diff --git a/src/diagram_formatting.rs b/src/diagram_formatting.rs
index 53b7e7d..b6de767 100644
--- a/src/diagram_formatting.rs
+++ b/src/diagram_formatting.rs
@@ -2,6 +2,12 @@ use super::file_tree::{File, FileTree, FileType};
 use std::collections::HashMap;
 use std::fs;
 
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Charset {
+    Unicode,
+    Ascii,
+}
+
 #[derive(Debug, Clone, PartialEq)]
 enum PrefixSegment {
     ShapeL, // "└── "
@@ -10,6 +16,25 @@ enum PrefixSegment {
     Empty,  // "    "
 }
 
+impl PrefixSegment {
+    fn as_str(&self, charset: Charset) -> &'static str {
+        match charset {
+            Charset::Unicode => match self {
+                PrefixSegment::ShapeL => "└── ",
+                PrefixSegment::ShapeT => "├── ",
+                PrefixSegment::ShapeI => "│   ",
+                PrefixSegment::Empty => "    ",
+            },
+            Charset::Ascii => match self {
+                PrefixSegment::ShapeL => "\\-- ",
+                PrefixSegment::ShapeT => "|-- ",
+                PrefixSegment::ShapeI => "|   ",
+                PrefixSegment::Empty => "    ",
+            },
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq)]
 pub struct FormattedEntry {
     pub name: String,
@@ -18,7 +43,12 @@ pub struct FormattedEntry {
     pub link: Option<String>,
 }
 
-fn make_prefix(tree: &FileTree, file: &File, format_history: &HashMap<usize, usize>) -> String {
+fn make_prefix(
+    tree: &FileTree,
+    file: &File,
+    format_history: &HashMap<usize, usize>,
+    charset: Charset,
+) -> String {
     let mut segments = Vec::new();
     let mut current = file;
     if let Some(ancestor) = tree.get_parent(file) {
@@ -42,14 +72,9 @@ fn make_prefix(tree: &FileTree, file: &File, format_history: &HashMap<usize, usi
     }
 
     segments.reverse();
-    segments.iter().fold(String::new(), |s, seg| {
-        s + match seg {
-            PrefixSegment::ShapeL => "└── ",
-            PrefixSegment::ShapeT => "├── ",
-            PrefixSegment::ShapeI => "│   ",
-            PrefixSegment::Empty => "    ",
-        }
-    })
+    segments
+        .iter()
+        .fold(String::new(), |s, seg| s + seg.as_str(charset))
 }
 
 fn format_file(
@@ -58,8 +83,9 @@ fn format_file(
     format_history: &mut HashMap<usize, usize>,
     result: &mut Vec<FormattedEntry>,
     make_absolute: bool,
+    charset: Charset,
 ) {
-    let prefix = make_prefix(tree, file, format_history);
+    let prefix = make_prefix(tree, file, format_history, charset);
     let path = if make_absolute {
         fs::canonicalize(&file.path).unwrap().display().to_string()
     } else {
@@ -91,6 +117,7 @@ fn format_file(
                 format_history,
                 result,
                 make_absolute,
+                charset,
             );
         }
     }
@@ -100,13 +127,21 @@ pub fn format_paths(
     root_path: &str,
     children: Vec<(String, FileType)>,
     make_absolute: bool,
+    charset: Charset,
 ) -> Vec<FormattedEntry> {
     let mut history = HashMap::new();
     let mut result = Vec::new();
     match FileTree::new(root_path, children) {
         Some(tree) => {
             let root = tree.get_root();
-            format_file(&tree, root, &mut history, &mut result, make_absolute);
+            format_file(
+                &tree,
+                root,
+                &mut history,
+                &mut result,
+                make_absolute,
+                charset,
+            );
             result
         }
         None => Vec::new(),
@@ -115,20 +150,20 @@ pub fn format_paths(
 
 #[cfg(test)]
 mod test {
-    use super::FormattedEntry;
+    use super::{Charset, FormattedEntry};
     use crate::file_tree::FileType;
     use std::path;
 
