diff --git a/bitcoin/src/crypto/sighash.rs b/bitcoin/src/crypto/sighash.rs
index 4b85e1b1..16806d56 100644
--- a/bitcoin/src/crypto/sighash.rs
+++ b/bitcoin/src/crypto/sighash.rs
@@ -48,12 +48,12 @@ macro_rules! impl_thirty_two_byte_hash {
 }
 
 #[rustfmt::skip]
-hash_newtype!(LegacySighash, sha256d::Hash, 32,
+hash_newtype!(LegacySighash, sha256d::Hash,
     doc="Hash of a transaction according to the legacy signature algorithm", false);
 impl_thirty_two_byte_hash!(LegacySighash);
 
 #[rustfmt::skip]
-hash_newtype!(SegwitV0Sighash, sha256d::Hash, 32,
+hash_newtype!(SegwitV0Sighash, sha256d::Hash,
     doc="Hash of a transaction according to the segwit version 0 signature algorithm", false);
 impl_thirty_two_byte_hash!(SegwitV0Sighash);
 
diff --git a/bitcoin/src/hash_types.rs b/bitcoin/src/hash_types.rs
index 31b7cb84..04a4478f 100644
--- a/bitcoin/src/hash_types.rs
+++ b/bitcoin/src/hash_types.rs
@@ -56,7 +56,7 @@ mod newtypes {
     use crate::hashes::{sha256, sha256d, hash160, hash_newtype};
 
     hash_newtype!(
-        Txid, sha256d::Hash, 32, doc="A bitcoin transaction hash/transaction ID.
+        Txid, sha256d::Hash, doc="A bitcoin transaction hash/transaction ID.
 
 For compatibility with the existing Bitcoin infrastructure and historical
 and current versions of the Bitcoin Core software itself, this and
@@ -64,21 +64,21 @@ other [`sha256d::Hash`] types, are serialized in reverse
 byte order when converted to a hex string via [`std::fmt::Display`] trait operations.
 See [`hashes::Hash::DISPLAY_BACKWARD`] for more details.
 ");
-    hash_newtype!(Wtxid, sha256d::Hash, 32, doc="A bitcoin witness transaction ID.");
-    hash_newtype!(BlockHash, sha256d::Hash, 32, doc="A bitcoin block hash.");
+    hash_newtype!(Wtxid, sha256d::Hash, doc="A bitcoin witness transaction ID.");
+    hash_newtype!(BlockHash, sha256d::Hash, doc="A bitcoin block hash.");
 
-    hash_newtype!(PubkeyHash, hash160::Hash, 20, doc="A hash of a public key.");
-    hash_newtype!(ScriptHash, hash160::Hash, 20, doc="A hash of Bitcoin Script bytecode.");
-    hash_newtype!(WPubkeyHash, hash160::Hash, 20, doc="SegWit version of a public key hash.");
-    hash_newtype!(WScriptHash, sha256::Hash, 32, doc="SegWit version of a Bitcoin Script bytecode hash.");
+    hash_newtype!(PubkeyHash, hash160::Hash, doc="A hash of a public key.");
+    hash_newtype!(ScriptHash, hash160::Hash, doc="A hash of Bitcoin Script bytecode.");
+    hash_newtype!(WPubkeyHash, hash160::Hash, doc="SegWit version of a public key hash.");
+    hash_newtype!(WScriptHash, sha256::Hash, doc="SegWit version of a Bitcoin Script bytecode hash.");
 
-    hash_newtype!(TxMerkleNode, sha256d::Hash, 32, doc="A hash of the Merkle tree branch or root for transactions");
-    hash_newtype!(WitnessMerkleNode, sha256d::Hash, 32, doc="A hash corresponding to the Merkle tree root for witness data");
-    hash_newtype!(WitnessCommitment, sha256d::Hash, 32, doc="A hash corresponding to the witness structure commitment in the coinbase transaction");
-    hash_newtype!(XpubIdentifier, hash160::Hash, 20, doc="XpubIdentifier as defined in BIP-32.");
+    hash_newtype!(TxMerkleNode, sha256d::Hash, doc="A hash of the Merkle tree branch or root for transactions");
+    hash_newtype!(WitnessMerkleNode, sha256d::Hash, doc="A hash corresponding to the Merkle tree root for witness data");
+    hash_newtype!(WitnessCommitment, sha256d::Hash, doc="A hash corresponding to the witness structure commitment in the coinbase transaction");
+    hash_newtype!(XpubIdentifier, hash160::Hash, doc="XpubIdentifier as defined in BIP-32.");
 
