diff --git a/src/cut.c b/src/cut.c
index 3c0a8533..35c38841 100644
--- a/src/cut.c
+++ b/src/cut.c
@@ -34,7 +34,7 @@ void do_deletion(undo_type action)
 		int charlen = char_length(openfile->current->data + openfile->current_x);
 		size_t line_len = strlen(openfile->current->data + openfile->current_x);
 #ifndef NANO_TINY
-		size_t old_amount = 0;
+		size_t old_amount = openfile->current->extrarows;
 
 		/* If the type of action changed or the cursor moved to a different
 		 * line, create a new undo item, otherwise update the existing item. */
@@ -43,20 +43,18 @@ void do_deletion(undo_type action)
 			add_undo(action, NULL);
 		else
 			update_undo(action);
-
-		if (ISSET(SOFTWRAP))
-			old_amount = extra_chunks_in(openfile->current);
 #endif
 		/* Move the remainder of the line "in", over the current character. */
 		memmove(&openfile->current->data[openfile->current_x],
 					&openfile->current->data[openfile->current_x + charlen],
 					line_len - charlen + 1);
 #ifndef NANO_TINY
-		/* When softwrapping and the number of chunks in the current line has
-		 * changed, the chunks must be renumbered and the screen refreshed. */
-		if (ISSET(SOFTWRAP) && extra_chunks_in(openfile->current) != old_amount) {
-			renumber_from(openfile->current);
-			refresh_needed = TRUE;
+		/* When softwrapping, recompute the number of chunks in the line,
+		 * and schedule a refresh if the number changed. */
+		if (ISSET(SOFTWRAP)) {
+			openfile->current->extrarows = extra_chunks_in(openfile->current);
+			if (openfile->current->extrarows != old_amount)
+				refresh_needed = TRUE;
 		}
 
 		/* Adjust the mark if it is after the cursor on the current line. */
diff --git a/src/files.c b/src/files.c
index b1674e95..e21761fe 100644
--- a/src/files.c
+++ b/src/files.c
@@ -356,6 +356,16 @@ bool has_valid_path(const char *filename)
 	return validity;
 }
 
+/* Compute and store how many extra rows each line needs when softwrapping. */
+void compute_the_extra_rows_per_line(void)
+{
+#ifndef NANO_TINY
+	if (ISSET(SOFTWRAP))
+		for (linestruct *ln = openfile->filetop; ln != NULL; ln = ln->next)
+			ln->extrarows = extra_chunks_in(ln);
+#endif
+}
+
 /* This does one of three things.  If the filename is "", it just creates
  * a new empty buffer.  When the filename is not empty, it reads that file
  * into a new buffer when requested, otherwise into the existing buffer. */
@@ -453,6 +463,8 @@ bool open_buffer(const char *filename, bool new_one)
 		openfile->placewewant = 0;
 	}
 
+	compute_the_extra_rows_per_line();
+
 #ifdef ENABLE_COLOR
 	/* If a new buffer was opened, check whether a syntax can be applied. */
 	if (new_one)
@@ -527,6 +539,8 @@ void redecorate_after_switch(void)
 	 * or softwrap mode may have been toggled, so make sure that the
 	 * starting column for the first row gets an appropriate value. */
 	ensure_firstcolumn_is_aligned();
+
+	compute_the_extra_rows_per_line();
 #endif
 
 	/* Update title bar and multiline info to match the current buffer. */
diff --git a/src/nano.c b/src/nano.c
index b3296113..0f961b7f 100644
--- a/src/nano.c
+++ b/src/nano.c
@@ -76,9 +76,7 @@ linestruct *make_new_node(linestruct *prevnode)
 #endif
 	newnode->lineno = (prevnode) ? prevnode->lineno + 1 : 1;
 #ifndef NANO_TINY
-	if (ISSET(SOFTWRAP))
-		newnode->chunk_nr = (prevnode) ?
-						prevnode->chunk_nr + extra_chunks_in(prevnode) + 1 : 1;
+	newnode->extrarows = -2;  /* Bad value, to make it easier to find bugs. */
 	newnode->has_anchor = FALSE;
 #endif
 
@@ -154,7 +152,7 @@ linestruct *copy_node(const linestruct *src)
 #endif
 	dst->lineno = src->lineno;
 #ifndef NANO_TINY
-	dst->chunk_nr = src->chunk_nr;
+	dst->extrarows = src->extrarows;
 	dst->has_anchor = FALSE;
 #endif
 
