diff --git a/apps/speedalt/README.md b/apps/speedalt/README.md
index cc8b126e1..5e9d707ba 100644
--- a/apps/speedalt/README.md
+++ b/apps/speedalt/README.md
@@ -1 +1,5 @@
-to do
+Displays the GPS speed and altitude. One is displyed on the watch face using the largest possible characters depending on the number of digits. The other is in a smaller display below that.
+
+Display Tap : Swaps the displays. You can have either speed or altitude on the large display.
+
+BTN3 : Select the desire display units. Speed can be as per the default locale, kph, knots, mph or m/s. Altitude can be feet or metres.