diff --git a/bin/df/df.c b/bin/df/df.c
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -530,8 +530,13 @@
 		    mwp->avail, fsbtoblk(sfsp->f_bavail,
 		    sfsp->f_bsize, blocksize));
 	}
+	/*
+	 * The percentage value shall be expressed as a positive integer,
+	 * with any fractional result causing it to be rounded to the next
+	 * highest integer.
+	 */
 	xo_emit(" {:used-percent/%5.0f}{U:%%}",
-	    availblks == 0 ? 100.0 : (double)used / (double)availblks * 100.0);
+	    availblks == 0 ? 100.0 : (double)((used * 100 + availblks - 1) / availblks));
 	if (iflag) {
 		inodes = sfsp->f_files;
 		used = inodes - sfsp->f_ffree;
@@ -551,7 +556,7 @@
 			xo_emit(" {:inodes-used-percent/    -}{U:} ");
 		else {
 			xo_emit(" {:inodes-used-percent/%4.0f}{U:%%} ",
-				(double)used / (double)inodes * 100.0);
+			    inodes == 0 ? 100.0 : (double)((used * 100 + inodes - 1) / inodes));
 		}
 	} else
 		xo_emit("  ");
diff --git a/bin/df/tests/t_df.sh b/bin/df/tests/t_df.sh
--- a/bin/df/tests/t_df.sh
+++ b/bin/df/tests/t_df.sh
@@ -19,50 +19,50 @@
 {
 	cat >expout <<EOF
 Filesystem    1K-blocks        Used       Avail Capacity  Mounted on
-filer:/      1202716672      135168  1202581504     0%    /filer
+filer:/      1202716672      135168  1202581504     1%    /filer
 filer:/      1202716672           0  1202716672     0%    /filer
-filer:/      1202716672   240543334   962173337    20%    /filer
-filer:/      1202716672   721630003   481086668    60%    /filer
-filer:/      1202716672  1142580838    60135833    95%    /filer
+filer:/      1202716672   240543334   962173337    21%    /filer
+filer:/      1202716672   721630003   481086668    61%    /filer
+filer:/      1202716672  1142580838    60135833    96%    /filer
 filer:/      1202716672  1202716672           0   100%    /filer
 filer:/      1202716672           0  1142580838     0%    /filer
-filer:/      1202716672   240543334   902037504    21%    /filer
-filer:/      1202716672   721630003   420950835    63%    /filer
+filer:/      1202716672   240543334   902037504    22%    /filer
+filer:/      1202716672   721630003   420950835    64%    /filer
 filer:/      1202716672  1142580838           0   100%    /filer
-filer:/      1202716672  1202716672   -60135833   105%    /filer
+filer:/      1202716672  1202716672   -60135833   106%    /filer
 filer:/      1202716672           0  1082445004     0%    /filer
-filer:/      1202716672   240543334   841901670    22%    /filer
+filer:/      1202716672   240543334   841901670    23%    /filer
 filer:/      1202716672   721630003   360815001    67%    /filer
 filer:/      1202716672  1142580838   -60135833   106%    /filer
-filer:/      1202716672  1202716672  -120271667   111%    /filer
+filer:/      1202716672  1202716672  -120271667   112%    /filer
 filer:/      1202716672           0  1022309171     0%    /filer
 filer:/      1202716672   240543334   781765836    24%    /filer
 filer:/      1202716672   721630003   300679168    71%    /filer
 filer:/      1202716672  1142580838  -120271667   112%    /filer
 filer:/      1202716672  1202716672  -180407500   118%    /filer
-/dev/ld0g    1308726116    17901268  1225388540     1%    /anon-root
+/dev/ld0g    1308726116    17901268  1225388540     2%    /anon-root
 /dev/ld0g    1308726116           0  1308726116     0%    /anon-root
-/dev/ld0g    1308726116   261745224  1046980892    20%    /anon-root
-/dev/ld0g    1308726116   785235672   523490444    60%    /anon-root
-/dev/ld0g    1308726116  1243289812    65436304    95%    /anon-root
+/dev/ld0g    1308726116   261745224  1046980892    21%    /anon-root
+/dev/ld0g    1308726116   785235672   523490444    61%    /anon-root
+/dev/ld0g    1308726116  1243289812    65436304    96%    /anon-root
 /dev/ld0g    1308726116  1308726116           0   100%    /anon-root
 /dev/ld0g    1308726116           0  1243289808     0%    /anon-root
-/dev/ld0g    1308726116   261745224   981544584    21%    /anon-root
-/dev/ld0g    1308726116   785235672   458054140    63%    /anon-root
+/dev/ld0g    1308726116   261745224   981544584    22%    /anon-root
+/dev/ld0g    1308726116   785235672   458054140    64%    /anon-root
 /dev/ld0g    1308726116  1243289812           0   100%    /anon-root
-/dev/ld0g    1308726116  1308726116   -65436304   105%    /anon-root
+/dev/ld0g    1308726116  1308726116   -65436304   106%    /anon-root
 /dev/ld0g    1308726116           0  1177853504     0%    /anon-root
-/dev/ld0g    1308726116   261745224   916108280    22%    /anon-root
+/dev/ld0g    1308726116   261745224   916108280    23%    /anon-root
 /dev/ld0g    1308726116   785235672   392617832    67%    /anon-root
 /dev/ld0g    1308726116  1243289812   -65436304   106%    /anon-root
