diff --git a/ethers-core/src/utils/units.rs b/ethers-core/src/utils/units.rs
index 629908b2..82c55476 100644
--- a/ethers-core/src/utils/units.rs
+++ b/ethers-core/src/utils/units.rs
@@ -6,8 +6,16 @@ use std::{convert::TryFrom, fmt, str::FromStr};
 pub enum Units {
     /// Wei is equivalent to 1 wei.
     Wei,
+    /// Kwei is equivalent to 1e3 wei.
+    Kwei,
+    /// Mwei is equivalent to 1e6 wei.
+    Mwei,
     /// Gwei is equivalent to 1e9 wei.
     Gwei,
+    /// Twei is equivalent to 1e12 wei.
+    Twei,
+    /// Pwei is equivalent to 1e15 wei.
+    Pwei,
     /// Ether is equivalent to 1e18 wei.
     Ether,
     /// Other less frequent unit sizes, equivalent to 1e{0} wei.
@@ -74,7 +82,11 @@ impl FromStr for Units {
     fn from_str(s: &str) -> Result<Self, Self::Err> {
         Ok(match s.to_lowercase().as_str() {
             "eth" | "ether" => Units::Ether,
-            "gwei" | "nano" | "nanoether" => Units::Gwei,
+            "pwei" | "milli" | "milliether" | "finney" => Units::Pwei,
+            "twei" | "micro" | "microether" | "szabo" => Units::Twei,
+            "gwei" | "nano" | "nanoether" | "shannon" => Units::Gwei,
+            "mwei" | "pico" | "picoether" | "lovelace" => Units::Mwei,
+            "kwei" | "femto" | "femtoether" | "babbage" => Units::Kwei,
             "wei" => Units::Wei,
             _ => return Err(ConversionError::UnrecognizedUnits(s.to_string())),
         })
@@ -103,7 +115,11 @@ impl Units {
     pub fn as_num(&self) -> u32 {
         match self {
             Units::Wei => 0,
+            Units::Kwei => 3,
+            Units::Mwei => 6,
             Units::Gwei => 9,
+            Units::Twei => 12,
+            Units::Pwei => 15,
             Units::Ether => 18,
             Units::Other(inner) => *inner,
         }
@@ -118,7 +134,11 @@ mod tests {
     #[test]
     fn test_units() {
         assert_eq!(Wei.as_num(), 0);
+        assert_eq!(Kwei.as_num(), 3);
+        assert_eq!(Mwei.as_num(), 6);
         assert_eq!(Gwei.as_num(), 9);
+        assert_eq!(Twei.as_num(), 12);
+        assert_eq!(Pwei.as_num(), 15);
         assert_eq!(Ether.as_num(), 18);
         assert_eq!(Other(10).as_num(), 10);
         assert_eq!(Other(20).as_num(), 20);
@@ -127,15 +147,27 @@ mod tests {
     #[test]
     fn test_into() {
         assert_eq!(Units::try_from("wei").unwrap(), Wei);
+        assert_eq!(Units::try_from("kwei").unwrap(), Kwei);
+        assert_eq!(Units::try_from("mwei").unwrap(), Mwei);
         assert_eq!(Units::try_from("gwei").unwrap(), Gwei);
+        assert_eq!(Units::try_from("twei").unwrap(), Twei);
+        assert_eq!(Units::try_from("pwei").unwrap(), Pwei);
         assert_eq!(Units::try_from("ether").unwrap(), Ether);
 
         assert_eq!(Units::try_from("wei".to_string()).unwrap(), Wei);
+        assert_eq!(Units::try_from("kwei".to_string()).unwrap(), Kwei);
+        assert_eq!(Units::try_from("mwei".to_string()).unwrap(), Mwei);
         assert_eq!(Units::try_from("gwei".to_string()).unwrap(), Gwei);
+        assert_eq!(Units::try_from("twei".to_string()).unwrap(), Twei);
+        assert_eq!(Units::try_from("pwei".to_string()).unwrap(), Pwei);
         assert_eq!(Units::try_from("ether".to_string()).unwrap(), Ether);
 
         assert_eq!(Units::try_from(&"wei".to_string()).unwrap(), Wei);
+        assert_eq!(Units::try_from(&"kwei".to_string()).unwrap(), Kwei);
+        assert_eq!(Units::try_from(&"mwei".to_string()).unwrap(), Mwei);
         assert_eq!(Units::try_from(&"gwei".to_string()).unwrap(), Gwei);
+        assert_eq!(Units::try_from(&"twei".to_string()).unwrap(), Twei);
+        assert_eq!(Units::try_from(&"pwei".to_string()).unwrap(), Pwei);
         assert_eq!(Units::try_from(&"ether".to_string()).unwrap(), Ether);
     }
 }