diff --git a/index.html b/index.html
index ee350c5..2bbfa4e 100644
--- a/index.html
+++ b/index.html
@@ -21,6 +21,7 @@
   <div data-section="Edit" data-alt="e">
     <button data-alt="u" data-button="edit:undo" disabled>Undo</button>
     <button data-alt="r" data-button="edit:redo" disabled>Redo</button>
+    <button data-alt="e" data-toggle="planner:resize" data-toggled="false">Resize mode</button>
     <button data-toggle="dev-mode:toggle" data-toggled="false">Developer mode</button>
   </div>
   <div data-section="Select" data-alt="s">
@@ -124,7 +125,7 @@
   </section>
 </aside>
 <footer>
-  <div>pre-alpha 1.3</div>
+  <div>pre-alpha 1.4</div>
   <div>
     <a href="https://discord.gg/Eq72HwPqfg">Discord server</a>
   </div>
diff --git a/scripts/dev-mode.js b/scripts/dev-mode.js
index ec79d5a..21948f3 100644
--- a/scripts/dev-mode.js
+++ b/scripts/dev-mode.js
@@ -41,4 +41,6 @@ registerLoadCallback(() => {
   awaitEvent("config:end").then(() => {
     void loadExampleFile("Pandora's Fission Reactor");
   });
+
+  queueMicrotask(() => emitEvent("dev-mode:end"));
 });
diff --git a/scripts/files.js b/scripts/files.js
index 3b21289..1811b3b 100644
--- a/scripts/files.js
+++ b/scripts/files.js
@@ -52,6 +52,8 @@ export async function loadFile(data, name) {
   if (!data.designs) throw new UserError("File must contain a list of designs!");
   if (data.designs.length === 0) throw new UserError("Fils must contain at least one design!");
 
+  emitEvent("fileLoad:start");
+
   let design = data.designs[0];
   if (data.designs.length > 1) {
     const prepChoice = awaitEvent("fileLoad:chooseDesign:choice");
@@ -74,6 +76,8 @@ export async function loadFile(data, name) {
     getPlannerDom().dataset.name = name;
   }
 
+  emitEvent("fileLoad:end");
+
   console.log("load file", data);
 }
 
diff --git a/scripts/main.js b/scripts/main.js
index 3444931..4fc4d54 100644
--- a/scripts/main.js
+++ b/scripts/main.js
@@ -12,6 +12,7 @@ import "./js-utils.js"
 import "./menu-bar.js";
 import "./ncpf-utils.js";
 import "./planner.js";
+import "./planner-resize.js";
 import "./recipe-selector.js";
 import "./resize-menus.js";
 import "./solver.js";
diff --git a/scripts/planner-resize.js b/scripts/planner-resize.js
new file mode 100644
index 0000000..aa76588
--- /dev/null
+++ b/scripts/planner-resize.js
@@ -0,0 +1,200 @@
+import { registerLoadCallback } from "./main.js";
+import { awaitEvent, listenTo } from "./events.js";
+import {
+  createPlannerCell,
+  createPlannerPlane,
+  getPlannerDom,
+  getPlannerMultiblockSize, getPlannerMultiblockType,
+  maxMultiblockSize
+} from "./planner.js";
+import { DomList } from "./dom-list.js";
+
+registerLoadCallback(() => {
+  listenTo("planner:resize", e => {
+    if (e.detail.state) {
+      initializeResize();
+    } else {
+      cleanUpResize();
+    }
+  });
+
+  awaitEvent("dev-mode:end").then(async () => {
+    await awaitEvent("fileLoad:end");
+    initializeResize();
+  });
+});
+
+function createButton({ axis, n, add, topLeft }) {
+  const div = document.createElement("div");
+  div.innerText = add ? "+" : "-";
+  if (axis === "y") {
+    div.classList.add(`planner--resize--${add ? "add" : "remove"}-layer`);
+    if (!add) {
