diff --git a/src/benchmark.rs b/src/benchmark.rs
index 7f0d1e9..301443c 100644
--- a/src/benchmark.rs
+++ b/src/benchmark.rs
@@ -391,10 +391,11 @@ pub fn run_benchmark(
     // Compute statistical quantities
     let t_num = times_real.len();
     let t_mean = mean(&times_real);
-    let mut t_stddev = 0.0;
-    if times_real.len() != 1 {
-        t_stddev = standard_deviation(&times_real, Some(t_mean));
-    }
+    let t_stddev = if times_real.len() > 1 {
+        Some(standard_deviation(&times_real, Some(t_mean)))
+    } else {
+        None
+    };
     let t_median = median(&times_real);
     let t_min = min(&times_real);
     let t_max = max(&times_real);
@@ -404,7 +405,6 @@ pub fn run_benchmark(
 
     // Formatting and console output
     let (mean_str, time_unit) = format_duration_unit(t_mean, options.time_unit);
-    let stddev_str = format_duration(t_stddev, Some(time_unit));
     let min_str = format_duration(t_min, Some(time_unit));
     let max_str = format_duration(t_max, Some(time_unit));
     let num_str = format!("{} runs", t_num);
@@ -412,34 +412,38 @@ pub fn run_benchmark(
     let user_str = format_duration(user_mean, Some(time_unit));
     let system_str = format_duration(system_mean, Some(time_unit));
 
-    if options.output_style != OutputStyleOption::Disabled && times_real.len() == 1 {
-        println!(
-            "  Time ({} ≡):        {:>8}  {:>8}     [User: {}, System: {}]",
-            "abs".green().bold(),
-            mean_str.green().bold(),
-            "        ".to_string(), // alignment
-            user_str.blue(),
-            system_str.blue()
-        );
-    } else if options.output_style != OutputStyleOption::Disabled {
-        println!(
-            "  Time ({} ± {}):     {:>8} ± {:>8}    [User: {}, System: {}]",
-            "mean".green().bold(),
-            "σ".green(),
-            mean_str.green().bold(),
-            stddev_str.green(),
-            user_str.blue(),
-            system_str.blue()
-        );
+    if options.output_style != OutputStyleOption::Disabled {
+        if times_real.len() == 1 {
+            println!(
+                "  Time ({} ≡):        {:>8}  {:>8}     [User: {}, System: {}]",
+                "abs".green().bold(),
+                mean_str.green().bold(),
+                "        ".to_string(), // alignment
+                user_str.blue(),
+                system_str.blue()
+            );
+        } else {
+            let stddev_str = format_duration(t_stddev.unwrap(), Some(time_unit));
 
-        println!(
-            "  Range ({} … {}):   {:>8} … {:>8}    {}",
-            "min".cyan(),
-            "max".purple(),
-            min_str.cyan(),
-            max_str.purple(),
-            num_str.dimmed()
-        );
+            println!(
+                "  Time ({} ± {}):     {:>8} ± {:>8}    [User: {}, System: {}]",
+                "mean".green().bold(),
+                "σ".green(),
+                mean_str.green().bold(),
+                stddev_str.green(),
+                user_str.blue(),
+                system_str.blue()
+            );
+
+            println!(
+                "  Range ({} … {}):   {:>8} … {:>8}    {}",
+                "min".cyan(),
+                "max".purple(),
+                min_str.cyan(),
+                max_str.purple(),
+                num_str.dimmed()
+            );
+        }
     }
 
     // Warnings
diff --git a/src/benchmark_result.rs b/src/benchmark_result.rs
index b47bbfd..72f8483 100644
--- a/src/benchmark_result.rs
+++ b/src/benchmark_result.rs
@@ -15,8 +15,8 @@ pub struct BenchmarkResult {
     /// The mean run time
     pub mean: Second,
 
-    /// The standard deviation of all run times
-    pub stddev: Second,
+    /// The standard deviation of all run times. Not available if only one run has been performed
+    pub stddev: Option<Second>,
 
