diff --git a/src/hyperfine/benchmark.rs b/src/hyperfine/benchmark.rs
new file mode 100644
index 0000000..26ee651
--- /dev/null
+++ b/src/hyperfine/benchmark.rs
@@ -0,0 +1,197 @@
+use std::io;
+use std::process::{Command, Stdio};
+use std::time::Instant;
+
+use ansi_term::Colour::{Cyan, Green, White, Yellow};
+
+use hyperfine::internal::{get_progress_bar, HyperfineOptions, Second, Warnings, MIN_EXECUTION_TIME};
+use hyperfine::statistics::mean;
+
+/// Results from timing a single shell command
+pub struct TimingResult {
+    /// Execution time in seconds
+    pub execution_time_sec: Second,
+
+    /// True if the command finished with exit code zero
+    pub success: bool,
+}
+
+impl TimingResult {
+    fn new(execution_time_sec: Second, success: bool) -> TimingResult {
+        TimingResult {
+            execution_time_sec,
+            success,
+        }
+    }
+}
+
+/// Run the given shell command and measure the execution time
+pub fn time_shell_command(shell_cmd: &str, ignore_failure: bool) -> io::Result<TimingResult> {
+    let start = Instant::now();
+
+    let status = Command::new("sh")
+        .arg("-c")
+        .arg(shell_cmd)
+        .stdin(Stdio::null())
+        .stdout(Stdio::null())
+        .stderr(Stdio::null())
+        .status()?;
+
+    if !ignore_failure && !status.success() {
+        return Err(io::Error::new(
+            io::ErrorKind::Other,
+            "Command terminated with non-zero exit code. \
+             Use the '-i'/'--ignore-failure' option if you want to ignore this.",
+        ));
+    }
+
+    let duration = start.elapsed();
+
+    let execution_time_sec = duration.as_secs() as f64 + duration.subsec_nanos() as f64 * 1e-9;
+
+    Ok(TimingResult::new(execution_time_sec, status.success()))
+}
+
+/// Measure the average shell spawning time
+pub fn mean_shell_spawning_time() -> io::Result<Second> {
+    const COUNT: u64 = 200;
+    let bar = get_progress_bar(COUNT, "Measuring shell spawning time");
+
+    let mut times: Vec<Second> = vec![];
+    for _ in 0..COUNT {
+        let res = time_shell_command("", false);
+
+        match res {
+            Err(_) => {
+                return Err(io::Error::new(
+                    io::ErrorKind::Other,
+                    "Could not measure shell execution time. \
+                     Make sure you can run 'sh -c \"\"'.",
+                ))
+            }
+            Ok(r) => {
+                times.push(r.execution_time_sec);
+            }
+        }
+        bar.inc(1);
+    }
+    bar.finish_and_clear();
+
+    let mean: f64 = mean(times.iter().cloned()); // TODO: get rid of .cloned()
+    Ok(mean)
+}
+
+/// Run the benchmark for a single shell command
+pub fn run_benchmark(
+    num: usize,
+    cmd: &str,
+    shell_spawning_time: Second,
+    options: &HyperfineOptions,
+) -> io::Result<()> {
+    // Helper function to compute corrected execution times
+    let get_execution_time = |r: &TimingResult| -> Second {
+        if r.execution_time_sec < shell_spawning_time {
+            0.0
+        } else {
+            r.execution_time_sec - shell_spawning_time
+        }
+    };
+
+    println!(
+        "{}{}: {}",
+        White.bold().paint("Benchmark #"),
+        White.bold().paint((num + 1).to_string()),
+        Cyan.paint(cmd)
+    );
+    println!();
+
+    let mut results = vec![];
+
+    // Warmup phase
+    if options.warmup_count > 0 {
+        let bar = get_progress_bar(options.warmup_count, "Performing warmup runs");
+
+        for _ in 0..options.warmup_count {
+            let _ = time_shell_command(cmd, options.ignore_failure)?;
+            bar.inc(1);
+        }
+        bar.finish_and_clear();
+    }
+
+    // Set up progress bar (and spinner for initial measurement)
+    let bar = get_progress_bar(options.min_runs, "Initial time measurement");
+
+    // Initial timing run
+    let res = time_shell_command(cmd, options.ignore_failure)?;
+
+    // Determine number of benchmark runs
+    let runs_in_min_time = (options.min_time_sec / res.execution_time_sec) as u64;
+
+    let count = if runs_in_min_time >= options.min_runs {
+        runs_in_min_time
+    } else {
+        options.min_runs
+    };
+
+    let count_remaining = count - 1;
+
+    // Save the first result
