diff --git a/profile.d/pwd.sh b/profile.d/pwd.sh
index fba6b2a..7b52b48 100644
--- a/profile.d/pwd.sh
+++ b/profile.d/pwd.sh
@@ -273,43 +273,67 @@ export -f genpwd
 pwdscore()
 {
     local verbose=0
-    local PARSED
+    local read_stdin=0
+    local password=""
 
-    PARSED=$(getopt -o hv --long help,verbose -n 'pwdscore' -- "$@")
-    if [[ $? -ne 0 ]]; then return 1; fi
-    eval set -- "$PARSED"
-
-    while true; do
+    while [[ $# -gt 0 ]]; do
         case "$1" in
             -h|--help)
                 printf "pwdscore: Score a password from 1 to 100.\n\n"
-                printf "Usage: pwdscore [options] <password>\n\n"
+                printf "Usage: pwdscore [options] <password>\n"
+                printf "       pwdscore [options] --stdin\n"
+                printf "       pwdscore [options]            # prompt on terminal\n\n"
                 printf "Options:\n"
                 printf "\t-h, --help\t\tDisplay this help screen\n"
                 printf "\t-v, --verbose\t\tShow details about the computed score\n"
+                printf "\t-i, --stdin\t\tRead the password from standard input\n\n"
+                printf "Note:\n"
+                printf "  Passwords containing '!' should be quoted, or passed via --stdin.\n"
                 return 0
                 ;;
             -v|--verbose)
                 verbose=1
                 shift
                 ;;
+            -i|--stdin)
+                read_stdin=1
+                shift
+                ;;
             --)
                 shift
                 break
                 ;;
-            *)
-                disp E "Invalid options, use \"pwdscore --help\" to display usage."
+            -*)
+                disp E "Invalid option '$1'. Use \"pwdscore --help\" to display usage."
                 return 1
                 ;;
+            *)
+                break
+                ;;
         esac
     done
 
-    [[ $# -ne 1 ]] && {
-        disp E "Please provide exactly one password to score."
-        return 1
-    }
+    if (( read_stdin )); then
+        [[ $# -eq 0 ]] || {
+            disp E "Do not pass a positional password when using --stdin."
+            return 1
+        }
+        IFS= read -r password || true
+    elif [[ $# -eq 0 ]]; then
+        if [[ -t 0 ]]; then
+            read -r -s -p 'Password: ' password < /dev/tty || true
+            printf '\n' > /dev/tty
+        else
+            IFS= read -r password || true
+        fi
+    else
+        [[ $# -eq 1 ]] || {
+            disp E "Please provide exactly one password to score."
+            return 1
+        }
+        password="$1"
+    fi
 
-    local password="$1"
     local lower=${password,,}
     local length=${#password}
     local score=0
@@ -319,6 +343,9 @@ pwdscore()
     local c1=0 c2=0 c3=0
     local ch=""
     local has_lower=0 has_upper=0 has_digit=0 has_symbol=0
+    local pool_size=0
+    local entropy_bits="0.0"
+    local entropy_score=0
     local -A seen=()
 
     if [[ -z $password ]]; then
@@ -338,29 +365,66 @@ pwdscore()
         score=$(( length * 2 ))
     fi
 
-    [[ $password =~ [a-z] ]] && { has_lower=1; ((score += 12)); }
-    [[ $password =~ [A-Z] ]] && { has_upper=1; ((score += 12)); }
-    [[ $password =~ [0-9] ]] && { has_digit=1; ((score += 12)); }
-    [[ $password =~ [^[:alnum:]] ]] && { has_symbol=1; ((score += 14)); }
+    if [[ $password =~ [a-z] ]]; then
+        has_lower=1
+        pool_size=$(( pool_size + 26 ))
+        score=$(( score + 12 ))
+    fi
+    if [[ $password =~ [A-Z] ]]; then
+        has_upper=1
+        pool_size=$(( pool_size + 26 ))
+        score=$(( score + 12 ))
+    fi
+    if [[ $password =~ [0-9] ]]; then
+        has_digit=1
+        pool_size=$(( pool_size + 10 ))
+        score=$(( score + 12 ))
+    fi
+    if [[ $password =~ [^[:alnum:]] ]]; then
+        has_symbol=1
+        pool_size=$(( pool_size + 33 ))
+        score=$(( score + 14 ))
+    fi
 
     for (( i=0; i<length; i++ )); do
         ch=${password:i:1}
         if [[ -z ${seen["$ch"]+x} ]]; then
             seen["$ch"]=1
-            ((unique_count++))
+            unique_count=$(( unique_count + 1 ))
         fi
     done
-    (( score += (unique_count * 10) / length ))
+    score=$(( score + (unique_count * 10) / length ))
+
+    if (( pool_size > 1 )); then
+        entropy_bits=$(awk -v len="$length" -v pool="$pool_size" \
+            'BEGIN { printf "%.1f", len * (log(pool) / log(2)) }')
+
+        entropy_score=$(awk -v bits="$entropy_bits" 'BEGIN {
+            if (bits < 28) print -35;
+            else if (bits < 36) print -25;
+            else if (bits < 60) print -10;
+            else if (bits < 80) print 0;
+            else if (bits < 100) print 5;
+            else print 10;
+        }')
+        score=$(( score + entropy_score ))
+    fi
 
     if [[ $lower =~ (password|admin|root|qwerty|azerty|welcome|letmein|secret|changeme) ]]; then
-        ((score -= 25))
+        score=$(( score - 25 ))
     fi
     if [[ $lower =~ (1234|abcd|qwer|0000|1111|aaaa) ]]; then
-        ((score -= 15))
+        score=$(( score - 15 ))
+    fi
+    if [[ $password =~ (.)\1\1 ]]; then
+        score=$(( score - 10 ))
+    fi
+    if (( length < 8 )); then
+        score=$(( score - 10 ))
+    fi
+    if (( unique_count * 2 < length )); then
+        score=$(( score - 10 ))
     fi
-    [[ $password =~ (.)\1\1 ]] && ((score -= 10))
-    (( length < 8 )) && ((score -= 10))
-    (( unique_count * 2 < length )) && ((score -= 10))
 
     for (( idx=0; idx<length-2; idx++ )); do
         printf -v c1 '%d' "'${lower:idx:1}"
@@ -368,13 +432,16 @@ pwdscore()
         printf -v c3 '%d' "'${lower:idx+2:1}"
         if (( (c2 == c1 + 1 && c3 == c2 + 1) || \
               (c2 == c1 - 1 && c3 == c2 - 1) )); then
-            ((score -= 10))
+            score=$(( score - 10 ))
             break
         fi
     done
 
-    (( score < 1 )) && score=1
-    (( score > 100 )) && score=100
+    if (( score < 1 )); then
+        score=1
+    elif (( score > 100 )); then
+        score=100
+    fi
 
     if (( score >= 90 )); then
         rating='excellent'
@@ -397,6 +464,8 @@ pwdscore()
         printf 'Digits: %s\n' "$([[ $has_digit -eq 1 ]] && echo yes || echo no)"
         printf 'Symbols: %s\n' "$([[ $has_symbol -eq 1 ]] && echo yes || echo no)"
         printf 'Unique chars: %d\n' "$unique_count"
+        printf 'Entropy: ~%s bits\n' "$entropy_bits"
+        printf 'Entropy modifier: %+d\n' "$entropy_score"
     else
         printf '%d\n' "$score"
     fi