     /// The median run time
     pub median: Second,
@@ -51,7 +51,7 @@ impl BenchmarkResult {
     pub fn new(
         command: String,
         mean: Second,
-        stddev: Second,
+        stddev: Option<Second>,
         median: Second,
         user: Second,
         system: Second,
diff --git a/src/export/asciidoc.rs b/src/export/asciidoc.rs
index 8afafa9..8ce14b5 100644
--- a/src/export/asciidoc.rs
+++ b/src/export/asciidoc.rs
@@ -60,7 +60,7 @@ fn table_row(entry: &BenchmarkResult, unit: Unit) -> Vec<u8> {
          | {}…{}\n",
         entry.command.replace("|", "\\|"),
         form(entry.mean).0,
-        form(entry.stddev).0,
+        entry.stddev.map(|s| form(s).0).unwrap_or("?".into()),
         form(entry.min).0,
         form(entry.max).0
     )
@@ -84,14 +84,14 @@ fn test_asciidoc_header() {
 fn test_asciidoc_table_row() {
     use std::collections::BTreeMap;
     let result = BenchmarkResult::new(
-        String::from("sleep 1"), // command
-        0.10491992406666667,     // mean
-        0.00397851689425097,     // stddev
-        0.10491992406666667,     // median
-        0.005182013333333333,    // user
-        0.0,                     // system
-        0.1003342584,            // min
-        0.10745223440000001,     // max
+        String::from("sleep 1"),   // command
+        0.10491992406666667,       // mean
+        Some(0.00397851689425097), // stddev
+        0.10491992406666667,       // median
+        0.005182013333333333,      // user
+        0.0,                       // system
+        0.1003342584,              // min
+        0.10745223440000001,       // max
         vec![
             // times
             0.1003342584,
@@ -108,7 +108,7 @@ fn test_asciidoc_table_row() {
          | {}…{}\n",
         result.command,
         Unit::MilliSecond.format(result.mean),
-        Unit::MilliSecond.format(result.stddev),
+        Unit::MilliSecond.format(result.stddev.unwrap()),
         Unit::MilliSecond.format(result.min),
         Unit::MilliSecond.format(result.max)
     )
@@ -119,7 +119,7 @@ fn test_asciidoc_table_row() {
          | {}…{}\n",
         result.command,
         Unit::Second.format(result.mean),
-        Unit::Second.format(result.stddev),
+        Unit::Second.format(result.stddev.unwrap()),
         Unit::Second.format(result.min),
         Unit::Second.format(result.max)
     )
@@ -137,14 +137,14 @@ fn test_asciidoc_table_row() {
 fn test_asciidoc_table_row_command_escape() {
     use std::collections::BTreeMap;
     let result = BenchmarkResult::new(
-        String::from("sleep 1|"), // command
-        0.10491992406666667,      // mean
-        0.00397851689425097,      // stddev
-        0.10491992406666667,      // median
-        0.005182013333333333,     // user
-        0.0,                      // system
-        0.1003342584,             // min
-        0.10745223440000001,      // max
+        String::from("sleep 1|"),  // command
+        0.10491992406666667,       // mean
+        Some(0.00397851689425097), // stddev
+        0.10491992406666667,       // median
+        0.005182013333333333,      // user
+        0.0,                       // system
+        0.1003342584,              // min
+        0.10745223440000001,       // max
         vec![
             // times
             0.1003342584,
@@ -159,7 +159,7 @@ fn test_asciidoc_table_row_command_escape() {
          | {} ± {}\n\
          | {}…{}\n",
         Unit::Second.format(result.mean),
-        Unit::Second.format(result.stddev),
+        Unit::Second.format(result.stddev.unwrap()),
         Unit::Second.format(result.min),
         Unit::Second.format(result.max)
     )
@@ -179,7 +179,7 @@ fn test_asciidoc() {
         BenchmarkResult::new(
             String::from("FOO=1 BAR=2 command | 1"),
             1.0,
-            2.0,
+            Some(2.0),
             1.0,
             3.0,
             4.0,
@@ -197,7 +197,7 @@ fn test_asciidoc() {
         BenchmarkResult::new(
             String::from("FOO=1 BAR=7 command | 2"),
             11.0,
-            12.0,
+            Some(12.0),
             11.0,
             13.0,
             14.0,
diff --git a/src/export/csv.rs b/src/export/csv.rs
index a954a93..435b4d6 100644
--- a/src/export/csv.rs
+++ b/src/export/csv.rs
@@ -33,7 +33,13 @@ impl Exporter for CsvExporter {
         for res in results {
             let mut fields = vec![Cow::Borrowed(res.command.as_bytes())];
             for f in &[
-                res.mean, res.stddev, res.median, res.user, res.system, res.min, res.max,
+                res.mean,
+                res.stddev.unwrap_or(0.0),
+                res.median,
+                res.user,
+                res.system,
+                res.min,
+                res.max,
             ] {
                 fields.push(Cow::Owned(f.to_string().into_bytes()))
             }
@@ -59,7 +65,7 @@ fn test_csv() {
         BenchmarkResult::new(
             String::from("FOO=one BAR=two command | 1"),
             1.0,
-            2.0,
+            Some(2.0),
             1.0,
             3.0,
             4.0,
@@ -77,7 +83,7 @@ fn test_csv() {
         BenchmarkResult::new(
             String::from("FOO=one BAR=seven command | 2"),
             11.0,
-            12.0,
+            Some(12.0),
             11.0,
             13.0,
             14.0,
diff --git a/src/export/markdown.rs b/src/export/markdown.rs
index 302915f..0999767 100644
--- a/src/export/markdown.rs
+++ b/src/export/markdown.rs
@@ -53,19 +53,27 @@ fn start_table(unit: Unit) -> Vec<u8> {
 fn add_table_row(dest: &mut Vec<u8>, entry: &BenchmarkResultWithRelativeSpeed, unit: Unit) {
     let result = &entry.result;
     let mean_str = format_duration_value(result.mean, Some(unit)).0;
-    let stddev_str = format_duration_value(result.stddev, Some(unit)).0;
+    let stddev_str = if let Some(stddev) = result.stddev {
+        format!(" ± {}", format_duration_value(stddev, Some(unit)).0)
+    } else {
+        "".into()
+    };
     let min_str = format_duration_value(result.min, Some(unit)).0;
     let max_str = format_duration_value(result.max, Some(unit)).0;
     let rel_str = format!("{:.2}", entry.relative_speed);
     let rel_stddev_str = if entry.is_fastest {
         "".into()
     } else {
-        format!(" ± {:.2}", entry.relative_speed_stddev)
+        if let Some(stddev) = entry.relative_speed_stddev {
+            format!(" ± {:.2}", stddev)
+        } else {
+            "".into()
+        }
     };
 