+    results.push(res);
+
+    // Re-configure the progress bar
+    bar.set_length(count_remaining);
+
+    // Gather statistics
+    for _ in 0..count_remaining {
+        let msg = {
+            let execution_times = results.iter().map(&get_execution_time);
+            let mean = format!("{:.3} s", mean(execution_times));
+            format!("Current estimate: {:.3}", Green.paint(mean))
+        };
+        bar.set_message(&msg);
+
+        let res = time_shell_command(cmd, options.ignore_failure)?;
+        results.push(res);
+        bar.inc(1);
+    }
+    bar.finish_and_clear();
+
+    // Compute statistical quantities
+
+    // Corrected execution times
+    let execution_times = results.iter().map(&get_execution_time);
+
+    let t_mean = mean(execution_times.clone());
+    let t2_mean = mean(execution_times.clone().map(|t| t.powi(2)));
+
+    let stddev = (t2_mean - t_mean.powi(2)).sqrt();
+
+    // Formatting and console output
+    let time_fmt = format!("{:.3} s ± {:.3} s", t_mean, stddev);
+
+    println!("  Time: {}", Green.paint(time_fmt));
+
+    // Warnings
+    let mut warnings = vec![];
+
+    // Check execution time
+    if execution_times.clone().any(|t| t < MIN_EXECUTION_TIME) {
+        warnings.push(Warnings::FastExecutionTime);
+    }
+
+    // Check programm exit codes
+    if results.iter().any(|r| !r.success) {
+        warnings.push(Warnings::NonZeroExitCode);
+    }
+
+    if warnings.len() > 0 {
+        eprintln!();
+        for warning in &warnings {
+            eprintln!("  {}: {}", Yellow.paint("Warning"), warning);
+        }
+    }
+
+    println!();
+
+    Ok(())
+}
diff --git a/src/hyperfine/internal.rs b/src/hyperfine/internal.rs
new file mode 100644
index 0000000..07ac952
--- /dev/null
+++ b/src/hyperfine/internal.rs
@@ -0,0 +1,68 @@
+use std::fmt;
+
+use indicatif::{ProgressBar, ProgressStyle};
+
+/// Type alias for unit of time
+pub type Second = f64;
+
+/// Threshold for warning about fast execution time
+pub const MIN_EXECUTION_TIME: Second = 5e-3;
+
+/// A set of options for hyperfine
+pub struct HyperfineOptions {
+    /// Number of warmup runs
+    pub warmup_count: u64,
+
+    /// Minimum number of benchmark runs
+    pub min_runs: u64,
+
+    /// Minimum benchmarking time
+    pub min_time_sec: Second,
+
+    /// Whether or not to ignore non-zero exit codes
+    pub ignore_failure: bool,
+}
+
+impl Default for HyperfineOptions {
+    fn default() -> HyperfineOptions {
+        HyperfineOptions {
+            warmup_count: 0,
+            min_runs: 10,
+            min_time_sec: 3.0,
+            ignore_failure: false,
+        }
+    }
+}
+
+/// Return a pre-configured progress bar
+pub fn get_progress_bar(length: u64, msg: &str) -> ProgressBar {
+    let progressbar_style = ProgressStyle::default_spinner()
+        .tick_chars("⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏")
+        .template(" {spinner} {msg:<30} {wide_bar} ETA {eta_precise}");
+
+    let bar = ProgressBar::new(length);
+    bar.set_style(progressbar_style.clone());
+    bar.enable_steady_tick(80);
+    bar.set_message(msg);
+
+    bar
+}
+
+/// Possible benchmark warnings
+pub enum Warnings {
+    FastExecutionTime,
+    NonZeroExitCode,
+}
+
+impl fmt::Display for Warnings {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            &Warnings::FastExecutionTime => write!(
+                f,
+                "Command took less than {:.0} ms to complete. Results might be inaccurate.",
+                MIN_EXECUTION_TIME * 1e3
+            ),
+            &Warnings::NonZeroExitCode => write!(f, "Ignoring non-zero exit code."),
+        }
+    }
+}
diff --git a/src/hyperfine/mod.rs b/src/hyperfine/mod.rs
new file mode 100644
index 0000000..62c63f0
--- /dev/null
+++ b/src/hyperfine/mod.rs
@@ -0,0 +1,3 @@
+pub mod benchmark;
+pub mod internal;
+pub mod statistics;
diff --git a/src/hyperfine/statistics.rs b/src/hyperfine/statistics.rs
new file mode 100644
index 0000000..4758025
--- /dev/null
+++ b/src/hyperfine/statistics.rs
@@ -0,0 +1,13 @@
+/// Calculate statistical average
+pub fn mean<I>(values: I) -> f64
+where
+    I: IntoIterator<Item = f64>,
+{
+    let mut sum: f64 = 0.0;
+    let mut len: u64 = 0;
+    for v in values {
+        sum += v;
