightInches - size.height - 0.8)),
+        x: roundSlideNumber(Math.max(0.4, activeSlideSize.width - size.width - 0.9)),
+        y: roundSlideNumber(Math.max(1.4, activeSlideSize.height - size.height - 0.8)),
         ...size
       };
 
@@ -466,6 +483,20 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
                 ))}
               </select>
             </label>
+            <label className="office-field">
+              <span>Размер</span>
+              <select
+                value={normalizedSlideSizeId(deck.slideSize)}
+                onChange={(event) => onChange({ ...deck, slideSize: event.target.value as SlideSizeId })}
+                aria-label="Размер слайда"
+              >
+                {slideSizeOptions.map((option) => (
+                  <option key={option.id} value={option.id}>
+                    {option.label}
+                  </option>
+                ))}
+              </select>
+            </label>
             <div className="slide-background-swatches" aria-label="Фон слайда">
               <Palette size={16} aria-hidden="true" />
               {backgroundColorSwatches.map((swatch) => (
@@ -783,10 +814,10 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
                     <input
                       type="number"
                       min="0"
-                      max={slideWidthInches}
+                      max={activeSlideSize.width}
                       step="0.1"
                       value={selectedImage.x}
-                      onChange={(event) => updateSelectedImageNumber("x", event.target.value, slideWidthInches)}
+                      onChange={(event) => updateSelectedImageNumber("x", event.target.value, activeSlideSize.width)}
                     />
                   </label>
                   <label>
@@ -794,10 +825,10 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
                     <input
                       type="number"
                       min="0"
-                      max={slideHeightInches}
+                      max={activeSlideSize.height}
                       step="0.1"
                       value={selectedImage.y}
-                      onChange={(event) => updateSelectedImageNumber("y", event.target.value, slideHeightInches)}
+                      onChange={(event) => updateSelectedImageNumber("y", event.target.value, activeSlideSize.height)}
                     />
                   </label>
                   <label>
@@ -805,10 +836,10 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
                     <input
                       type="number"
                       min="0.1"
-                      max={slideWidthInches}
+                      max={activeSlideSize.width}
                       step="0.1"
                       value={selectedImage.width}
-                      onChange={(event) => updateSelectedImageNumber("width", event.target.value, slideWidthInches)}
+                      onChange={(event) => updateSelectedImageNumber("width", event.target.value, activeSlideSize.width)}
                     />
                   </label>
                   <label>
@@ -816,10 +847,10 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
                     <input
                       type="number"
                       min="0.1"
-                      max={slideHeightInches}
+                      max={activeSlideSize.height}
                       step="0.1"
                       value={selectedImage.height}
-                      onChange={(event) => updateSelectedImageNumber("height", event.target.value, slideHeightInches)}
+                      onChange={(event) => updateSelectedImageNumber("height", event.target.value, activeSlideSize.height)}
                     />
                   </label>
                 </div>
@@ -854,13 +885,13 @@ export function QPowerPoint({ deck, onChange }: QPowerPointProps) {
           </label>
         </div>
 
-        <div className={`slide-canvas theme-${activeSlide.theme}`} style={slideCanvasStyle(activeSlide)}>
+        <div className={`slide-canvas theme-${activeSlide.theme}`} style={slideCanvasStyle(activeSlide, activeSlideSize)}>
           {activeImages.map((image) => (
             <button
               key={image.id}
               type="button"
               className={`slide-image-object ${image.id === selectedImageId ? "is-selected" : ""}`}
-              style={slideImageStyle(image)}
+              style={slideImageStyle(image, activeSlideSize)}
               onClick={() => setSelectedImageId(image.id)}
               title={image.alt || "Изображение"}
               aria-label={image.alt || "Изображение слайда"}
diff --git a/src/io/powerPointOffice.test.ts b/src/io/powerPointOffice.test.ts
index 79a5904..743fbc2 100644
--- a/src/io/powerPointOffice.test.ts
+++ b/src/io/powerPointOffice.test.ts
@@ -7,6 +7,7 @@ import {
   listSlidePaths,
   normalizeWhitespace,
   presentationSlidePaths,
+  presentationSlideSize,
   relationshipTargetByType,
   resolvePptTarget
 } from "./powerPointOffice";
@@ -81,6 +82,30 @@ describe("powerPointOffice helpers", () => {
     ]);
   });
 