+      div.addEventListener("mouseenter", () => highlight(axis, n, add));
+      div.addEventListener("mouseleave", () => highlight(null));
+    }
+  } else {
+    div.classList.add(`planner--resize--${add ? "add" : "remove"}-${axis}`);
+    div.classList.add(`planner--resize--${topLeft ? "top-left" : "bottom-right"}`);
+    div.style.setProperty(`--${axis}`, `${n}`);
+    div.addEventListener("mouseenter", () => highlight(axis, n, add));
+    div.addEventListener("mouseleave", () => highlight(null));
+  }
+  div.addEventListener("click", e => resize(axis, n, add, e));
+  return div;
+}
+
+function highlight(axis, n, add) {
+  const planner = getPlannerDom();
+  const resizes = [...planner.querySelectorAll(":scope > .planner--resize")];
+  if (!axis) {
+    resizes.forEach(r => {
+      r.querySelectorAll(":scope > .planner--resize--highlight").forEach(e => r.removeChild(e));
+    });
+    return;
+  }
+  if (axis === "y") {
+    const div = document.createElement("div");
+    div.classList.add("planner--resize--highlight", `planner--resize--highlight__remove-layer`);
+    resizes[n].appendChild(div);
+    return;
+  }
+  resizes.forEach(r => {
+    const div = document.createElement("div");
+    div.classList.add("planner--resize--highlight", `planner--resize--highlight__${add ? "add" : "remove"}-${axis}`);
+    div.style.setProperty(`--${axis}`, `${n}`);
+    r.appendChild(div);
+  });
+}
+
+function resize(axis, n, add, e) {
+  const planner = getPlannerDom();
+  const size = getPlannerMultiblockSize();
+  if (!add) {
+    if (axis === "y") {
+      const resizes = planner.querySelectorAll(`:scope > .planner--resize`);
+      planner.removeChild(resizes[n]);
+      size[1]--;
+    } else {
+      const tiles = planner.querySelectorAll(`[data-${axis}="${n}"]`);
+      const tileGroups = Object.values(Object.groupBy(tiles, t => t.parentElement.dataset.y));
+      for (const tg of tileGroups) {
+        const parent = tg[0].parentElement;
+        tg.forEach(t => parent.removeChild(t));
+      }
+      size[axis === "x" ? 0 : 2]--;
+    }
+  } else {
+    if (axis === "y") {
+      const list = new DomList(planner);
+      const plane = list.makeItem();
+      createPlannerPlane(plane, 0, null);
+      const parentPlane = document.createElement("div");
+      parentPlane.classList.add("planner--resize");
+      parentPlane.appendChild(plane)
+      const nextSibling = planner.querySelector(`:scope > .planner--resize[data-y="${n+1}"]`);
+      planner.insertBefore(parentPlane, nextSibling);
+      size[1]++;
+    } else {
+      const tiles = planner.querySelectorAll(`[data-${axis}="${n}"]`);
+      const tileGroups = Object.values(Object.groupBy(tiles, t => t.parentElement.dataset.y));
+      for (const tg of tileGroups) {
+        const parent = tg[0].parentElement;
+        const grid = new DomList(parent);
+        tg.forEach(t => {
+          const cell = grid.makeItem();
+          createPlannerCell(cell, 0, 0, 0, -1);
+          parent.insertBefore(cell, axis === "x" ? t : tg[0]);
+        });
+      }
+      size[axis === "x" ? 0 : 2]++;
+    }
+  }
+  fixPlannerNumbering();
+  cleanUpResize();
+  initializeResize();
+}
+
+function initializeResize() {
+  const planner = getPlannerDom();
+  const size = getPlannerMultiblockSize();
