diff --git a/api/bin/chainflip-broker-api/src/main.rs b/api/bin/chainflip-broker-api/src/main.rs
index 07f89a109d..5f20e9e0f5 100644
--- a/api/bin/chainflip-broker-api/src/main.rs
+++ b/api/bin/chainflip-broker-api/src/main.rs
@@ -1,4 +1,5 @@
 use cf_utilities::{
+	rpc::NumberOrHex,
 	task_scope::{task_scope, Scope},
 	AnyhowRpcError,
 };
@@ -12,7 +13,6 @@ use clap::Parser;
 use futures::FutureExt;
 use jsonrpsee::{core::async_trait, proc_macros::rpc, server::ServerBuilder};
 use serde::{Deserialize, Serialize};
-use sp_rpc::number::NumberOrHex;
 use std::path::PathBuf;
 use tracing::log;
 
diff --git a/api/bin/chainflip-lp-api/src/main.rs b/api/bin/chainflip-lp-api/src/main.rs
index bd3e859dd8..70a79eb1fe 100644
--- a/api/bin/chainflip-lp-api/src/main.rs
+++ b/api/bin/chainflip-lp-api/src/main.rs
@@ -1,4 +1,5 @@
 use cf_utilities::{
+	rpc::NumberOrHex,
 	task_scope::{task_scope, Scope},
 	try_parse_number_or_hex, AnyhowRpcError,
 };
@@ -17,7 +18,6 @@ use futures::FutureExt;
 use jsonrpsee::{core::async_trait, proc_macros::rpc, server::ServerBuilder};
 use pallet_cf_pools::{IncreaseOrDecrease, OrderId, RangeOrderSize};
 use rpc_types::{OpenSwapChannels, OrderIdJson, RangeOrderSizeJson};
-use sp_rpc::number::NumberOrHex;
 use std::{collections::BTreeMap, ops::Range, path::PathBuf};
 use tracing::log;
 
@@ -25,10 +25,10 @@ use tracing::log;
 pub mod rpc_types {
 	use super::*;
 	use anyhow::anyhow;
+	use cf_utilities::rpc::NumberOrHex;
 	use chainflip_api::queries::SwapChannelInfo;
 	use pallet_cf_pools::AssetsMap;
 	use serde::{Deserialize, Serialize};
-	use sp_rpc::number::NumberOrHex;
 
 	#[derive(Copy, Clone, Debug, Serialize, Deserialize)]
 	pub struct OrderIdJson(NumberOrHex);
diff --git a/state-chain/custom-rpc/src/lib.rs b/state-chain/custom-rpc/src/lib.rs
index 77a2076837..0ed7c25159 100644
--- a/state-chain/custom-rpc/src/lib.rs
+++ b/state-chain/custom-rpc/src/lib.rs
@@ -730,13 +730,16 @@ where
 				self.unwrap_or_best(at),
 				from,
 				to,
-				amount.try_into().and_then(|amount| {
-					if amount == 0 {
-						Err(anyhow::anyhow!("Swap input amount cannot be zero."))
-					} else {
-						Ok(amount)
-					}
-				})?,
+				amount
+					.try_into()
+					.and_then(|amount| {
+						if amount == 0 {
+							Err("Swap input amount cannot be zero.")
+						} else {
+							Ok(amount)
+						}
+					})
+					.map_err(|str| anyhow::anyhow!(str))?,
 			)
 			.map_err(to_rpc_error)
 			.and_then(|r| {
diff --git a/utilities/src/with_std.rs b/utilities/src/with_std.rs
index ef51b74e11..b9c65e0981 100644
--- a/utilities/src/with_std.rs
+++ b/utilities/src/with_std.rs
@@ -4,7 +4,7 @@ use futures::{stream, Stream};
 use jsonrpsee::types::{error::CALL_EXECUTION_FAILED_CODE, ErrorObjectOwned};
 #[doc(hidden)]
 pub use lazy_format::lazy_format as internal_lazy_format;
-use sp_rpc::number::NumberOrHex;
+use rpc::NumberOrHex;
 
 pub mod future_map;
 pub mod loop_select;
@@ -54,7 +54,7 @@ pub fn clean_hex_address<A: TryFrom<Vec<u8>>>(address_str: &str) -> Result<A, an
 
