diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d0e764e..67c70f2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -82,18 +82,43 @@ jobs:
         run: cargo x test --no-capture
         shell: bash
 
+  no_std:
+    name: Check no_std
+    needs: msrv
+    strategy:
+      matrix:
+        rust-version: ${{ fromJson(needs.msrv.outputs.rust-versions) }}
+    runs-on: ubuntu-24.04
+    steps:
+      - uses: actions/checkout@v6
+      - uses: Swatinem/rust-cache@v2
+      - name: Delete rust-toolchain.toml
+        run: rm rust-toolchain.toml
+      - name: Install toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: ${{ matrix.rust-version }}
+          targets: thumbv7em-none-eabihf
+      - name: Check no_std
+        run: |
+          cargo check -p bsize --no-default-features --target thumbv7em-none-eabihf
+          cargo check -p bsize --all-features --target thumbv7em-none-eabihf
+        shell: bash
+
   required:
     name: Required
     runs-on: ubuntu-24.04
     if: ${{ always() }}
     needs:
       - check
+      - no_std
       - test
     steps:
       - name: Guardian
         run: |
           if [[ ! ( \
                  "${{ needs.check.result }}" == "success" \
+              && "${{ needs.no_std.result }}" == "success" \
               && "${{ needs.test.result }}" == "success" \
               ) ]]; then
             echo "Required jobs haven't been completed successfully."
diff --git a/bsize/Cargo.toml b/bsize/Cargo.toml
index 888e9f7..53236da 100644
--- a/bsize/Cargo.toml
+++ b/bsize/Cargo.toml
@@ -37,7 +37,7 @@ default = []
 serde = ["dep:serde_core"]
 
 [dependencies]
-serde_core = { version = "1", optional = true }
+serde_core = { version = "1", default-features = false, optional = true }
 
 [dev-dependencies]
 serde = { version = "1", features = ["derive"] }
diff --git a/bsize/src/parse.rs b/bsize/src/parse.rs
index 6f95bd9..c47a2b5 100644
--- a/bsize/src/parse.rs
+++ b/bsize/src/parse.rs
@@ -149,7 +149,7 @@ fn parse_size(mut src: &[u8]) -> Result<u64, ParseError> {
                     state = ParseState::Integer;
                 } else {
                     if *b >= b'5' {
-                        mantissa += 1;
+                        mantissa = mantissa.checked_add(1).ok_or(ParseError::Overflow)?;
                     }
                     state = ParseState::IntegerOverflow;
                     exponent += 1;
@@ -164,7 +164,7 @@ fn parse_size(mut src: &[u8]) -> Result<u64, ParseError> {
                     exponent -= 1;
                 } else {
                     if *b >= b'5' {
-                        mantissa += 1;
+                        mantissa = mantissa.checked_add(1).ok_or(ParseError::Overflow)?;
                     }
                     state = ParseState::FractionOverflow;
                 }
@@ -307,6 +307,8 @@ mod tests {
         for input in [
             "18_446_744_073_709_551_616",
             "18_446_744_073_709_551_620",
+            "18446744073709551615.5",
+            "184467440737095516155",
             "18.446_744_073_709_551_616 EB",
             "19EB",
             "16EiB",
diff --git a/bsize/src/serde.rs b/bsize/src/serde.rs
index 1034c3c..bccc4c7 100644
--- a/bsize/src/serde.rs
+++ b/bsize/src/serde.rs
@@ -40,7 +40,7 @@ macro_rules! impl_serialize {
 impl_serialize!(u8, u16, u32, u64, usize);
 
 macro_rules! impl_deserialize {
-    ($($ty:ty),* $(,)?) => {
+    ($($ty:ty => $deserialize:ident),* $(,)?) => {
         $(
             impl<'de> serde_core::Deserialize<'de> for BSize<$ty> {
                 fn deserialize<D>(de: D) -> Result<Self, D::Error>
@@ -100,7 +100,7 @@ macro_rules! impl_deserialize {
                     if de.is_human_readable() {
                         de.deserialize_any(Visitor)
                     } else {
-                        de.deserialize_u64(Visitor)
+                        de.$deserialize(Visitor)
                     }
                 }
             }
@@ -108,7 +108,18 @@ macro_rules! impl_deserialize {
     };
 }
 
-impl_deserialize!(u8, u16, u32, u64, usize);
+impl_deserialize!(
+    u8 => deserialize_u8,
+    u16 => deserialize_u16,
+    u32 => deserialize_u32,
+    u64 => deserialize_u64,
+);
+
+#[cfg(target_pointer_width = "32")]
+impl_deserialize!(usize => deserialize_u32);
+
+#[cfg(target_pointer_width = "64")]
+impl_deserialize!(usize => deserialize_u64);
 
 #[cfg(test)]
 mod tests {
diff --git a/taplo.toml b/taplo.toml
index 1cb0f3a..ebbb309 100644
--- a/taplo.toml
+++ b/taplo.toml
@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+exclude = ["target/**"]
 include = ["Cargo.toml", "**/*.toml"]
 
 [formatting]
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 94004b9..937be94 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! An xtask binary for managing workspace tasks.
+//! A binary for managing workspace tasks.
 
 use std::path::Path;
 use std::process::Command as StdCommand;
@@ -71,6 +71,7 @@ struct CommandTest {
 impl CommandTest {
     fn run(self) {
         run_command(make_test_cmd(self.no_capture, &[]));
+        run_command(make_test_cmd(self.no_capture, &["serde"]));
     }
 }