+  const type = getPlannerMultiblockType();
+  const grids = [...planner.querySelectorAll(":scope > .grid")];
+  grids.forEach((grid, gridIndex) => {
+    const casing = gridIndex === 0 || gridIndex === grids.length - 1;
+
+    const removedGrid = planner.removeChild(grid);
+    const newDiv = document.createElement("div");
+    newDiv.classList.add("planner--resize");
+    newDiv.style.setProperty("--width", `${size[0]}`);
+    newDiv.style.setProperty("--height", `${size[2]}`);
+    newDiv.dataset.y = gridIndex.toString(10);
+    if (casing) {
+      newDiv.dataset.casing = "";
+    }
+
+    if (!casing && size[1] > maxMultiblockSize[type][1]) {
+      newDiv.appendChild(createButton({ axis: "y", add: false, n: gridIndex }));
+    }
+    if (!casing) {
+      for (let x = 0; x < size[0] - 1 && size[0] < maxMultiblockSize[type][0]; x++) {
+        newDiv.appendChild(createButton({ axis: "x", add: true, n: x+1, topLeft: true }));
+      }
+      for (let x = 0; x < size[0] - 2 && size[0] > maxMultiblockSize[type][0]; x++) {
+        newDiv.appendChild(createButton({ axis: "x", add: false, n: x+1, topLeft: true }));
+      }
+      for (let z = 0; z < size[2] - 1 && size[2] < maxMultiblockSize[type][2]; z++) {
+        newDiv.appendChild(createButton({ axis: "z", add: true, n: z+1, topLeft: true }));
+      }
+      for (let z = 0; z < size[2] - 2 && size[2] > maxMultiblockSize[type][2]; z++) {
+        newDiv.appendChild(createButton({ axis: "z", add: false, n: z+1, topLeft: true }));
+      }
+    }
+
+    newDiv.appendChild(removedGrid);
+    planner.appendChild(newDiv);
+
+    if (!casing) {
+      for (let x = 0; x < size[0] - 1 && size[0] < maxMultiblockSize[type][0]; x++) {
+        newDiv.appendChild(createButton({ axis: "x", add: true, n: x+1, topLeft: false }));
+      }
+      for (let x = 0; x < size[0] - 2 && size[0] > maxMultiblockSize[type][0]; x++) {
+        newDiv.appendChild(createButton({ axis: "x", add: false, n: x+1, topLeft: false }));
+      }
+      for (let z = 0; z < size[2] - 1 && size[2] < maxMultiblockSize[type][2]; z++) {
+        newDiv.appendChild(createButton({ axis: "z", add: true, n: z+1, topLeft: false }));
+      }
+      for (let z = 0; z < size[2] - 2 && size[2] > maxMultiblockSize[type][2]; z++) {
+        newDiv.appendChild(createButton({ axis: "z", add: false, n: z+1, topLeft: false }));
+      }
+    }
+
+    planner.appendChild(newDiv);
+
+    if (gridIndex !== grids.length - 1 && size[1] < maxMultiblockSize[type][1]) {
+      planner.appendChild(createButton({ axis: "y", add: true, n: gridIndex }));
+    }
+  });
+}
+
+function cleanUpResize() {
+  const planner = getPlannerDom();
+  planner.replaceChildren(...planner.querySelectorAll(":scope > .planner--resize > .grid"), ...planner.querySelectorAll(":scope > template"));
+}
+
+function fixPlannerNumbering() {
+  const planner = getPlannerDom();
+  const size = getPlannerMultiblockSize();
+  const grids = planner.querySelectorAll(":scope > .planner--resize > .grid");
+  grids.forEach(grid => {
+    grid.style.setProperty("--width", size[0].toString(10));
+    const tiles = [...grid.querySelectorAll("[data-tile]")];
+    for (let z = 0; z < size[2]; z++) {