+  it("читает размер слайда из presentation.xml", () => {
+    expect(
+      presentationSlideSize({
+        presentation: {
+          sldSz: { cx: "12192000", cy: "6858000" }
+        }
+      })
+    ).toBe("wide");
+    expect(
+      presentationSlideSize({
+        presentation: {
+          sldSz: { "@_cx": "9144000", "@_cy": "6858000" }
+        }
+      })
+    ).toBe("standard");
+    expect(
+      presentationSlideSize({
+        presentation: {
+          sldSz: { cx: "9144000", cy: "5143500" }
+        }
+      })
+    ).toBeUndefined();
+  });
+
   it("разрешает относительные targets заметок от части слайда", () => {
     expect(resolvePptTarget("ppt/slides", "../notesSlides/notesSlide7.xml")).toBe("ppt/notesSlides/notesSlide7.xml");
     expect(
@@ -104,7 +129,7 @@ describe("powerPointOffice helpers", () => {
     const zip = new JSZip();
     zip.file(
       "ppt/presentation.xml",
-      `<p:presentation xmlns:p="http://schemas.openxmlformats.org/presentationml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"><p:sldIdLst><p:sldId id="256" r:id="rId2"/><p:sldId id="255" r:id="rId1"/></p:sldIdLst></p:presentation>`
+      `<p:presentation xmlns:p="http://schemas.openxmlformats.org/presentationml/2006/main" xmlns:r="http://schemas.openxmlformats.org/officeDocument/2006/relationships"><p:sldSz cx="9144000" cy="6858000"/><p:sldIdLst><p:sldId id="256" r:id="rId2"/><p:sldId id="255" r:id="rId1"/></p:sldIdLst></p:presentation>`
     );
     zip.file(
       "ppt/_rels/presentation.xml.rels",
@@ -125,6 +150,7 @@ describe("powerPointOffice helpers", () => {
     const imported = await importPptxFile(new File([blob], "Дорожная карта.pptx", { type: blob.type }));
 
     expect(imported.slides.map((slide) => slide.title)).toEqual(["Первый по порядку", "Первый файл"]);
+    expect(imported.slideSize).toBe("standard");
     expect(imported.slides[0].subtitle).toBe("Содержимое первого слайда");
     expect(imported.slides[0].notes).toBe("Заметка докладчика");
   });
@@ -772,6 +798,28 @@ describe("powerPointOffice helpers", () => {
     });
   });
 
+  it("экспортирует и переимпортирует стандартный размер слайда PPTX 4:3", async () => {
+    const blob = await exportPptxBlob({
+      title: "Standard.pptx",
+      slideSize: "standard",
+      slides: [
+        {
+          id: "slide-1",
+          title: "Standard",
+          subtitle: "4:3",
+          notes: "",
+          theme: "classic"
+        }
+      ]
+    });
+    const zip = await JSZip.loadAsync(await blob.arrayBuffer());
+    const presentationXml = (await zip.file("ppt/presentation.xml")?.async("string")) ?? "";
+    const reimported = await importPptxFile(new File([blob], "Standard.pptx", { type: blob.type }));
+
+    expect(presentationXml).toContain('<p:sldSz cx="9144000" cy="6858000"/>');
+    expect(reimported.slideSize).toBe("standard");
+  });
+
   it("нормализует пробелы в импортированном тексте", () => {
     expect(normalizeWhitespace("  Строка\tс \n пробелами  ")).toBe("Строка с пробелами");
   });
diff --git a/src/io/powerPointOffice.ts b/src/io/powerPointOffice.ts
index a706430..3ebe79b 100644
--- a/src/io/powerPointOffice.ts
+++ b/src/io/powerPointOffice.ts
@@ -1,13 +1,15 @@
-import type { Slide, SlideImage, SlideListStyle, SlideTextAlign } from "../types";
+import type { Slide, SlideImage, SlideListStyle, SlideSizeId, SlideTextAlign } from "../types";
 import { officeTitleFromFileName, PPTX_MIME_TYPE, readOfficeFileAsArrayBuffer } from "./fileHelpers";
 
 export interface ImportedPowerPointDeck {
   title: string;
+  slideSize?: SlideSizeId;
   slides: Slide[];
 }
 
 export interface ExportablePowerPointDeck {
   title: string;
+  slideSize?: SlideSizeId;
   slides: Slide[];
 }
 
@@ -47,6 +49,10 @@ const imageRelationshipType = "http://schemas.openxmlformats.org/officeDocument/
 const hyperlinkRelationshipType = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink";
 const emuPerInch = 914400;
 const slideTransitions = ["fade", "push", "wipe"] as const;
+const slideSizeLayouts: Record<SlideSizeId, { width: number; height: number; cx: number; cy: number; pptxLayout: string }> = {
+  wide: { width: 13.333, height: 7.5, cx: 12192000, cy: 6858000, pptxLayout: "LAYOUT_WIDE" },
+  standard: { width: 10, height: 7.5, cx: 9144000, cy: 6858000, pptxLayout: "LAYOUT_4x3" }
+};
 const themeColors: Record<Slide["theme"], { background: string; title: string; subtitle: string }> = {
   classic: { background: "FFFFFF", title: "202124", subtitle: "3C4043" },
   ocean: { background: "EAF6FF", title: "075985", subtitle: "0F766E" },
@@ -65,6 +71,7 @@ export async function importPptxFile(file: File): Promise<ImportedPowerPointDeck
   const presentationXml = await readOptionalParsedXml(zip, parser, "ppt/presentation.xml");
   const presentationRelationshipsXml = await readOptionalParsedXml(zip, parser, "ppt/_rels/presentation.xml.rels");
   const slidePaths = listSlidePaths(zip, presentationXml, presentationRelationshipsXml);
+  const slideSize = presentationSlideSize(presentationXml);
 
