diff --git a/A00_Common/spreadsheet/spreadsheet_clipboard.ts b/A00_Common/spreadsheet/spreadsheet_clipboard.ts
index 46a6b556e..d0d7796e6 100644
--- a/A00_Common/spreadsheet/spreadsheet_clipboard.ts
+++ b/A00_Common/spreadsheet/spreadsheet_clipboard.ts
@@ -14,6 +14,7 @@
 
 import { showToast } from "@ui/ui_template_elements";
 import { colName, parseA1, parseRange, toA1 } from "./spreadsheet_address";
+import { clipWholeToUsed } from "./spreadsheet_grid_cells";
 import { formatValue } from "./spreadsheet_numfmt";
 import { moveFormula, r1c1ToA1 } from "./spreadsheet_refshift";
 import { st } from "./spreadsheet_text";
@@ -425,15 +426,15 @@ function notifyNoFormulaOnce(): void {
 
 /* ── 화면 붙임 — copy · cut · paste 사건 ────────────────────────────────── */
 
+/** 복사 · 잘라내기 범위 — 행 · 열 · 전체 선택은 쓴 최외곽까지만(99-4) */
 function activeRange(ctx: SpreadsheetContext): CellRange {
-  return (
-    ctx.selection.범위[0] ?? {
-      r0: ctx.selection.활성.r,
-      c0: ctx.selection.활성.c,
-      r1: ctx.selection.활성.r,
-      c1: ctx.selection.활성.c,
-    }
-  );
+  const range = ctx.selection.범위[0] ?? {
+    r0: ctx.selection.활성.r,
+    c0: ctx.selection.활성.c,
+    r1: ctx.selection.활성.r,
+    c1: ctx.selection.활성.c,
+  };
+  return clipWholeToUsed(ctx.sheet(), range);
 }
 
 function rangesOverlap(a: CellRange, b: CellRange): boolean {
@@ -539,8 +540,7 @@ export function attachClipboard(ctx: SpreadsheetContext): PartHandle {
   /** 마지막 잘라내기 — 같은 문서에 붙이면 칸을 옮김(그 칸을 가리키던 식도 따라감 · 엑셀) */
   let cut: PendingCut | null = null;
 
-  function write(ev: ClipboardEvent, prefix = ""): void {
-    const range = activeRange(ctx);
+  function write(ev: ClipboardEvent, range: CellRange, prefix = ""): void {
     const { html, text } = blockToClipboard(ctx.book, ctx.selection.시트, range, (r, c) =>
       ctx.engine.value(ctx.selection.시트, r, c),
     );
@@ -552,7 +552,7 @@ export function attachClipboard(ctx: SpreadsheetContext): PartHandle {
   function onCopy(ev: ClipboardEvent): void {
     if (ctx.editor.editing()) return;
     cut = null;
-    write(ev);
+    write(ev, activeRange(ctx));
   }
 
   function onCut(ev: ClipboardEvent): void {
@@ -563,7 +563,7 @@ export function attachClipboard(ctx: SpreadsheetContext): PartHandle {
     for (const [a1, cell] of Object.entries(sheet.칸))
       if (inside(range, a1)) cells[a1] = structuredClone(cell);
     const token = Math.random().toString(36).slice(2);
-    write(ev, `<!--aislo-cut:${token}-->`);
+    write(ev, range, `<!--aislo-cut:${token}-->`);
     cut = { token, sheet: sheet.id, range, cells };
     ctx.dispatch({ 종류: "내용지움", 시트: sheet.id, 범위: [range] });
   }
diff --git a/A00_Common/spreadsheet/spreadsheet_grid_cells.ts b/A00_Common/spreadsheet/spreadsheet_grid_cells.ts
index bd26acf42..a98943c5c 100644
--- a/A00_Common/spreadsheet/spreadsheet_grid_cells.ts
+++ b/A00_Common/spreadsheet/spreadsheet_grid_cells.ts
@@ -81,10 +81,10 @@ function toScalar(value: number | string | boolean): Scalar {
   return typeof value === "number" ? toFrac(value) : value;
 }
 
