diff --git a/src/include/options.h b/src/include/options.h
index 8cbe183..6d5e696 100644
--- a/src/include/options.h
+++ b/src/include/options.h
@@ -34,6 +34,7 @@ struct opts_s {           /* structure describing run-time options */
 	bool average_rate;             /* average rate counter flag */
 	bool bytes;                    /* bytes transferred flag */
 	bool bits;                     /* report transfer size in bits */
+	bool si;                       /* decimal prefix flag */
 	bool bufpercent;               /* transfer buffer percentage flag */
 	size_t lastwritten;            /* show N bytes last written */
 	bool force;                    /* force-if-not-terminal flag */
diff --git a/src/include/pv-internal.h b/src/include/pv-internal.h
index 29ebef5..21f67d4 100644
--- a/src/include/pv-internal.h
+++ b/src/include/pv-internal.h
@@ -105,6 +105,7 @@ struct pvstate_s {
 		bool wait;                       /* wait for data before display */
 		bool linemode;                   /* count lines instead of bytes */
 		bool bits;			 /* report bits instead of bytes */
+		bool si;			 /* use decimal prefixes */
 		bool null_terminated_lines;      /* lines are null-terminated */
 		bool no_display;                 /* do nothing other than pipe data */
 		unsigned int skip_errors;        /* skip read errors counter */
diff --git a/src/include/pv.h b/src/include/pv.h
index a2c9132..7ef5234 100644
--- a/src/include/pv.h
+++ b/src/include/pv.h
@@ -164,6 +164,7 @@ extern void pv_state_wait_set(pvstate_t, bool);
 extern void pv_state_delay_start_set(pvstate_t, double);
 extern void pv_state_linemode_set(pvstate_t, bool);
 extern void pv_state_bits_set(pvstate_t, bool);
+extern void pv_state_si_set(pvstate_t, bool);
 extern void pv_state_null_terminated_lines_set(pvstate_t, bool);
 extern void pv_state_no_display_set(pvstate_t, bool);
 extern void pv_state_skip_errors_set(pvstate_t, unsigned int);
diff --git a/src/main/help.c b/src/main/help.c
index bd2ce22..fcad22e 100644
--- a/src/main/help.c
+++ b/src/main/help.c
@@ -307,6 +307,9 @@ void display_help(void)
 		{ "-8", "--bits", NULL,
 		 N_("show number of bits transferred"),
 		 { 0, 0, 0, 0} },
+		{ "-k", "--si", NULL,
+		 N_("show sizes in powers of 1000 (e.g., 1.1G)"),
+		 { 0, 0, 0, 0} },
 		{ "-T", "--buffer-percent", NULL,
 		 N_("show percentage of transfer buffer in use"),
 		 { 0, 0, 0, 0} },
diff --git a/src/main/main.c b/src/main/main.c
index 653df68..de5fadf 100644
--- a/src/main/main.c
+++ b/src/main/main.c
@@ -278,6 +278,7 @@ int main(int argc, char **argv)
 	pv_state_delay_start_set(state, opts->delay_start);
 	pv_state_linemode_set(state, opts->linemode);
 	pv_state_bits_set(state, opts->bits);
+	pv_state_si_set(state, opts->si);
 	pv_state_null_terminated_lines_set(state, opts->null_terminated_lines);
 	pv_state_skip_errors_set(state, opts->skip_errors);
 	pv_state_error_skip_block_set(state, opts->error_skip_block);
diff --git a/src/main/options.c b/src/main/options.c
index 01df7a1..482d511 100644
--- a/src/main/options.c
+++ b/src/main/options.c
@@ -114,6 +114,7 @@ opts_t opts_parse(unsigned int argc, char **argv)
 		{ "average-rate", 0, NULL, (int) 'a' },
 		{ "bytes", 0, NULL, (int) 'b' },
 		{ "bits", 0, NULL, (int) '8' },
+		{ "si", 0, NULL, (int) 'k' },
 		{ "buffer-percent", 0, NULL, (int) 'T' },
 		{ "last-written", 1, NULL, (int) 'A' },
 		{ "force", 0, NULL, (int) 'f' },
@@ -151,7 +152,7 @@ opts_t opts_parse(unsigned int argc, char **argv)
 	/*@+nullassign@ */
 	int option_index = 0;
 #endif				/* HAVE_GETOPT_LONG */
-	char *short_options = "hVpteIrab8TA:fnqcWD:s:l0i:w:H:N:F:L:B:CEZ:SYKXR:P:d:m:"
+	char *short_options = "hVpteIrab8kTA:fnqcWD:s:l0i:w:H:N:F:L:B:CEZ:SYKXR:P:d:m:"
 #ifdef ENABLE_DEBUGGING
 	    "!:"
 #endif
@@ -335,6 +336,9 @@ opts_t opts_parse(unsigned int argc, char **argv)
 			opts->bits = true;
 			numopts++;
 			break;
+		case 'k':
+			opts->si = true;
+			break;
 		case 'T':
 			opts->bufpercent = true;
 			numopts++;
diff --git a/src/pv/display.c b/src/pv/display.c
index dccda09..c65e3c4 100644
--- a/src/pv/display.c
+++ b/src/pv/display.c
@@ -146,10 +146,11 @@ static long pv__seconds_remaining(const off_t so_far, const off_t total, const l
 }
 