-    hash_newtype!(FilterHash, sha256d::Hash, 32, doc="Filter hash, as defined in BIP-157");
-    hash_newtype!(FilterHeader, sha256d::Hash, 32, doc="Filter header, as defined in BIP-157");
+    hash_newtype!(FilterHash, sha256d::Hash, doc="Filter hash, as defined in BIP-157");
+    hash_newtype!(FilterHeader, sha256d::Hash, doc="Filter header, as defined in BIP-157");
 
     impl_hashencode!(Txid);
     impl_hashencode!(Wtxid);
diff --git a/hashes/embedded/src/main.rs b/hashes/embedded/src/main.rs
index 22773ad2..ed36fc52 100644
--- a/hashes/embedded/src/main.rs
+++ b/hashes/embedded/src/main.rs
@@ -18,7 +18,7 @@ use cortex_m_rt::entry;
 use cortex_m_semihosting::{debug, hprintln};
 use panic_halt as _;
 
-hash_newtype!(TestType, sha256::Hash, 32, doc = "test");
+hash_newtype!(TestType, sha256::Hash, doc = "test");
 
 // this is the allocator the application will use
 #[cfg(feature = "alloc")]
diff --git a/hashes/src/lib.rs b/hashes/src/lib.rs
index 66b3a75d..315bb4c0 100644
--- a/hashes/src/lib.rs
+++ b/hashes/src/lib.rs
@@ -220,8 +220,8 @@ pub trait Hash: Copy + Clone + PartialEq + Eq + PartialOrd + Ord +
 mod tests {
     use crate::{Hash, sha256d};
 
-    hash_newtype!(TestNewtype, sha256d::Hash, 32, doc="A test newtype");
-    hash_newtype!(TestNewtype2, sha256d::Hash, 32, doc="A test newtype");
+    hash_newtype!(TestNewtype, sha256d::Hash, doc="A test newtype");
+    hash_newtype!(TestNewtype2, sha256d::Hash, doc="A test newtype");
 
     #[test]
     fn convert_newtypes() {
diff --git a/hashes/src/sha256t.rs b/hashes/src/sha256t.rs
index e52e0ae0..ec0991ff 100644
--- a/hashes/src/sha256t.rs
+++ b/hashes/src/sha256t.rs
@@ -115,7 +115,7 @@ macro_rules! sha256t_hash_newtype {
             }
         }
 
-        $crate::hash_newtype!($newtype, $crate::sha256t::Hash<$tag>, 32, $docs, $reverse);
+        $crate::hash_newtype!($newtype, $crate::sha256t::Hash<$tag>, $docs, $reverse);
     };
 }
 
diff --git a/hashes/src/util.rs b/hashes/src/util.rs
index d9354d1a..f992c7ab 100644
--- a/hashes/src/util.rs
+++ b/hashes/src/util.rs
@@ -112,10 +112,10 @@ macro_rules! engine_input_impl(
 /// Creates a new newtype around a [`Hash`] type.
 #[macro_export]
 macro_rules! hash_newtype {
-    ($newtype:ident, $hash:ty, $len:expr, $docs:meta) => {
-        $crate::hash_newtype!($newtype, $hash, $len, $docs, <$hash as $crate::Hash>::DISPLAY_BACKWARD);
+    ($newtype:ident, $hash:ty, $docs:meta) => {
+        $crate::hash_newtype!($newtype, $hash, $docs, <$hash as $crate::Hash>::DISPLAY_BACKWARD);
     };
-    ($newtype:ident, $hash:ty, $len:expr, $docs:meta, $reverse:expr) => {
+    ($newtype:ident, $hash:ty, $docs:meta, $reverse:expr) => {
         #[$docs]
         #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
         #[repr(transparent)]
@@ -276,7 +276,7 @@ mod test {
         assert_eq!(borrowed, hash.as_inner());
     }
 
-    hash_newtype!(TestHash, crate::sha256d::Hash, 32, doc="Test hash.");
+    hash_newtype!(TestHash, crate::sha256d::Hash, doc="Test hash.");
 
     #[test]
     fn display() {