+        len += 1;
+    }
+    sum / (len as f64)
+}
diff --git a/src/main.rs b/src/main.rs
index a4a042b..f94256f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,19 +6,14 @@ extern crate indicatif;
 use std::cmp;
 use std::error::Error;
 use std::io;
-use std::process::{Command, Stdio};
-use std::time::Instant;
-use std::fmt;
 
-use indicatif::{ProgressBar, ProgressStyle};
-use ansi_term::Colour::{Cyan, Green, Red, White, Yellow};
+use ansi_term::Colour::Red;
 use clap::{App, AppSettings, Arg};
 
-/// Type alias for unit of time
-type Second = f64;
+mod hyperfine;
 
-/// Threshold for warning about fast execution time
-const MIN_EXECUTION_TIME: Second = 5e-3;
+use hyperfine::internal::HyperfineOptions;
+use hyperfine::benchmark::{mean_shell_spawning_time, run_benchmark};
 
 /// Print error message to stderr and terminate
 pub fn error(message: &str) -> ! {
@@ -26,241 +21,6 @@ pub fn error(message: &str) -> ! {
     std::process::exit(1);
 }
 
-struct CmdResult {
-    /// Execution time in seconds
-    execution_time_sec: Second,
-
-    /// True if the command finished with exit code zero
-    success: bool,
-}
-
-impl CmdResult {
-    fn new(execution_time_sec: Second, success: bool) -> CmdResult {
-        CmdResult {
-            execution_time_sec,
-            success,
-        }
-    }
-}
-
-/// Run the given shell command and measure the execution time
-fn time_shell_command(shell_cmd: &str, ignore_failure: bool) -> io::Result<CmdResult> {
-    let start = Instant::now();
-
-    let status = Command::new("sh")
-        .arg("-c")
-        .arg(shell_cmd)
-        .stdin(Stdio::null())
-        .stdout(Stdio::null())
-        .stderr(Stdio::null())
-        .status()?;
-
-    if !ignore_failure && !status.success() {
-        return Err(io::Error::new(
-            io::ErrorKind::Other,
-            "Command terminated with non-zero exit code. \
-             Use the '-i'/'--ignore-failure' option if you want to ignore this.",
-        ));
-    }
-
-    let duration = start.elapsed();
-
-    let execution_time_sec = duration.as_secs() as f64 + duration.subsec_nanos() as f64 * 1e-9;
-
-    Ok(CmdResult::new(execution_time_sec, status.success()))
-}
-
-/// Return a pre-configured progress bar
-fn get_progress_bar(length: u64, msg: &str) -> ProgressBar {
-    let progressbar_style = ProgressStyle::default_spinner()
-        .tick_chars("⠋⠙⠹⠸⠼⠴⠦⠧⠇⠏")
-        .template(" {spinner} {msg:<30} {wide_bar} ETA {eta_precise}");
-
-    let bar = ProgressBar::new(length);
-    bar.set_style(progressbar_style.clone());
-    bar.enable_steady_tick(80);
-    bar.set_message(msg);
-
-    bar
-}
-
-/// Possible benchmark warnings
-enum Warnings {
-    FastExecutionTime,
-    NonZeroExitCode,
-}
-
-impl fmt::Display for Warnings {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match self {
-            &Warnings::FastExecutionTime => write!(
-                f,
-                "Command took less than {:.0} ms to complete. Results might be inaccurate.",
-                MIN_EXECUTION_TIME * 1e3
-            ),
-            &Warnings::NonZeroExitCode => write!(f, "Ignoring non-zero exit code."),
-        }
-    }
-}
-
-/// Calculate statistical average
-fn mean<I>(values: I) -> f64
-where
-    I: IntoIterator<Item = f64>,
-{
-    let mut sum: f64 = 0.0;
-    let mut len: u64 = 0;
-    for v in values {
-        sum += v;
-        len += 1;
-    }
-    sum / (len as f64)
-}
-
-/// Run the benchmark for a single shell command
-fn run_benchmark(
-    num: usize,
-    cmd: &str,
-    shell_spawning_time: Second,
-    options: &HyperfineOptions,
-) -> io::Result<()> {
-    // Helper function to compute corrected execution times
-    let get_execution_time = |r: &CmdResult| -> Second {
-        if r.execution_time_sec < shell_spawning_time {
-            0.0
-        } else {
-            r.execution_time_sec - shell_spawning_time
-        }
-    };
-
-    println!(
-        "{}{}: {}",
-        White.bold().paint("Benchmark #"),
-        White.bold().paint((num + 1).to_string()),
-        Cyan.paint(cmd)
-    );
-    println!();
-
-    let mut results = vec![];
-
-    // Warmup phase
-    if options.warmup_count > 0 {
-        let bar = get_progress_bar(options.warmup_count, "Performing warmup runs");