@@ -190,21 +188,8 @@ void renumber_from(linestruct *line)
 {
 	ssize_t number = (line->prev == NULL) ? 0 : line->prev->lineno;
 
-#ifndef NANO_TINY
-	if (ISSET(SOFTWRAP) && line->prev == NULL) {
-		line->lineno = ++number;
-		line->chunk_nr = 1;
-		line = line->next;
-	}
-#endif
-
 	while (line != NULL) {
 		line->lineno = ++number;
-#ifndef NANO_TINY
-		if (ISSET(SOFTWRAP))
-			line->chunk_nr = line->prev->chunk_nr +
-									extra_chunks_in(line->prev) + 1;
-#endif
 		line = line->next;
 	}
 }
@@ -1095,7 +1080,7 @@ void do_toggle(int flag)
 			break;
 		case SOFTWRAP:
 			if (ISSET(SOFTWRAP))
-				renumber_from(openfile->filetop);
+				compute_the_extra_rows_per_line();
 			else
 				openfile->firstcolumn = 0;
 			refresh_needed = TRUE;
@@ -1426,12 +1411,12 @@ void inject(char *burst, size_t count)
 	linestruct *thisline = openfile->current;
 	size_t datalen = strlen(thisline->data);
 #ifndef NANO_TINY
-	size_t original_row = 0, old_amount = 0;
+	size_t old_amount = openfile->current->extrarows;
+	size_t original_row = 0;
 
 	if (ISSET(SOFTWRAP)) {
 		if (openfile->current_y == editwinrows - 1)
 			original_row = chunk_for(xplustabs(), thisline);
-		old_amount = extra_chunks_in(thisline);
 	}
 #endif
 
@@ -1492,15 +1477,17 @@ void inject(char *burst, size_t count)
 #endif
 
 #ifndef NANO_TINY
-	/* If we were on the last row of the edit window and moved to a new chunk,
-	 * or if the number of chunks that the current softwrapped line occupies
-	 * changed, we need a full refresh. */
-	if (ISSET(SOFTWRAP) && ((openfile->current_y == editwinrows - 1 &&
-				chunk_for(xplustabs(), openfile->current) > original_row) ||
-				extra_chunks_in(openfile->current) != old_amount)) {
-		renumber_from(openfile->current);
-		refresh_needed = TRUE;
-		focusing = FALSE;
+	/* When softwrapping and the number of chunks in the current line changed,
+	 * or we were on the last row of the edit window and moved to a new chunk,
+	 * we need a full refresh. */
+	if (ISSET(SOFTWRAP)) {
+		openfile->current->extrarows = extra_chunks_in(openfile->current);
+		if (openfile->current->extrarows != old_amount ||
+					(openfile->current_y == editwinrows - 1 &&
+					chunk_for(xplustabs(), openfile->current) > original_row)) {
+			refresh_needed = TRUE;
+			focusing = FALSE;
+		}
 	}
 #endif
 
diff --git a/src/nano.h b/src/nano.h
index b14296e1..7df938ff 100644
--- a/src/nano.h
+++ b/src/nano.h
@@ -285,8 +285,8 @@ typedef struct linestruct {
 	ssize_t lineno;
 		/* The number of this line. */
 #ifndef NANO_TINY
-	ssize_t chunk_nr;
-		/* The ordinal number of the first chunk in this line. */
+	ssize_t extrarows;
+		/* The extra rows that this line occupies when softwrapping. */
 #endif
 	struct linestruct *next;
 		/* Next node. */
diff --git a/src/proto.h b/src/proto.h
index fc0e3272..d59be1b8 100644
--- a/src/proto.h
+++ b/src/proto.h
@@ -283,6 +283,7 @@ void make_new_buffer(void);
 #ifndef NANO_TINY
 bool delete_lockfile(const char *lockfilename);
 #endif
+void compute_the_extra_rows_per_line(void);
 bool open_buffer(const char *filename, bool new_buffer);
 void set_modified(void);
 void prepare_for_display(void);
diff --git a/src/search.c b/src/search.c
index 0570a482..6ffa9693 100644
--- a/src/search.c
+++ b/src/search.c
@@ -654,6 +654,10 @@ ssize_t do_replace_loop(const char *needle, bool whole_word_only,
 			free(openfile->current->data);
 			openfile->current->data = copy;
 