   if (slidePaths.length === 0) {
     throw new Error("В файле PowerPoint не найдены слайды.");
@@ -126,7 +133,7 @@ export async function importPptxFile(file: File): Promise<ImportedPowerPointDeck
     })
   );
 
-  return { title, slides };
+  return { title, ...(slideSize ? { slideSize } : {}), slides };
 }
 
 export async function exportPptxBlob(deck: ExportablePowerPointDeck): Promise<Blob> {
@@ -147,8 +154,10 @@ export async function exportPptxBlob(deck: ExportablePowerPointDeck): Promise<Bl
     };
     write: (options: { outputType: "blob" | "arraybuffer" }) => Promise<Blob | ArrayBuffer>;
   };
+  const slideSize = normalizedSlideSizeId(deck.slideSize);
+  const slideLayout = slideSizeLayouts[slideSize];
 
-  pptx.layout = "LAYOUT_WIDE";
+  pptx.layout = slideLayout.pptxLayout;
   pptx.author = "QOffice";
   pptx.company = "QOffice";
   pptx.subject = "Экспорт QPowerPoint";
@@ -196,7 +205,7 @@ export async function exportPptxBlob(deck: ExportablePowerPointDeck): Promise<Bl
     slide.addText(sourceSlide.title || "Без заголовка", {
       x: 0.7,
       y: 0.65,
-      w: 11.9,
+      w: Math.max(1, slideLayout.width - 1.4),
       h: 0.75,
       fontFace: titleFontFamily,
       fontSize: titleFontSize,
@@ -213,8 +222,8 @@ export async function exportPptxBlob(deck: ExportablePowerPointDeck): Promise<Bl
     slide.addText(sourceSlide.subtitle || "", {
       x: 0.75,
       y: 1.65,
-      w: 11.5,
-      h: 4.35,
+      w: Math.max(1, slideLayout.width - 1.5),
+      h: Math.max(1, slideLayout.height - 3.15),
       fontFace: subtitleFontFamily,
       fontSize: subtitleFontSize,
       ...(subtitleAlign ? { align: subtitleAlign } : {}),
@@ -411,6 +420,19 @@ export function presentationSlidePaths(presentationXml: unknown, presentationRel
   return slideIds.map((id) => relationshipTargets[id]).filter((target): target is string => Boolean(target));
 }
 
+export function presentationSlideSize(presentationXml: unknown): SlideSizeId | undefined {
+  const slideSize = childRecord(childRecord(presentationXml, "presentation"), "sldSz");
+  const cx = numberAttribute(slideSize, "cx");
+  const cy = numberAttribute(slideSize, "cy");
+  if (!cx || !cy) {
+    return undefined;
+  }
+
+  return Object.entries(slideSizeLayouts).find(([, layout]) => Math.abs(cx - layout.cx) <= 5000 && Math.abs(cy - layout.cy) <= 5000)?.[0] as
+    | SlideSizeId
+    | undefined;
+}
+
 export function relationshipTargetsById(relationshipsXml: unknown, type?: string, sourcePartPath = "ppt/presentation.xml"): Record<string, string> {
   const relationships = childRecord(relationshipsXml, "Relationships");
   const targets: Record<string, string> = {};
@@ -467,6 +489,10 @@ export function normalizeWhitespace(value: string): string {
   return value.replace(/\s+/g, " ").trim();
 }
 
+function normalizedSlideSizeId(value?: SlideSizeId): SlideSizeId {
+  return value === "standard" ? "standard" : "wide";
+}
+
 function normalizeTextWithLineBreaks(value: string): string {
   return value
     .split("\n")
diff --git a/src/types.ts b/src/types.ts
index 9da032b..96aabbf 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -97,11 +97,14 @@ export interface SheetChart {
   valueRange: string;
 }
 
+export type SlideSizeId = "wide" | "standard";
+
 export interface SlideDeck {
   id: string;
   title: string;
   updatedAt: string;
   activeSlideId: string;
+  slideSize?: SlideSizeId;
   slides: Slide[];
 }