+      for (let x = 0; x < size[0]; x++) {
+        const tile = tiles.shift();
+        tile.dataset.x = x.toString(10);
+        tile.dataset.z = z.toString(10);
+      }
+    }
+  });
+}
diff --git a/scripts/planner.js b/scripts/planner.js
index 678292d..a47c36b 100644
--- a/scripts/planner.js
+++ b/scripts/planner.js
@@ -19,9 +19,12 @@ const casingDefault = false; // hidden by default
 
 const defaultMultiblockSize = [9, 7, 9]; // width (screen x), height (xy grids), depth (screen y)
 const defaultMultiblockType = "nuclearcraft:overhaul_sfr";
-const maxMultiblockSize = {
+export const maxMultiblockSize = {
   ["nuclearcraft:overhaul_sfr"]: [26, 26, 26],
 }
+export const minMultiblockSize = {
+  ["nuclearcraft:overhaul_sfr"]: [3, 3, 3],
+}
 
 let suppressHover = false;
 let multiblockSize = [...defaultMultiblockSize];
@@ -107,44 +110,50 @@ function buildPlanner(textures) {
 
   for (let y = 0; y < multiblockSize[1]; y++) {
     const item = list.makeItem();
-    item.style.setProperty("--width", multiblockSize[0]);
-    item.dataset.y = y.toString(10);
-    if (y === 0 || y === multiblockSize[1] - 1) {
-      item.dataset.casing = "";
-    }
-    item.addEventListener("mousemove", retainTooltipHover);
-    const grid = new DomList(item);
-    grid.clear();
-    for (let z = 0; z < multiblockSize[2]; z++) {
-      for (let x = 0; x < multiblockSize[0]; x++) {
-        const texture = textures ? textures[x][y][z] : -1;
-        if (textures && !texture) {
-          console.log(x, y, z, textures);
-        }
-        const cell = grid.makeItem();
-        cell.dataset.x = x.toString(10);
-        cell.dataset.y = y.toString(10);
-        cell.dataset.z = z.toString(10);
-        cell.dataset.tile = texture.toString(10);
-        if (x === 0 || x === multiblockSize[0] - 1
-            || y === 0 || y === multiblockSize[1] - 1
-            || z === 0 || z === multiblockSize[2] - 1) {
-          cell.dataset.casing = "";
-        }
-        cell.dataset.tooltip = "auto";
-        cell.appendChild(makeAtlasImage(texture));
-        cell.addEventListener("mouseenter", cellHoverEvent);
-        cell.addEventListener("mouseleave", cellHoverEvent);
-        cell.addEventListener("mousedown", cellClickEvent);
-        cell.addEventListener("mouseenter", cellClickEvent);
-        cell.addEventListener("mouseleave", cellClickEvent);
-        cell.addEventListener("contextmenu", cellClickEvent);
-        grid.addItem(cell);
-      }
-    }
+    createPlannerPlane(item, y, textures);
     list.addItem(item);
   }
 }
+export function createPlannerPlane(dom, y, textures) {
+  dom.style.setProperty("--width", multiblockSize[0]);
+  dom.dataset.y = y.toString();
+  if (y === 0 || y === multiblockSize[1] - 1) {
+    dom.dataset.casing = "";
+  }
+  dom.addEventListener("mousemove", retainTooltipHover);
+  const grid = new DomList(dom);
+  grid.clear();
+  for (let z = 0; z < multiblockSize[2]; z++) {
+    for (let x = 0; x < multiblockSize[0]; x++) {
+      const texture = textures ? textures[x][y][z] : -1;
+      if (textures && !texture) {
+        console.log(x, y, z, textures);
+      }
+      const cell = grid.makeItem();
+      createPlannerCell(cell, x, y, z, texture);
+      grid.addItem(cell);
+    }
+  }
+}