+#ifndef NANO_TINY
+			if (ISSET(SOFTWRAP))
+				openfile->current->extrarows = extra_chunks_in(openfile->current);
+#endif
 #ifdef ENABLE_COLOR
 			/* Check whether the replacement requires a change in the coloring. */
 			check_the_multis(openfile->current);
diff --git a/src/text.c b/src/text.c
index adab2631..6f5feae8 100644
--- a/src/text.c
+++ b/src/text.c
@@ -102,6 +102,9 @@ void indent_a_line(linestruct *line, char *indentation)
 
 	openfile->totsize += indent_len;
 
+	if (ISSET(SOFTWRAP))
+		line->extrarows = extra_chunks_in(line);
+
 	/* Compensate for the change in the current line. */
 	if (line == openfile->mark && openfile->mark_x > 0)
 		openfile->mark_x += indent_len;
@@ -230,6 +233,9 @@ void unindent_a_line(linestruct *line, size_t indent_len)
 
 	openfile->totsize -= indent_len;
 
+	if (ISSET(SOFTWRAP))
+		line->extrarows = extra_chunks_in(line);
+
 	/* Adjust the positions of mark and cursor, when they are affected. */
 	compensate_leftward(line, indent_len);
 }
@@ -418,8 +424,13 @@ void do_comment(void)
 	/* Comment/uncomment each of the selected lines when possible, and
 	 * store undo data when a line changed. */
 	for (line = top; line != bot->next; line = line->next) {
-		if (comment_line(action, line, comment_seq))
+		if (comment_line(action, line, comment_seq)) {
+#ifndef NANO_TINY
+			if (ISSET(SOFTWRAP))
+				line->extrarows = extra_chunks_in(line);
+#endif
 			update_multiline_undo(line->lineno, "");
+		}
 	}
 
 	set_modified();
@@ -660,6 +671,9 @@ void do_undo(void)
 	openfile->mark = NULL;
 	openfile->placewewant = xplustabs();
 
+	if (ISSET(SOFTWRAP))
+		openfile->current->extrarows = extra_chunks_in(openfile->current);
+
 	openfile->totsize = u->wassize;
 
 	/* When at the point where the file was last saved, unset "Modified". */
@@ -818,6 +832,9 @@ void do_redo(void)
 	openfile->mark = NULL;
 	openfile->placewewant = xplustabs();
 
+	if (ISSET(SOFTWRAP))
+		openfile->current->extrarows = extra_chunks_in(openfile->current);
+
 	openfile->totsize = u->newsize;
 
 	/* When at the point where the file was last saved, unset "Modified". */
diff --git a/src/winio.c b/src/winio.c
index af25a144..376ae5a1 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -2957,10 +2957,12 @@ void draw_scrollbar(void)
 	int first_row = openfile->edittop->lineno;
 
 	if (ISSET(SOFTWRAP)) {
-		totalrows = openfile->filebot->chunk_nr +
-							extra_chunks_in(openfile->filebot);
-		first_row = openfile->edittop->chunk_nr +
-							chunk_for(openfile->firstcolumn, openfile->edittop);
+		for (linestruct *ln = openfile->filetop; ln != openfile->edittop; ln = ln->next)
+			first_row += ln->extrarows;
+		first_row += chunk_for(openfile->firstcolumn, openfile->edittop);
+
+		for (linestruct *ln = openfile->filetop; ln != NULL; ln = ln->next)
+			totalrows += ln->extrarows;
 	}
 
 	int lowest = ((first_row - 1) * editwinrows) / totalrows;
@@ -3142,11 +3144,10 @@ size_t leftedge_for(size_t column, linestruct *line)
  * has changed, because then the width of softwrapped chunks has changed. */
 void ensure_firstcolumn_is_aligned(void)
 {
-	if (ISSET(SOFTWRAP)) {
+	if (ISSET(SOFTWRAP))
 		openfile->firstcolumn = leftedge_for(openfile->firstcolumn,
 														openfile->edittop);
-		renumber_from(openfile->filetop);
-	} else
+	else
 		openfile->firstcolumn = 0;
 
 	/* If smooth scrolling is on, make sure the viewport doesn't center. */