-/dev/ld0g    1308726116  1308726116  -130872608   111%    /anon-root
+/dev/ld0g    1308726116  1308726116  -130872608   112%    /anon-root
 /dev/ld0g    1308726116           0  1112417196     0%    /anon-root
 /dev/ld0g    1308726116   261745224   850671972    24%    /anon-root
 /dev/ld0g    1308726116   785235672   327181528    71%    /anon-root
 /dev/ld0g    1308726116  1243289812  -130872608   112%    /anon-root
 /dev/ld0g    1308726116  1308726116  -196308916   118%    /anon-root
-/dev/strpct 21474836476 10737418240 10737418236    50%    /strpct
-/dev/wd0e      10485688     2859932     7625756    27%    /mount/windows/C
+/dev/strpct 21474836476 10737418240 10737418236    51%    /strpct
+/dev/wd0e      10485688     2859932     7625756    28%    /mount/windows/C
 EOF
 	atf_check -s exit:0 -o file:expout -e empty \
 	    -x "BLOCKSIZE=1k $(atf_get_srcdir)/h_df -n"
@@ -79,50 +79,50 @@
 {
 	cat >expout <<EOF
 Filesystem     Size    Used   Avail Capacity  Mounted on
-filer:/        1.1T    132M    1.1T     0%    /filer
+filer:/        1.1T    132M    1.1T     1%    /filer
 filer:/        1.1T      0B    1.1T     0%    /filer
-filer:/        1.1T    229G    918G    20%    /filer
-filer:/        1.1T    688G    459G    60%    /filer
-filer:/        1.1T    1.1T     57G    95%    /filer
+filer:/        1.1T    229G    918G    21%    /filer
+filer:/        1.1T    688G    459G    61%    /filer
+filer:/        1.1T    1.1T     57G    96%    /filer
 filer:/        1.1T    1.1T      0B   100%    /filer
 filer:/        1.1T      0B    1.1T     0%    /filer
-filer:/        1.1T    229G    860G    21%    /filer
-filer:/        1.1T    688G    401G    63%    /filer
+filer:/        1.1T    229G    860G    22%    /filer
+filer:/        1.1T    688G    401G    64%    /filer
 filer:/        1.1T    1.1T      0B   100%    /filer
-filer:/        1.1T    1.1T    -57G   105%    /filer
+filer:/        1.1T    1.1T    -57G   106%    /filer
 filer:/        1.1T      0B    1.0T     0%    /filer
-filer:/        1.1T    229G    803G    22%    /filer
+filer:/        1.1T    229G    803G    23%    /filer
 filer:/        1.1T    688G    344G    67%    /filer
 filer:/        1.1T    1.1T    -57G   106%    /filer
-filer:/        1.1T    1.1T   -115G   111%    /filer
+filer:/        1.1T    1.1T   -115G   112%    /filer
 filer:/        1.1T      0B    975G     0%    /filer
 filer:/        1.1T    229G    746G    24%    /filer
 filer:/        1.1T    688G    287G    71%    /filer
 filer:/        1.1T    1.1T   -115G   112%    /filer
 filer:/        1.1T    1.1T   -172G   118%    /filer
-/dev/ld0g      1.2T     17G    1.1T     1%    /anon-root
+/dev/ld0g      1.2T     17G    1.1T     2%    /anon-root
 /dev/ld0g      1.2T      0B    1.2T     0%    /anon-root
-/dev/ld0g      1.2T    250G    998G    20%    /anon-root
-/dev/ld0g      1.2T    749G    499G    60%    /anon-root
-/dev/ld0g      1.2T    1.2T     62G    95%    /anon-root
+/dev/ld0g      1.2T    250G    998G    21%    /anon-root
+/dev/ld0g      1.2T    749G    499G    61%    /anon-root
+/dev/ld0g      1.2T    1.2T     62G    96%    /anon-root
 /dev/ld0g      1.2T    1.2T      0B   100%    /anon-root
 /dev/ld0g      1.2T      0B    1.2T     0%    /anon-root
-/dev/ld0g      1.2T    250G    936G    21%    /anon-root
-/dev/ld0g      1.2T    749G    437G    63%    /anon-root
+/dev/ld0g      1.2T    250G    936G    22%    /anon-root
+/dev/ld0g      1.2T    749G    437G    64%    /anon-root
 /dev/ld0g      1.2T    1.2T      0B   100%    /anon-root
-/dev/ld0g      1.2T    1.2T    -62G   105%    /anon-root
+/dev/ld0g      1.2T    1.2T    -62G   106%    /anon-root
 /dev/ld0g      1.2T      0B    1.1T     0%    /anon-root
-/dev/ld0g      1.2T    250G    874G    22%    /anon-root
+/dev/ld0g      1.2T    250G    874G    23%    /anon-root
 /dev/ld0g      1.2T    749G    374G    67%    /anon-root
 /dev/ld0g      1.2T    1.2T    -62G   106%    /anon-root
-/dev/ld0g      1.2T    1.2T   -125G   111%    /anon-root
+/dev/ld0g      1.2T    1.2T   -125G   112%    /anon-root
 /dev/ld0g      1.2T      0B    1.0T     0%    /anon-root
 /dev/ld0g      1.2T    250G    811G    24%    /anon-root
 /dev/ld0g      1.2T    749G    312G    71%    /anon-root
 /dev/ld0g      1.2T    1.2T   -125G   112%    /anon-root
 /dev/ld0g      1.2T    1.2T   -187G   118%    /anon-root
-/dev/strpct     20T     10T     10T    50%    /strpct
-/dev/wd0e       10G    2.7G    7.3G    27%    /mount/windows/C
+/dev/strpct     20T     10T     10T    51%    /strpct
+/dev/wd0e       10G    2.7G    7.3G    28%    /mount/windows/C
 EOF
 	atf_check -s exit:0 -o file:expout -e empty \
 	    -x "BLOCKSIZE=1k $(atf_get_srcdir)/h_df -hn"