+    fn test_input() -> Vec<(String, FileType)> {
+        vec![
+            ("a".to_string(), FileType::File),
+            (format!("b{}c", path::MAIN_SEPARATOR), FileType::File),
+        ]
+    }
+
     #[test]
     fn formatting_works() {
-        let formatted = super::format_paths(
-            ".",
-            vec![
-                ("a".to_string(), FileType::File),
-                (format!("b{}c", path::MAIN_SEPARATOR), FileType::File),
-            ],
-            false,
-        );
+        let formatted = super::format_paths(".", test_input(), false, Charset::Unicode);
 
         let bc_path = format!("b{}c", path::MAIN_SEPARATOR);
         let b_path = format!(".{}b", path::MAIN_SEPARATOR);
@@ -188,4 +223,67 @@ mod test {
 
         assert!(formatted == variant0 || formatted == variant1);
     }
+
+    #[test]
+    fn formatting_ascii() {
+        let formatted = super::format_paths(".", test_input(), false, Charset::Ascii);
+
+        let bc_path = format!("b{}c", path::MAIN_SEPARATOR);
+        let b_path = format!(".{}b", path::MAIN_SEPARATOR);
+        let variant0 = vec![
+            FormattedEntry {
+                name: ".".to_string(),
+                path: ".".to_string(),
+                prefix: String::new(),
+                link: None,
+            },
+            FormattedEntry {
+                name: "a".to_string(),
+                path: "a".to_string(),
+                prefix: "|-- ".to_string(),
+                link: None,
+            },
+            FormattedEntry {
+                name: "b".to_string(),
+                path: b_path.clone(),
+                prefix: "`-- ".to_string(),
+                link: None,
+            },
+            FormattedEntry {
+                name: "c".to_string(),
+                path: bc_path.clone(),
+                prefix: "    `-- ".to_string(),
+                link: None,
+            },
+        ];
+
+        let variant1 = vec![
+            FormattedEntry {
+                name: ".".to_string(),
+                path: ".".to_string(),
+                prefix: String::new(),
+                link: None,
+            },
+            FormattedEntry {
+                name: "b".to_string(),
+                path: b_path.clone(),
+                prefix: "|-- ".to_string(),
+                link: None,
+            },
+            FormattedEntry {
+                name: "c".to_string(),
+                path: bc_path.clone(),
+                prefix: "|   `-- ".to_string(),
+                link: None,
+            },
+            FormattedEntry {
+                name: "a".to_string(),
+                path: "a".to_string(),
+                prefix: "`-- ".to_string(),
+                link: None,
+            },
+        ];
+
+        assert!(formatted == variant0 || formatted == variant1);
+    }
 }
diff --git a/src/tre.rs b/src/tre.rs
index 6295fd5..f87b142 100644
--- a/src/tre.rs
+++ b/src/tre.rs
@@ -99,14 +99,20 @@ pub fn run(option: RunOptions) {
     if option.output_json {
         println!("{}", json_formatting::format_paths(&option.root, paths));
     } else {
+        let is_tty = atty::is(atty::Stream::Stdout);
+        let charset = if cfg!(windows) && !is_tty {
+            diagram_formatting::Charset::Ascii
+        } else {
+            diagram_formatting::Charset::Unicode
+        };
         let format_result =
-            diagram_formatting::format_paths(&option.root, paths, option.portable_aliases);
+            diagram_formatting::format_paths(&option.root, paths, option.portable_aliases, charset);
         let lscolors = LsColors::from_env().unwrap_or_default();
         let coloring = match option.coloring {
             cli::Coloring::Never => None,
             cli::Coloring::Always => Some(&lscolors),
             cli::Coloring::Automatic => {
-                if atty::is(atty::Stream::Stdout) {
+                if is_tty {
                     Some(&lscolors)
                 } else {
                     None
diff --git a/tests/integration_tests.rs b/tests/integration_tests.rs
index 77489f6..b86b22f 100644
--- a/tests/integration_tests.rs
+++ b/tests/integration_tests.rs
@@ -6,6 +6,17 @@ use std::str;
 use assert_cmd::prelude::CommandCargoExt;
 use std::env;
 
