diff --git a/Cargo.toml b/Cargo.toml
index d206a7c..109a5a4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,4 +19,5 @@ clap = { version = "4.5.4", features = ["derive"] }
 fast32 = "1.0.2"
 libpt = { version = "0.5.1", features = ["bintols"], default-features = false }
 num = "0.4.3"
+rand = "0.8.5"
 
diff --git a/src/format.rs b/src/format.rs
index ebc59d1..6bc0ae3 100644
--- a/src/format.rs
+++ b/src/format.rs
@@ -86,6 +86,16 @@ pub struct FormatOptions {
     #[arg(short = 's', long)]
     /// format to base64
     base64: bool,
+    #[arg(short = 'r', long, default_value_t = 0, value_parser=numf_parser::<NumberType>)]
+    /// output random numbers
+    ///
+    /// Add a user defined amount of cryptographically pseudorandom numbers to the number list.
+    rand: NumberType,
+    #[arg(long, default_value_t = NumberType::MAX, value_parser=numf_parser::<NumberType>)]
+    /// max for the random numbers
+    ///
+    /// Generated numbers will not be lower than this. Only has an effect with --rand set.
+    rand_max: NumberType,
     #[arg(short = 'z', long)]
     /// format to base32
     base32: bool,
@@ -183,6 +193,26 @@ impl FormatOptions {
     pub fn push_number(&mut self, value: NumberType) {
         self.numbers.push(value)
     }
+
+    /// get rand
+    pub fn rand(&self) -> NumberType {
+        self.rand
+    }
+
+    /// set amount of extra random numbers manually
+    pub fn set_rand(&mut self, rand: NumberType) {
+        self.rand = rand;
+    }
+
+    /// get highes allowed random value
+    pub fn rand_max(&self) -> NumberType {
+        self.rand_max
+    }
+
+    /// set highes allowed random value
+    pub fn set_rand_max(&mut self, rand_max: NumberType) {
+        self.rand_max = rand_max;
+    }
 }
 
 impl Default for FormatOptions {
@@ -197,6 +227,8 @@ impl Default for FormatOptions {
             base64: false,
             dec: false,
             numbers: vec![],
+            rand: 0,
+            rand_max: NumberType::MAX,
         }
     }
 }
diff --git a/src/main.rs b/src/main.rs
index ca7e5ab..a8eabaa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,7 +12,7 @@ mod format;
 use format::*;
 use numf::format::numf_parser;
 
-fn main() {
+fn main() -> anyhow::Result<()> {
     // try to read from stdin first, appending the numbers we read to the FormatOptions
     let mut options = FormatOptions::parse();
     let mut stdin_nums = Vec::new();
@@ -23,6 +23,7 @@ fn main() {
                 let whole: String = match String::from_utf8(stdin_nums) {
                     Ok(r) => r,
                     Err(e) => {
+                        eprintln!("{}", FormatOptions::command().render_usage());
                         eprintln!("stdin for this program only accepts text: {e:#?}");
                         exit(1);
                     }
@@ -32,6 +33,7 @@ fn main() {
                     let number = match numf_parser(s) {
                         Ok(n) => n,
                         Err(e) => {
+                            eprintln!("{}", FormatOptions::command().render_usage());
                             eprintln!("could not parse number from stdin: {e:#?}");
                             exit(2);
                         }
@@ -40,14 +42,24 @@ fn main() {
                 }
             }
             Err(e) => {
+                eprintln!("{}", FormatOptions::command().render_usage());
                 eprintln!("could not read from stdin: {e:#?}");
                 exit(2);
             }
         };
     }
 
+    if options.rand() > 0 {
+        use rand::prelude::*;
+        let mut rand = rand::rngs::OsRng;
+        for _i in 0..options.rand() {
+            options.push_number(rand.gen_range(0..options.rand_max()));
+        }
+    }
+
     if options.numbers().is_empty() {
-        format!("{}", FormatOptions::command().render_usage());
+        eprintln!("{}", FormatOptions::command().render_usage());
+        eprintln!("no numbers have been provided");
         exit(1);
     }
 
@@ -59,4 +71,5 @@ fn main() {
     for o in out {
         println!("{o}")
     }
+    Ok(())
 }