+export function createPlannerCell(dom, x, y, z, texture) {
+  dom.dataset.x = x.toString();
+  dom.dataset.y = y.toString();
+  dom.dataset.z = z.toString();
+  dom.dataset.tile = texture.toString();
+  if (x === 0 || x === multiblockSize[0] - 1
+      || y === 0 || y === multiblockSize[1] - 1
+      || z === 0 || z === multiblockSize[2] - 1) {
+    dom.dataset.casing = "";
+  }
+  dom.dataset.tooltip = "auto";
+  dom.appendChild(makeAtlasImage(texture));
+  dom.addEventListener("mouseenter", cellHoverEvent);
+  dom.addEventListener("mouseleave", cellHoverEvent);
+  dom.addEventListener("mousedown", cellClickEvent);
+  dom.addEventListener("mouseenter", cellClickEvent);
+  dom.addEventListener("mouseleave", cellClickEvent);
+  dom.addEventListener("contextmenu", cellClickEvent);
+}
 
 function cellHoverEvent(e) {
   if (suppressHover) return;
diff --git a/style.css b/style.css
index 9311047..6c9cb94 100644
--- a/style.css
+++ b/style.css
@@ -240,7 +240,7 @@ input:not([type="checkbox"]):not([type="radio"]):not([type="file"]) {
             calc(var(--scale-factor) * var(--size-x, var(--default-size)) * 0.4);
     background-color: var(--highlight-color, #f808);
 }
-[data-casing="hide"] #planner > * {
+[data-casing="hide"] #planner .grid {
     --width-override: calc(var(--width) - 2);
 }
 [data-casing="hide"] [data-casing] {
@@ -254,6 +254,129 @@ input:not([type="checkbox"]):not([type="radio"]):not([type="file"]) {
     outline: none;
 }
 
+.planner--resize {
+    --resize-width: var(--width);
+    --resize-height: var(--height);
+    --resize-offset: 2;
+    display: grid;
+    grid-template-columns: repeat(calc(var(--resize-width) * 2 + 4), calc(var(--scale-factor) * var(--default-size) / 2));
+    grid-template-rows: repeat(calc(var(--resize-height) * 2 + 4), calc(var(--scale-factor) * var(--default-size) / 2));
+    margin: 0.5rem;
+}
+[data-casing="hide"] .planner--resize {
+    --resize-offset: 0;
+    grid-template-columns: repeat(calc(var(--resize-width) * 2), calc(var(--scale-factor) * var(--default-size) / 2));
+    grid-template-rows: repeat(calc(var(--resize-height) * 2), calc(var(--scale-factor) * var(--default-size) / 2));
+}
+.planner--resize--remove-layer {
+    grid-column: 1;
+    grid-row: 1;
+}
+.planner--resize--add-x {
+    grid-column: calc(var(--x) * 2 + 0 + var(--resize-offset)) / calc(var(--x) * 2 + 2 + var(--resize-offset));
+}
+.planner--resize--remove-x {
+    grid-column: calc(var(--x) * 2 + 1 + var(--resize-offset)) / calc(var(--x) * 2 + 3 + var(--resize-offset));
+}
+.planner--resize--add-x.planner--resize--top-left {
+    grid-row: 1;
+}
+.planner--resize--remove-x.planner--resize--top-left {
+    grid-row: 2;
+}
+.planner--resize--add-x.planner--resize--bottom-right {
+    grid-row: calc(var(--resize-height) * 2 - 0 + var(--resize-offset) * 2);
+}
+.planner--resize--remove-x.planner--resize--bottom-right {
+    grid-row: calc(var(--resize-height) * 2 - 1 + var(--resize-offset) * 2);
+}
+.planner--resize--add-z {
+    grid-row: calc(var(--z) * 2 + 0 + var(--resize-offset)) / calc(var(--z) * 2 + 2 + var(--resize-offset));
+}
+.planner--resize--remove-z {
+    grid-row: calc(var(--z) * 2 + 1 + var(--resize-offset)) / calc(var(--z) * 2 + 3 + var(--resize-offset));