+// on Windows, piped output uses ascii for formatting instead of unicode.
+// this function makes the tests check for ascii formatting on Windows and
+// unicode formatting on other platforms
+fn has_entry(text: &str, name: &str) -> bool {
+    if cfg!(windows) {
+        text.contains(&format!("-- {}", name))
+    } else {
+        text.contains(&format!("── {}", name))
+    }
+}
+
 #[test]
 fn respect_git_ignore() -> Result<(), Box<dyn error::Error>> {
     let mut tre = process::Command::cargo_bin("tre")?;
@@ -24,15 +35,15 @@ fn respect_git_ignore() -> Result<(), Box<dyn error::Error>> {
     let output = tre.output()?.stdout;
     let text = str::from_utf8(&output)?;
     assert!(text.contains("."));
-    assert!(text.contains("── .gitignore"));
-    assert!(text.contains("── a"));
-    assert!(text.contains("── b"));
-    assert!(text.contains("── c"));
-    assert!(text.contains("── d"));
-    assert!(text.contains("── e"));
-    assert!(text.contains("── h"));
-    assert!(text.contains("── f"));
-    assert!(text.contains("── g"));
+    assert!(has_entry(text, ".gitignore"));
+    assert!(has_entry(text, "a"));
+    assert!(has_entry(text, "b"));
+    assert!(has_entry(text, "c"));
+    assert!(has_entry(text, "d"));
+    assert!(has_entry(text, "e"));
+    assert!(has_entry(text, "h"));
+    assert!(has_entry(text, "f"));
+    assert!(has_entry(text, "g"));
     assert!(!text.contains("ignore_me"));
     Ok(())
 }
@@ -56,15 +67,15 @@ fn ignore_hidden() -> Result<(), Box<dyn error::Error>> {
     let output = tre.arg("-s").output()?.stdout;
     let text = str::from_utf8(&output)?;
     assert!(text.contains("."));
-    assert!(!text.contains("── .gitignore")); // hidden files should be hidden
-    assert!(text.contains("── a"));
-    assert!(text.contains("── b"));
-    assert!(text.contains("── c"));
-    assert!(text.contains("── d"));
-    assert!(text.contains("── e"));
-    assert!(text.contains("── h"));
-    assert!(text.contains("── f"));
-    assert!(text.contains("── g"));
+    assert!(!has_entry(text, ".gitignore")); // hidden files should be hidden
+    assert!(has_entry(text, "a"));
+    assert!(has_entry(text, "b"));
+    assert!(has_entry(text, "c"));
+    assert!(has_entry(text, "d"));
+    assert!(has_entry(text, "e"));
+    assert!(has_entry(text, "h"));
+    assert!(has_entry(text, "f"));
+    assert!(has_entry(text, "g"));
     assert!(text.contains("ignore_me"));
     Ok(())
 }
@@ -87,15 +98,15 @@ fn all_files() -> Result<(), Box<dyn error::Error>> {
     let output = tre.arg("-a").output()?.stdout;
     let text = str::from_utf8(&output)?;
     assert!(text.contains("."));
-    assert!(text.contains("── .gitignore")); // hidden files should be hidden
-    assert!(text.contains("── a"));
-    assert!(text.contains("── b"));
-    assert!(text.contains("── c"));
-    assert!(text.contains("── d"));
-    assert!(text.contains("── e"));
-    assert!(text.contains("── h"));
-    assert!(text.contains("── f"));
-    assert!(text.contains("── g"));
+    assert!(has_entry(text, ".gitignore"));
+    assert!(has_entry(text, "a"));
+    assert!(has_entry(text, "b"));
+    assert!(has_entry(text, "c"));
+    assert!(has_entry(text, "d"));
+    assert!(has_entry(text, "e"));
+    assert!(has_entry(text, "h"));
+    assert!(has_entry(text, "f"));
+    assert!(has_entry(text, "g"));
     assert!(text.contains("ignore_me"));
     Ok(())
 }