-
-        for _ in 0..options.warmup_count {
-            let _ = time_shell_command(cmd, options.ignore_failure)?;
-            bar.inc(1);
-        }
-        bar.finish_and_clear();
-    }
-
-    // Set up progress bar (and spinner for initial measurement)
-    let bar = get_progress_bar(options.min_runs, "Initial time measurement");
-
-    // Initial timing run
-    let res = time_shell_command(cmd, options.ignore_failure)?;
-
-    // Determine number of benchmark runs
-    let runs_in_min_time = (options.min_time_sec / res.execution_time_sec) as u64;
-
-    let count = if runs_in_min_time >= options.min_runs {
-        runs_in_min_time
-    } else {
-        options.min_runs
-    };
-
-    let count_remaining = count - 1;
-
-    // Save the first result
-    results.push(res);
-
-    // Re-configure the progress bar
-    bar.set_length(count_remaining);
-
-    // Gather statistics
-    for _ in 0..count_remaining {
-        let msg = {
-            let execution_times = results.iter().map(&get_execution_time);
-            let mean = format!("{:.3} s", mean(execution_times));
-            format!("Current estimate: {:.3}", Green.paint(mean))
-        };
-        bar.set_message(&msg);
-
-        let res = time_shell_command(cmd, options.ignore_failure)?;
-        results.push(res);
-        bar.inc(1);
-    }
-    bar.finish_and_clear();
-
-    // Compute statistical quantities
-
-    // Corrected execution times
-    let execution_times = results.iter().map(&get_execution_time);
-
-    let t_mean = mean(execution_times.clone());
-    let t2_mean = mean(execution_times.clone().map(|t| t.powi(2)));
-
-    let stddev = (t2_mean - t_mean.powi(2)).sqrt();
-
-    // Formatting and console output
-    let time_fmt = format!("{:.3} s ± {:.3} s", t_mean, stddev);
-
-    println!("  Time: {}", Green.paint(time_fmt));
-
-    // Warnings
-    let mut warnings = vec![];
-
-    // Check execution time
-    if execution_times.clone().any(|t| t < MIN_EXECUTION_TIME) {
-        warnings.push(Warnings::FastExecutionTime);
-    }
-
-    // Check programm exit codes
-    if results.iter().any(|r| !r.success) {
-        warnings.push(Warnings::NonZeroExitCode);
-    }
-
-    if warnings.len() > 0 {
-        eprintln!();
-        for warning in &warnings {
-            eprintln!("  {}: {}", Yellow.paint("Warning"), warning);
-        }
-    }
-
-    println!();
-
-    Ok(())
-}
-
-// Measure the average shell spawning time
-fn mean_shell_spawning_time() -> io::Result<Second> {
-    const COUNT: u64 = 200;
-    let bar = get_progress_bar(COUNT, "Measuring shell spawning time");
-
-    let mut times: Vec<Second> = vec![];
-    for _ in 0..COUNT {
-        let res = time_shell_command("", false);
-
-        match res {
-            Err(_) => {
-                return Err(io::Error::new(
-                    io::ErrorKind::Other,
-                    "Could not measure shell execution time. \
-                     Make sure you can run 'sh -c \"\"'.",
-                ))
-            }
-            Ok(r) => {
-                times.push(r.execution_time_sec);
-            }
-        }
-        bar.inc(1);
-    }
-    bar.finish_and_clear();
-
-    let mean: f64 = mean(times.iter().cloned()); // TODO: get rid of .cloned()
-    Ok(mean)
-}
-
 /// Runs the benchmark for the given commands
 fn run(commands: &Vec<&str>, options: &HyperfineOptions) -> io::Result<()> {
     let shell_spawning_time = mean_shell_spawning_time()?;
@@ -273,31 +33,6 @@ fn run(commands: &Vec<&str>, options: &HyperfineOptions) -> io::Result<()> {
     Ok(())
 }
 
-pub struct HyperfineOptions {
-    /// Number of warmup runs
-    pub warmup_count: u64,
-
-    /// Minimum number of benchmark runs
-    pub min_runs: u64,
-
-    /// Minimum benchmarking time
-    pub min_time_sec: Second,
-
-    /// Whether or not to ignore non-zero exit codes
-    pub ignore_failure: bool,
-}
-
-impl Default for HyperfineOptions {
-    fn default() -> HyperfineOptions {
-        HyperfineOptions {
-            warmup_count: 0,
-            min_runs: 10,
-            min_time_sec: 3.0,
-            ignore_failure: false,
-        }
-    }
-}
-
 fn main() {
     let matches = App::new("hyperfine")
         .version(crate_version!())