     dest.extend(
         format!(
-            "| `{command}` | {mean} ± {stddev} | {min} | {max} | {rel}{rel_stddev} |\n",
+            "| `{command}` | {mean}{stddev} | {min} | {max} | {rel}{rel_stddev} |\n",
             command = result.command.replace("|", "\\|"),
             mean = mean_str,
             stddev = stddev_str,
@@ -93,7 +101,7 @@ fn test_markdown_format_ms() {
         BenchmarkResult::new(
             String::from("sleep 0.1"),
             0.1057,                          // mean
-            0.0016,                          // std dev
+            Some(0.0016),                    // std dev
             0.1057,                          // median
             0.0009,                          // user_mean
             0.0011,                          // system_mean
@@ -106,7 +114,7 @@ fn test_markdown_format_ms() {
         BenchmarkResult::new(
             String::from("sleep 2"),
             2.0050,                          // mean
-            0.0020,                          // std dev
+            Some(0.0020),                    // std dev
             2.0050,                          // median
             0.0009,                          // user_mean
             0.0012,                          // system_mean
@@ -142,7 +150,7 @@ fn test_markdown_format_s() {
         BenchmarkResult::new(
             String::from("sleep 2"),
             2.0050,                          // mean
-            0.0020,                          // std dev
+            Some(0.0020),                    // std dev
             2.0050,                          // median
             0.0009,                          // user_mean
             0.0012,                          // system_mean
@@ -155,7 +163,7 @@ fn test_markdown_format_s() {
         BenchmarkResult::new(
             String::from("sleep 0.1"),
             0.1057,                          // mean
-            0.0016,                          // std dev
+            Some(0.0016),                    // std dev
             0.1057,                          // median
             0.0009,                          // user_mean
             0.0011,                          // system_mean
@@ -190,7 +198,7 @@ fn test_markdown_format_time_unit_s() {
         BenchmarkResult::new(
             String::from("sleep 0.1"),
             0.1057,                          // mean
-            0.0016,                          // std dev
+            Some(0.0016),                    // std dev
             0.1057,                          // median
             0.0009,                          // user_mean
             0.0011,                          // system_mean
@@ -203,7 +211,7 @@ fn test_markdown_format_time_unit_s() {
         BenchmarkResult::new(
             String::from("sleep 2"),
             2.0050,                          // mean
-            0.0020,                          // std dev
+            Some(0.0020),                    // std dev
             2.0050,                          // median
             0.0009,                          // user_mean
             0.0012,                          // system_mean
@@ -244,7 +252,7 @@ fn test_markdown_format_time_unit_ms() {
         BenchmarkResult::new(
             String::from("sleep 2"),
             2.0050,                          // mean
-            0.0020,                          // std dev
+            Some(0.0020),                    // std dev
             2.0050,                          // median
             0.0009,                          // user_mean
             0.0012,                          // system_mean
@@ -257,7 +265,7 @@ fn test_markdown_format_time_unit_ms() {
         BenchmarkResult::new(
             String::from("sleep 0.1"),
             0.1057,                          // mean
-            0.0016,                          // std dev
+            Some(0.0016),                    // std dev
             0.1057,                          // median
             0.0009,                          // user_mean
             0.0011,                          // system_mean
diff --git a/src/main.rs b/src/main.rs
index 63c87bf..6db752a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -61,9 +61,13 @@ pub fn write_benchmark_comparison(results: &[BenchmarkResult]) {
 