-/** 시트에 실제 쓰인 자리 + 여유(엑셀 최대 자리까지 다 쓰지 않음 — 스크롤판 스페이서를 적당히 둠). */
-export function computeExtent(sheet: Sheet): { rows: number; cols: number } {
-  let maxR = 0;
-  let maxC = 0;
+/** 시트에 실제 쓰인 최외곽 — 줄 수 · 칸 수(0 = 빈 시트). 칸 · 행 높이 · 열 폭 · 병합을 모두 침. */
+export function usedExtent(sheet: Sheet): { rows: number; cols: number } {
+  let maxR = -1;
+  let maxC = -1;
   for (const key of Object.keys(sheet.칸)) {
     const addr = parseA1(key);
     if (!addr) continue;
@@ -99,9 +99,30 @@ export function computeExtent(sheet: Sheet): { rows: number; cols: number } {
     maxR = Math.max(maxR, range.r1);
     maxC = Math.max(maxC, range.c1);
   }
+  return { rows: maxR + 1, cols: maxC + 1 };
+}
+
+/** 시트에 실제 쓰인 자리 + 여유(엑셀 최대 자리까지 다 쓰지 않음 — 스크롤판 스페이서를 적당히 둠). */
+export function computeExtent(sheet: Sheet): { rows: number; cols: number } {
+  const used = usedExtent(sheet);
   return {
-    rows: Math.min(MAX_ROWS, Math.max(maxR + 100, 200)),
-    cols: Math.min(MAX_COLS, Math.max(maxC + 20, 60)),
+    rows: Math.min(MAX_ROWS, Math.max(used.rows + 99, 200)),
+    cols: Math.min(MAX_COLS, Math.max(used.cols + 19, 60)),
+  };
+}
+
+/** 행 머리 · 열 머리 · 전체로 고른 범위를 쓴 최외곽까지만 줄임(복사 · 잘라내기 — 99-4). 그 밖 범위는 그대로.
+ * 쓴 곳이 범위 앞이면 한 줄 · 한 칸만 남김(빈 시트 = 빈 칸 하나). */
+export function clipWholeToUsed(sheet: Sheet, range: CellRange): CellRange {
+  const wholeRows = range.c0 === 0 && range.c1 === MAX_COLS - 1;
+  const wholeCols = range.r0 === 0 && range.r1 === MAX_ROWS - 1;
+  if (!wholeRows && !wholeCols) return range;
+  const used = usedExtent(sheet);
+  return {
+    r0: range.r0,
+    c0: range.c0,
+    r1: wholeCols ? Math.max(range.r0, Math.min(range.r1, used.rows - 1)) : range.r1,
+    c1: wholeRows ? Math.max(range.c0, Math.min(range.c1, used.cols - 1)) : range.c1,
   };
 }
 
