diff --git a/cmd/tafparser/main.go b/cmd/tafparser/main.go
index eff8cc3..23108e6 100644
--- a/cmd/tafparser/main.go
+++ b/cmd/tafparser/main.go
@@ -19,8 +19,8 @@ func init() {
 func main() {
 	pretty := pflag.BoolP("pretty", "p", true, "Pretty-print the JSON output")
 	printGo := pflag.BoolP("print-go", "G", false, "Print Go code instead of JSON")
-	convertDist := pflag.StringP("convert-distance", "d", "", "Convert all the distances to the given unit. (valid units: sm, mi, m)")
-	convertSpd := pflag.StringP("convert-speed", "s", "", "Convert all the speeds to the given unit. (valid units: m/s, mps, kmh, kph, kt, kts)")
+	convertDist := pflag.StringP("convert-distance", "d", "", "Convert all the distances to the given unit. (valid units: mi, m, km)")
+	convertSpd := pflag.StringP("convert-speed", "s", "", "Convert all the speeds to the given unit. (valid units: m/s, kph, kts, mph)")
 	pflag.Parse()
 
 	var opts taf.Options
diff --git a/units/units.go b/units/units.go
index bcd6754..3297a6e 100644
--- a/units/units.go
+++ b/units/units.go
@@ -12,6 +12,7 @@ const (
 	MetersPerSecond   Speed = "MetersPerSecond"
 	KilometersPerHour Speed = "KilometersPerHour"
 	Knots             Speed = "Knots"
+	MilesPerHour      Speed = "MilesPerHour"
 )
 
 // Convert converts a value from one unit to another
@@ -29,22 +30,36 @@ func (sf Speed) Convert(st Speed, val int) int {
 		return int(float64(val) * 1.94384)
 	case sf == Knots && st == MetersPerSecond:
 		return int(float64(val) / 1.94384)
+	case sf == MilesPerHour && st == KilometersPerHour:
+		return int(float64(val) * 1.60934)
+	case sf == KilometersPerHour && st == MilesPerHour:
+		return int(float64(val) / 1.60934)
+	case sf == MilesPerHour && st == MetersPerSecond:
+		return int(float64(val) * 0.44704)
+	case sf == MetersPerSecond && st == MilesPerHour:
+		return int(float64(val) / 0.44704)
+	case sf == MilesPerHour && st == Knots:
+		return int(float64(val) * 0.868976)
+	case sf == Knots && st == MilesPerHour:
+		return int(float64(val) / 0.868976)
 	default:
 		return val
 	}
 }
 
 // ParseSpeed parses a speed value. Valid inputs include:
-// mps, m/s, kmh, kph, kt, and kts.
+// mps, m/s, kmh, kph, kt, kts, mph, and milesperhour.
 // This function is case-insensitive.
 func ParseSpeed(s string) (Speed, bool) {
 	switch strings.ToLower(s) {
-	case "m/s", "mps", "meterspersecond", "meters per second":
+	case "m/s", "mps", "meterspersecond", "meters per second", "metrespersecond", "metres per second":
 		return MetersPerSecond, true
-	case "kmh", "kph", "km/h", "kilometersperhour", "kilometers per hour":
+	case "kmh", "kph", "km/h", "kilometersperhour", "kilometers per hour", "kilometresperhour", "kilometres per hour":
 		return KilometersPerHour, true
 	case "kt", "kts", "knot", "knots":
 		return Knots, true
+	case "mph", "milesperhour", "miles per hour":
+		return MilesPerHour, true
 	default:
 		return "", false
 	}
@@ -55,8 +70,9 @@ type Distance string
 
 // Distance units
 const (
-	Miles  Distance = "Miles"
-	Meters Distance = "Meters"
+	Miles      Distance = "Miles"
+	Meters     Distance = "Meters"
+	Kilometers Distance = "Kilometers"
 )
 
 // Convert converts a value from one unit to another
@@ -66,19 +82,30 @@ func (df Distance) Convert(dt Distance, val float64) float64 {
 		return val * 1609
 	case df == Meters && dt == Miles:
 		return val / 1609
+	case df == Kilometers && dt == Meters:
+		return val * 1000
+	case df == Meters && dt == Kilometers:
+		return val / 1000
+	case df == Miles && dt == Kilometers:
+		return val * 1.60934
+	case df == Kilometers && dt == Miles:
+		return val / 1.60934
 	default:
 		return val
 	}
 }
 
-// ParseDistance parses a speed value. Valid inputs include:
-// sm, mi, and m. This function is case-insensitive.
+// ParseDistance parses a distance value. Valid inputs include:
+// sm, mi, m, km, and kilometers.
+// This function is case-insensitive.
 func ParseDistance(s string) (Distance, bool) {
 	switch strings.ToLower(s) {
 	case "sm", "mi", "mile", "miles":
 		return Miles, true
-	case "m", "meter", "meters":
+	case "m", "meter", "meters", "metre", "metres":
 		return Meters, true
+	case "km", "kilometer", "kilometers", "kilometre", "kilometres":
+		return Kilometers, true
 	default:
 		return "", false
 	}