 pub fn try_parse_number_or_hex(amount: NumberOrHex) -> anyhow::Result<u128> {
 	u128::try_from(amount).map_err(|_| {
-		anyhow!("Error parsing amount. Please use a valid number or hex string as input.")
+		anyhow!("Error parsing amount to u128. Please use a valid number or hex string as input.")
 	})
 }
 
diff --git a/utilities/src/with_std/rpc.rs b/utilities/src/with_std/rpc.rs
index 57ae093aee..a415b6e995 100644
--- a/utilities/src/with_std/rpc.rs
+++ b/utilities/src/with_std/rpc.rs
@@ -1,8 +1,7 @@
-use anyhow::anyhow;
 use serde::{Deserialize, Serialize};
 use sp_core::U256;
 
-#[derive(Debug, PartialEq, Eq, Deserialize)]
+#[derive(Debug, PartialEq, Eq, Deserialize, Copy, Clone)]
 #[serde(untagged)]
 pub enum NumberOrHex {
 	Number(u64),
@@ -51,15 +50,24 @@ macro_rules! impl_safe_hex {
 
 impl_safe_hex!(u128, U256);
 
-impl TryInto<u128> for NumberOrHex {
-	type Error = anyhow::Error;
+impl TryFrom<NumberOrHex> for u128 {
+	type Error = &'static str;
 
-	fn try_into(self) -> Result<u128, Self::Error> {
-		match self {
-			Self::Number(n) => Ok(n.into()),
-			Self::Hex(n) => n.try_into().map_err(|_| {
-				anyhow!("Error parsing amount. Please use a valid number or hex string as input.")
-			}),
+	fn try_from(value: NumberOrHex) -> Result<Self, Self::Error> {
+		match value {
+			NumberOrHex::Number(n) => Ok(n.into()),
+			NumberOrHex::Hex(n) => u128::try_from(n),
+		}
+	}
+}
+
+impl TryFrom<NumberOrHex> for u64 {
+	type Error = &'static str;
+
+	fn try_from(value: NumberOrHex) -> Result<Self, Self::Error> {
+		match value {
+			NumberOrHex::Number(n) => Ok(n),
+			NumberOrHex::Hex(n) => u64::try_from(n),
 		}
 	}
 }
@@ -88,4 +96,17 @@ mod test {
 		assert_deser(r#"0"#, NumberOrHex::Number(0));
 		assert_deser(r#"1000000000000"#, NumberOrHex::Number(1000000000000));
 	}
+
+	#[test]
+	fn test_conversions() {
+		assert_eq!(u128::try_from(NumberOrHex::Hex(u128::MAX.into())).unwrap(), u128::MAX);
+		assert!(u128::try_from(NumberOrHex::Hex(U256::MAX / 2)).is_err());
+
+		assert_eq!(u64::try_from(NumberOrHex::Hex(u64::MAX.into())).unwrap(), u64::MAX);
+		assert_eq!(u64::try_from(NumberOrHex::Number(u64::MAX)).unwrap(), u64::MAX);
+		assert!(u64::try_from(NumberOrHex::Hex((u128::MAX / 2).into())).is_err());
+
+		assert_eq!(u128::try_from(NumberOrHex::Number(0)).unwrap(), 0);
+		assert_eq!(u128::try_from(NumberOrHex::Hex(U256::zero())).unwrap(), 0);
+	}
 }
diff --git a/utilities/src/with_std/serde_helpers/number_or_hex.rs b/utilities/src/with_std/serde_helpers/number_or_hex.rs
index 3c20486d33..9253f132ef 100644
--- a/utilities/src/with_std/serde_helpers/number_or_hex.rs
+++ b/utilities/src/with_std/serde_helpers/number_or_hex.rs
@@ -12,8 +12,8 @@
 //!     bar: u128,
 //! }
 /// ```
+use crate::rpc::NumberOrHex;
 use serde::{de::Error, Deserialize, Deserializer, Serialize, Serializer};
-use sp_rpc::number::NumberOrHex;
 
 pub fn serialize<S, T>(value: &T, serializer: S) -> Result<S::Ok, S::Error>
 where