diff --git a/dive.c b/dive.c
index 2ecb56d06..d1f4f8bd2 100644
--- a/dive.c
+++ b/dive.c
@@ -2860,6 +2860,53 @@ void set_userid(char *rUserId)
 		prefs.userid[30]='\0';
 }
 
+/* this sets a usually unused copy of the preferences with the units
+ * that were active the last time the dive list was saved to git storage
+ * (this isn't used in XML files); storing the unit preferences in the
+ * data file is usually pointless (that's a setting of the software,
+ * not a property of the data), but it's a great hint of what the user
+ * might expect to see when creating a backend service that visualizes
+ * the dive list without Subsurface running - so this is basically a
+ * functionality for the core library that Subsurface itself doesn't
+ * use but that another consumer of the library (like an HTML exporter)
+ * will need */
+void set_informational_units(char *units)
+{
+	if (strstr(units, "METRIC")) {
+		informational_prefs.unit_system = METRIC;
+	} else if (strstr(units, "IMPERIAL")) {
+		informational_prefs.unit_system = IMPERIAL;
+	} else if (strstr(units, "PERSONALIZE")) {
+		informational_prefs.unit_system = PERSONALIZE;
+		if (strstr(units, "METERS"))
+			informational_prefs.units.length = METERS;
+		if (strstr(units, "FEET"))
+			informational_prefs.units.length = FEET;
+		if (strstr(units, "LITER"))
+			informational_prefs.units.volume = LITER;
+		if (strstr(units, "CUFT"))
+			informational_prefs.units.volume = CUFT;
+		if (strstr(units, "BAR"))
+			informational_prefs.units.pressure = BAR;
+		if (strstr(units, "PSI"))
+			informational_prefs.units.pressure = PSI;
+		if (strstr(units, "PASCAL"))
+			informational_prefs.units.pressure = PASCAL;
+		if (strstr(units, "CELSIUS"))
+			informational_prefs.units.temperature = CELSIUS;
+		if (strstr(units, "FAHRENHEIT"))
+			informational_prefs.units.temperature = FAHRENHEIT;
+		if (strstr(units, "KG"))
+			informational_prefs.units.weight = KG;
+		if (strstr(units, "LBS"))
+			informational_prefs.units.weight = LBS;
+		if (strstr(units, "SECONDS"))
+			informational_prefs.units.vertical_speed_time = SECONDS;
+		if (strstr(units, "MINUTES"))
+			informational_prefs.units.vertical_speed_time = MINUTES;
+	}
+}
+
 void average_max_depth(struct diveplan *dive, int *avg_depth, int *max_depth)
 {
 	int integral = 0;
diff --git a/dive.h b/dive.h
index 6d142fd3e..36d9a1200 100644
--- a/dive.h
+++ b/dive.h
@@ -858,6 +858,7 @@ extern double strtod_flags(const char *str, const char **ptr, unsigned int flags
 
 extern void set_save_userid_local(short value);
 extern void set_userid(char *user_id);
+extern void set_informational_units(char *units);
 
 extern const char *get_dive_date_c_string(timestamp_t when);
 extern void update_setpoint_events(struct divecomputer *dc);
diff --git a/load-git.c b/load-git.c
index 59bb8adc6..08eef085d 100644
--- a/load-git.c
+++ b/load-git.c
@@ -727,6 +727,12 @@ static void parse_trip_notes(char *line, struct membuffer *str, void *_trip)
 static void parse_settings_autogroup(char *line, struct membuffer *str, void *_unused)
 { set_autogroup(1); }
 
+static void parse_settings_units(char *line, struct membuffer *str, void *unused)
+{
+	if (line)
+		set_informational_units(line);
+}
+
 static void parse_settings_userid(char *line, struct membuffer *str, void *_unused)
 {
 	if (line) {
@@ -895,7 +901,7 @@ static void trip_parser(char *line, struct membuffer *str, void *_trip)
 static struct keyword_action settings_action[] = {
 #undef D
 #define D(x) { #x, parse_settings_ ## x }
-	D(autogroup), D(divecomputerid), D(subsurface), D(userid), D(version),
+	D(autogroup), D(divecomputerid), D(subsurface), D(units), D(userid), D(version),
 };
 
 static void settings_parser(char *line, struct membuffer *str, void *_unused)
diff --git a/pref.h b/pref.h
index 3c39409a7..c657cf289 100644
--- a/pref.h
+++ b/pref.h
@@ -120,7 +120,7 @@ enum cloud_status {
 	CS_VERIFIED
 };
 
-extern struct preferences prefs, default_prefs;
+extern struct preferences prefs, default_prefs, informational_prefs;
 
 #define PP_GRAPHS_ENABLED (prefs.pp_graphs.po2 || prefs.pp_graphs.pn2 || prefs.pp_graphs.phe)
 
diff --git a/save-git.c b/save-git.c
index f76029f11..3f540eab9 100644
--- a/save-git.c
+++ b/save-git.c
@@ -786,6 +786,23 @@ static int save_one_trip(git_repository *repo, struct dir *tree, dive_trip_t *tr
 	return 0;
 }
 
+static void save_units(void *_b)
+{
+	struct membuffer *b =_b;
+	if (prefs.unit_system == METRIC)
+		put_string(b, "units METRIC\n");
+	else if (prefs.unit_system == IMPERIAL)
+		put_string(b, "units IMPERIAL\n");
+	else
+		put_format(b, "units PERSONALIZE %s %s %s %s %s %s",
+			   prefs.units.length == METERS ? "METERS" : "FEET",
+			   prefs.units.volume == LITER ? "LITER" : "CUFT",
+			   prefs.units.pressure == BAR ? "BAR" : prefs.units.pressure == PSI ? "PSI" : "PASCAL",
+			   prefs.units.temperature == CELSIUS ? "CELSIUS" : prefs.units.temperature == FAHRENHEIT ? "FAHRENHEIT" : "KELVIN",
+			   prefs.units.weight == KG ? "KG" : "LBS",
+			   prefs.units.vertical_speed_time == SECONDS ? "SECONDS" : "MINUTES");
+}
+
 static void save_userid(void *_b)
 {
 	struct membuffer *b = _b;
@@ -824,6 +841,7 @@ static void save_settings(git_repository *repo, struct dir *tree)
 	save_userid(&b);
 	call_for_each_dc(&b, save_one_device, false);
 	cond_put_format(autogroup, &b, "autogroup\n");
+	save_units(&b);
 
 	blob_insert(repo, tree, &b, "00-Subsurface");
 }
diff --git a/subsurfacestartup.c b/subsurfacestartup.c
index ab4af7035..a64c8175d 100644
--- a/subsurfacestartup.c
+++ b/subsurfacestartup.c
@@ -3,7 +3,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include "gettext.h"
-struct preferences prefs;
+struct preferences prefs, informational_prefs;
 struct preferences default_prefs = {
 	.cloud_base_url = "https://cloud.subsurface-divelog.org/",
 	.units = SI_UNITS,