         for item in others {
             println!(
-                "{} ± {} times faster than '{}'",
+                "{}{} times faster than '{}'",
                 format!("{:8.2}", item.relative_speed).bold().green(),
-                format!("{:.2}", item.relative_speed_stddev).green(),
+                if let Some(stddev) = item.relative_speed_stddev {
+                    format!(" ± {}", format!("{:.2}", stddev).green())
+                } else {
+                    "".into()
+                },
                 &item.result.command.magenta()
             );
         }
diff --git a/src/relative_speed.rs b/src/relative_speed.rs
index a87b8f5..093e3c5 100644
--- a/src/relative_speed.rs
+++ b/src/relative_speed.rs
@@ -6,7 +6,7 @@ use crate::{benchmark_result::BenchmarkResult, units::Scalar};
 pub struct BenchmarkResultWithRelativeSpeed<'a> {
     pub result: &'a BenchmarkResult,
     pub relative_speed: Scalar,
-    pub relative_speed_stddev: Scalar,
+    pub relative_speed_stddev: Option<Scalar>,
     pub is_fastest: bool,
 }
 
@@ -32,10 +32,15 @@ pub fn compute(results: &[BenchmarkResult]) -> Option<Vec<BenchmarkResultWithRel
 
                 // https://en.wikipedia.org/wiki/Propagation_of_uncertainty#Example_formulas
                 // Covariance asssumed to be 0, i.e. variables are assumed to be independent
-                let ratio_stddev = ratio
-                    * ((result.stddev / result.mean).powi(2)
-                        + (fastest.stddev / fastest.mean).powi(2))
-                    .sqrt();
+                let ratio_stddev = match (result.stddev, fastest.stddev) {
+                    (Some(result_stddev), Some(fastest_stddev)) => Some(
+                        ratio
+                            * ((result_stddev / result.mean).powi(2)
+                                + (fastest_stddev / fastest.mean).powi(2))
+                            .sqrt(),
+                    ),
+                    _ => None,
+                };
 
                 BenchmarkResultWithRelativeSpeed {
                     result,
@@ -55,7 +60,7 @@ fn create_result(name: &str, mean: Scalar) -> BenchmarkResult {
     BenchmarkResult {
         command: name.into(),
         mean,
-        stddev: 1.0,
+        stddev: Some(1.0),
         median: mean,
         user: mean,
         system: 0.0,