 /*
- * Types of transfer count - bytes or lines.
+ * Types of transfer count - bytes, decimal bytes or lines.
  */
 typedef enum {
 	PV_TRANSFERCOUNT_BYTES,
+	PV_TRANSFERCOUNT_DECBYTES,
 	PV_TRANSFERCOUNT_LINES
 } pv__transfercount_t;
 
@@ -346,6 +347,9 @@ static void pv__sizestr(char *buffer, size_t bufsize, char *format,
 	if (count_type == PV_TRANSFERCOUNT_BYTES) {
 		suffix = suffix_bytes;
 		divider = 1024.0;
+	} else if (count_type == PV_TRANSFERCOUNT_DECBYTES) {
+		suffix = suffix_bytes;
+		divider = 1000.0;
 	} else {
 		suffix = suffix_basic;
 		divider = 1000.0;
@@ -808,6 +812,7 @@ static bool pv__format(pvstate_t state, long double elapsed_sec, off_t bytes_sin
 		time_t then;
 		struct tm *time_ptr;
 		char *time_format;
+		pv__transfercount_t count_type;
 
 		if (!state->display.component[component_type].required)
 			continue;
@@ -828,6 +833,12 @@ static bool pv__format(pvstate_t state, long double elapsed_sec, off_t bytes_sin
 		component_content[0] = '\0';
 		component_buf_size = PV_SIZEOF_COMPONENT_STR;
 
+		count_type = PV_TRANSFERCOUNT_BYTES;
+		if (state->control.linemode)
+			count_type = PV_TRANSFERCOUNT_LINES;
+		else if (state->control.si)
+			count_type = PV_TRANSFERCOUNT_DECBYTES;
+
 		switch (component_type) {
 
 		case PV_COMPONENT_STRING:
@@ -842,11 +853,10 @@ static bool pv__format(pvstate_t state, long double elapsed_sec, off_t bytes_sin
 			/*@-mustfreefresh @ */
 			if (state->control.bits && !state->control.linemode) {
 				pv__sizestr(component_content, component_buf_size, "%s",
-					    (long double) total_bytes * 8, "", _("b"), PV_TRANSFERCOUNT_BYTES);
+					    (long double) total_bytes * 8, "", _("b"), count_type);
 			} else {
 				pv__sizestr(component_content, component_buf_size, "%s",
-					    (long double) total_bytes, "", _("B"),
-					    state->control.linemode ? PV_TRANSFERCOUNT_LINES : PV_TRANSFERCOUNT_BYTES);
+					    (long double) total_bytes, "", _("B"), count_type);
 			}
 			/*@+mustfreefresh @ */
 			/* splint: we trust gettext() not to really leak memory. */
@@ -888,12 +898,11 @@ static bool pv__format(pvstate_t state, long double elapsed_sec, off_t bytes_sin
 			if (state->control.bits && !state->control.linemode) {
 				/* bits per second */
 				pv__sizestr(component_content, component_buf_size, "[%s]", 8 * rate, "", _("b/s"),
-					    PV_TRANSFERCOUNT_BYTES);
+					    count_type);
 			} else {
 				/* bytes or lines per second */
 				pv__sizestr(component_content, component_buf_size,
-					    "[%s]", rate, _("/s"), _("B/s"),
-					    state->control.linemode ? PV_TRANSFERCOUNT_LINES : PV_TRANSFERCOUNT_BYTES);
+					    "[%s]", rate, _("/s"), _("B/s"), count_type);
 			}
 			/*@+mustfreefresh @ *//* splint: see above. */
 			break;
@@ -904,13 +913,12 @@ static bool pv__format(pvstate_t state, long double elapsed_sec, off_t bytes_sin
 			if (state->control.bits && !state->control.linemode) {
 				/* bits per second */
 				pv__sizestr(component_content, component_buf_size,
-					    "[%s]", 8 * average_rate, "", _("b/s"), PV_TRANSFERCOUNT_BYTES);
+					    "[%s]", 8 * average_rate, "", _("b/s"), count_type);
 			} else {
 				/* bytes or lines per second */
 				pv__sizestr(component_content,
 					    component_buf_size,
-					    "[%s]", average_rate, _("/s"), _("B/s"),
-					    state->control.linemode ? PV_TRANSFERCOUNT_LINES : PV_TRANSFERCOUNT_BYTES);
+					    "[%s]", average_rate, _("/s"), _("B/s"), count_type);
 			}
 			/*@+mustfreefresh @ *//* splint: see above. */
 			break;
diff --git a/src/pv/state.c b/src/pv/state.c
index 428ceac..0e60eac 100644
--- a/src/pv/state.c
+++ b/src/pv/state.c
@@ -234,6 +234,11 @@ void pv_state_bits_set(pvstate_t state, bool bits)
 	state->control.bits = bits;
 }
 
+void pv_state_si_set(pvstate_t state, bool si)
+{
+	state->control.si = si;
+}
+
 void pv_state_null_terminated_lines_set(pvstate_t state, bool val)
 {
 	state->control.null_terminated_lines = val;