diff --git a/src/unit.rs b/src/unit.rs
new file mode 100644
index 0000000..a1393f8
--- /dev/null
+++ b/src/unit.rs
@@ -0,0 +1,84 @@
+use std::fmt::Display;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Unit {
+    Byte,
+
+    Kilo,
+    Kibi,
+
+    Mega,
+    Mibi,
+
+    Giga,
+    Gibi,
+
+    Tera,
+    Tibi,
+}
+impl Unit {
+    pub fn parse(s: &str) -> Result<Self, String> {
+        let s = s.to_lowercase();
+        match s.as_str() {
+            "b" => Ok(Self::Byte),
+            "k" | "kb" => Ok(Self::Kilo),
+            "ki" => Ok(Self::Kibi),
+            "m" | "mb" => Ok(Self::Mega),
+            "mi" => Ok(Self::Mibi),
+            "g" | "gb" => Ok(Self::Giga),
+            "gi" => Ok(Self::Gibi),
+            "t" | "tb" => Ok(Self::Tera),
+            "ti" => Ok(Self::Tibi),
+            _ => Err(s),
+        }
+    }
+
+    pub fn convert(self, n: u64) -> String {
+        format!("{}{}", n/self.integer_value(), self.units_pretty())
+    }
+
+    const fn units_pretty(self) -> &'static str {
+        match self {
+            Self::Byte => "",
+            Self::Kilo => " K",
+            Self::Kibi => " Ki",
+            Self::Mega => " M",
+            Self::Mibi => " Mi",
+            Self::Giga => " G",
+            Self::Gibi => " Gi",
+            Self::Tera => " T",
+            Self::Tibi => " Ti",
+        }
+    }
+
+    const fn integer_value(self) -> u64 {
+        match self {
+            Self::Byte => 1,
+            Self::Kilo => 1_000,
+            Self::Kibi => 1_024,
+            Self::Mega => 1_000_000,
+            Self::Mibi => 1_048_576,
+            Self::Giga => 1_000_000_000,
+            Self::Gibi => 1_073_741_824,
+            Self::Tera => 1_000_000_000_000,
+            Self::Tibi => 1_099_511_627_776,
+        }
+    }
+}
+impl Display for Unit {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let s = match self {
+            Self::Byte => "b",
+            Self::Kilo => "K",
+            Self::Kibi => "Ki",
+            Self::Mega => "M",
+            Self::Mibi => "Mi",
+            Self::Giga => "G",
+            Self::Gibi => "Gi",
+            Self::Tera => "T",
+            Self::Tibi => "Ti",
+        };
+
+        f.write_str(s)
+    }
+}