diff --git a/resources/tester/spreadsheet/spreadsheet_clip_used_entry.ts b/resources/tester/spreadsheet/spreadsheet_clip_used_entry.ts
new file mode 100644
index 000000000..0ae9c5465
--- /dev/null
+++ b/resources/tester/spreadsheet/spreadsheet_clip_used_entry.ts
@@ -0,0 +1,65 @@
+/* 행 · 열 · 전체 고른 복사 = 쓴 최외곽까지(99-4) 시험 진입 — vite --ssr 로 번들해 Node 로 돌림.
+ * 결과 = JSON {pass, fail, failures} 한 줄(`test_spreadsheet_clip_used.py` 가 읽음) */
+import { blockToClipboard } from "../../../A00_Common/spreadsheet/spreadsheet_clipboard";
+import {
+  clipWholeToUsed,
+  usedExtent,
+} from "../../../A00_Common/spreadsheet/spreadsheet_grid_cells";
+import { MAX_COLS, MAX_ROWS } from "../../../A00_Common/spreadsheet/spreadsheet_types";
+import type { CellRange, Workbook } from "../../../A00_Common/spreadsheet/spreadsheet_types";
+
+let pass = 0;
+const failures: string[] = [];
+const eq = (name: string, got: unknown, want: unknown): void => {
+  if (JSON.stringify(got) === JSON.stringify(want)) pass += 1;
+  else failures.push(`${name}: ${JSON.stringify(got)} ≠ ${JSON.stringify(want)}`);
+};
+
+const book = (칸: Record<string, { 값: number }>): Workbook =>
+  ({
+    종류: "통합문서",
+    판: 1,
+    열: "t",
+    서식: [{}],
+    시트: [{ id: "s1", 이름: "면적산출", 칸 }],
+    활성: "s1",
+  }) as unknown as Workbook;
+
+const used = book({ A1: { 값: 1 }, C7: { 값: 2 }, B12: { 값: 3 } }); // 12 줄 · 3 칸
+const empty = book({});
+const sheet = used.시트[0];
+const R = (r0: number, c0: number, r1: number, c1: number): CellRange => ({ r0, c0, r1, c1 });
+const lines = (b: Workbook, rg: CellRange): { rows: number; cols: number } => {
+  const t = blockToClipboard(b, "s1", rg, () => null).text.split("\r\n");
+  return { rows: t.length, cols: t[0].split("\t").length };
+};
+
+eq("usedExtent", usedExtent(sheet), { rows: 12, cols: 3 });
+eq("usedExtent 빈 시트", usedExtent(empty.시트[0]), { rows: 0, cols: 0 });
+eq("열 머리 A:C", clipWholeToUsed(sheet, R(0, 0, MAX_ROWS - 1, 2)), R(0, 0, 11, 2));
+eq("열 머리 줄 수", lines(used, clipWholeToUsed(sheet, R(0, 0, MAX_ROWS - 1, 0))), {
+  rows: 12,
+  cols: 1,
+});
+eq("행 머리 3행", clipWholeToUsed(sheet, R(2, 0, 2, MAX_COLS - 1)), R(2, 0, 2, 2));
+eq("행 머리 칸 수", lines(used, clipWholeToUsed(sheet, R(2, 0, 2, MAX_COLS - 1))), {
+  rows: 1,
+  cols: 3,
+});
+eq("전체", clipWholeToUsed(sheet, R(0, 0, MAX_ROWS - 1, MAX_COLS - 1)), R(0, 0, 11, 2));
+eq("전체 줄 · 칸", lines(used, clipWholeToUsed(sheet, R(0, 0, MAX_ROWS - 1, MAX_COLS - 1))), {
+  rows: 12,
+  cols: 3,
+});
+eq("쓴 곳 밖 열 머리 Z", clipWholeToUsed(sheet, R(0, 25, MAX_ROWS - 1, 25)), R(0, 25, 11, 25));
+eq("쓴 곳 밖 행 머리 500", clipWholeToUsed(sheet, R(499, 0, 499, MAX_COLS - 1)), R(499, 0, 499, 2));
+eq(
+  "빈 시트 전체",
+  clipWholeToUsed(empty.시트[0], R(0, 0, MAX_ROWS - 1, MAX_COLS - 1)),
+  R(0, 0, 0, 0),
+);
+eq("빈 시트 복사 글", blockToClipboard(empty, "s1", R(0, 0, 0, 0), () => null).text.trim(), "");
+eq("보통 범위는 그대로", clipWholeToUsed(sheet, R(0, 0, 999, 5)), R(0, 0, 999, 5));
+eq("단일 칸", clipWholeToUsed(sheet, R(4, 4, 4, 4)), R(4, 4, 4, 4));
+
+console.log(JSON.stringify({ pass, fail: failures.length, failures }));
diff --git a/resources/tester/test_spreadsheet_clip_used.py b/resources/tester/test_spreadsheet_clip_used.py
new file mode 100644
index 000000000..ac2ecbf8f
--- /dev/null
+++ b/resources/tester/test_spreadsheet_clip_used.py
@@ -0,0 +1,57 @@
+"""스프레드시트 행 · 열 · 전체 고른 복사 = 쓴 최외곽까지(PLAN 99-4).
+
+`clipWholeToUsed`(순수) · `blockToClipboard` 를 vite `--ssr` 로 번들해 Node 로 돌림 —
+열 머리 → 쓴 줄 수만 · 행 머리 → 쓴 칸 수만 · 전체 → 최외곽 사각형 · 빈 시트 → 빈 복사 · 보통 범위는 그대로.
+"""
+
+from __future__ import annotations
+
+import json
+import shutil
+import subprocess
+import tempfile
+from pathlib import Path
+
+import pytest
+
+ROOT = Path(__file__).resolve().parents[2]
+ENTRY = ROOT / "resources" / "tester" / "spreadsheet" / "spreadsheet_clip_used_entry.ts"
+VITE = ROOT / "config" / "node_modules" / "vite" / "bin" / "vite.js"
+
+
+@pytest.mark.skipif(shutil.which("node") is None, reason="node 가 없음")
+def test_고른_복사_쓴_범위까지():
+    with tempfile.TemporaryDirectory(prefix="spreadsheet_clip_used_") as outdir:
+        entry_rel = "../" + str(ENTRY.relative_to(ROOT)).replace("\\", "/")
+        build = subprocess.run(
+            [
+                "node",
+                str(VITE),
+                "build",
+                "--configLoader",
+                "runner",
+                "--ssr",
+                entry_rel,
+                "--outDir",
+                outdir,
+            ],
+            cwd=str(ROOT),
+            capture_output=True,
+            text=True,
+            encoding="utf-8",
+            errors="replace",
+            timeout=120,
+        )
+        assert build.returncode == 0, f"vite ssr 번들 실패:\n{build.stdout}\n{build.stderr}"
+        run = subprocess.run(
+            ["node", str(Path(outdir) / "spreadsheet_clip_used_entry.js")],
+            capture_output=True,
+            text=True,
+            encoding="utf-8",
+            errors="replace",
+            timeout=60,
+        )
+        assert run.stdout.strip(), run.stderr
+        result = json.loads(run.stdout)
+    assert result["fail"] == 0, result["failures"]
+    assert result["pass"] == 14