+}
+.planner--resize--add-z.planner--resize--top-left {
+    grid-column: 1;
+}
+.planner--resize--remove-z.planner--resize--top-left {
+    grid-column: 2;
+}
+.planner--resize--add-z.planner--resize--bottom-right {
+    grid-column: calc(var(--resize-width) * 2 - 0 + var(--resize-offset) * 2);
+}
+.planner--resize--remove-z.planner--resize--bottom-right {
+    grid-column: calc(var(--resize-width) * 2 - 1 + var(--resize-offset) * 2);
+}
+.planner--resize > .grid {
+    grid-column: 3 / calc(var(--resize-width) * 2 - 1);
+    grid-row: 3 / calc(var(--resize-height) * 2 - 1);
+    margin: 0;
+}
+.planner--resize--add-layer {
+    width: calc(var(--scale-factor) * var(--default-size));
+    margin: 0.5rem;
+}
+.planner--resize--add-layer, .planner--resize--add-x, .planner--resize--add-z,
+        .planner--resize--remove-layer, .planner--resize--remove-x, .planner--resize--remove-z {
+    display: flex;
+    justify-content: center;
+    align-items: center;
+
+    cursor: pointer;
+    user-select: none;
+}
+.planner--resize--add-layer, .planner--resize--add-x, .planner--resize--add-z {
+    background: var(--resize-add-bg, #4f88);
+}
+.planner--resize--add-layer:hover, .planner--resize--add-x:hover, .planner--resize--add-z:hover {
+    background: var(--resize-add-bg-hover, #4f8);
+}
+.planner--resize--remove-layer, .planner--resize--remove-x, .planner--resize--remove-z {
+    background: var(--resize-remove-bg, #f888);
+}
+.planner--resize--remove-layer:hover, .planner--resize--remove-x:hover, .planner--resize--remove-z:hover {
+    background: var(--resize-remove-bg-hover, #f88);
+}
+.planner--resize--add-x, .planner--resize--remove-x {
+    margin: 0 0.125rem;
+}
+.planner--resize--add-z, .planner--resize--remove-z {
+    margin: 0.125em 0;
+}
+.planner--resize--highlight {
+    z-index: 2;
+}
+.planner--resize--highlight__add-x {
+    background: var(--resize-add-bg-highlight, #4f88);
+    margin: 0 25%;
+    grid-row: 3 / -3;
+    grid-column: calc(var(--x) * 2 + 0 + var(--resize-offset)) / calc(var(--x) * 2 + 2 + var(--resize-offset));
+}
+.planner--resize--highlight__remove-x {
+    background: var(--resize-remove-bg-highlight, #f888);
+    grid-row: 3 / -3;
+    grid-column: calc(var(--x) * 2 + 1 + var(--resize-offset)) / calc(var(--x) * 2 + 3 + var(--resize-offset));
+}
+.planner--resize--highlight__add-z {
+    background: var(--resize-add-bg-highlight, #4f88);
+    /*margin: 25% 0;*/
+    margin-top: calc(var(--scale-factor) * var(--default-size) / 4);
+    height: 50%;
+    grid-row: calc(var(--z) * 2 + 0 + var(--resize-offset)) / calc(var(--z) * 2 + 2 + var(--resize-offset));
+    grid-column: 3 / -3;
+}
+.planner--resize--highlight__remove-z {
+    background: var(--resize-remove-bg-highlight, #f888);
+    grid-row: calc(var(--z) * 2 + 1 + var(--resize-offset)) / calc(var(--z) * 2 + 3 + var(--resize-offset));
+    grid-column: 3 / -3;
+}
+.planner--resize--highlight__remove-layer {
+    background: var(--resize-remove-bg-highlight, #f888);
+    grid-row: 3 / -3;
+    grid-column: 3 / -3;
+}
+
 #planner .atlas-air {
     outline: calc(var(--scale-factor) * 0.5px) solid var(--cell-empty-outline-color, #ccc);
     outline-offset: calc(var(--scale-factor) * -0.5px);