diff --git a/html/formatter.js b/html/formatter.js
index e3fa51c..8ab765a 100644
--- a/html/formatter.js
+++ b/html/formatter.js
@@ -163,7 +163,7 @@ function format_onground (alt) {
 // alt in feet
 function convert_altitude(alt, displayUnits) {
 	if (displayUnits === "metric") {
-		return alt * 0.3048;  // feet to metres
+		return alt * 0.3048;  // feet to meters
 	}
 
 	return alt;
@@ -195,7 +195,7 @@ function format_speed_long(speed, displayUnits) {
 // speed in knots
 function convert_speed(speed, displayUnits) {
 	if (displayUnits === "metric") {
-		return speed * 1.852;  // knots to kilometres per hour
+		return speed * 1.852;  // knots to kilometers per hour
 	}
 	else if (displayUnits === "imperial") {
 		return speed * 1.151;  // knots to miles per hour
@@ -204,7 +204,7 @@ function convert_speed(speed, displayUnits) {
 	return speed;
 }
 
-// dist in metres
+// dist in meters
 function format_distance_brief(dist, displayUnits) {
 	if (dist == null) {
 		return "";
@@ -213,7 +213,7 @@ function format_distance_brief(dist, displayUnits) {
 	return convert_distance(dist, displayUnits).toFixed(1);
 }
 
-// dist in metres
+// dist in meters
 function format_distance_long(dist, displayUnits, fixed) {
 	if (dist == null) {
 		return "n/a";
@@ -238,24 +238,24 @@ function format_distance_short (dist, displayUnits) {
 	return dist_text;
 }
 
-// dist in metres
+// dist in meters
 function convert_distance(dist, displayUnits) {
 	if (displayUnits === "metric") {
-		return (dist / 1000); // metres to kilometres
+		return (dist / 1000); // meters to kilometres
 	}
 	else if (displayUnits === "imperial") {
-		return (dist / 1609); // metres to miles
+		return (dist / 1609); // meters to miles
 	}
-	return (dist / 1852); // metres to nautical miles
+	return (dist / 1852); // meters to nautical miles
 }
 
-// dist in metres
-// converts metres to feet or just returns metres
+// dist in meters
+// converts meters to feet or just returns metres
 function convert_distance_short(dist, displayUnits) {
 	if (displayUnits === "imperial") {
-		return (dist / 0.3048); // metres to feet
+		return (dist / 0.3048); // meters to feet
 	}
-	return dist; // just metres
+	return dist; // just meters
 }
 
 // rate in ft/min
diff --git a/html/geomag2020.js b/html/geomag2020.js
index 88c36fa..12c8461 100644
--- a/html/geomag2020.js
+++ b/html/geomag2020.js
@@ -159,7 +159,7 @@ function geoMagFactory(wmm) {
 			return date.getUTCFullYear() + (date.valueOf() - Date.UTC(year, 0)) / msInYear;
 		}
 
-		let alt = (h / 3280.8399) || 0, // convert h (in feet) to kilometres or set default of 0
+		let alt = (h / 3280.8399) || 0, // convert h (in feet) to kilometers or set default of 0
 			time = decimalDate(date),
 			dt = time - epoch,
 			rlat = deg2rad(glat),
diff --git a/html/script.js b/html/script.js
index 341225e..7b759dd 100644
--- a/html/script.js
+++ b/html/script.js
@@ -722,7 +722,7 @@ function initPage() {
     if (value = usp.getFloat('filterMaxRange')) {
         filterMaxRange = value;
     }
-    filterMaxRange *= 1852; // convert from nmi to metres
+    filterMaxRange *= 1852; // convert from nmi to meters
 
 
     if (value = usp.getFloat('mapOrientation')) {
@@ -1714,7 +1714,7 @@ function startPage() {
     // Make a LineString with 'points'-number points
     // that is a closed circle on the sphere such that the
     // great circle distance from 'center' to each point is
-    // 'radius' metres
+    // 'radius' meters
     utils.make_geodesic_circle = function (center, radius, points) {
         const angularDistance = radius / 6378137.0;
         const lon1 = center[0] * Math.PI / 180.0;
@@ -6073,7 +6073,7 @@ function drawUpintheair() {
     //  wget -O /usr/local/share/tar1090/html/upintheair.json \
     //    'http://www.heywhatsthat.com/api/upintheair.json?id=XXXX&refraction=0.25&alts=3048,9144'
     //
-    // NB: altitudes are in _metres_, you can specify a list of altitudes
+    // NB: altitudes are in _meters_, you can specify a list of altitudes
     //
     if (!calcOutlineData)
         return;
@@ -7400,7 +7400,7 @@ function coordsForExport(plane) {
             if (seg.ground) {
                 alt = "ground";
             } else if (alt != null && egmLoaded) {
-                // alt is in metres at this point
+                // alt is in meters at this point
                 alt = Math.round(egm96.ellipsoidToEgm96(pos[1], pos[0], alt));
             }