diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 25931be2c..1c074f5f5 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -125,6 +125,12 @@ jobs:
       - name: Makefile tests
         run: cd temporal_capi/cpp_tests && make
 
+      # There's no guarantee that dependencies are no_std unless you test with a toolchain without `std`
+      - name: Install no_std toolchain
+        run: rustup target add thumbv7m-none-eabi
+      - name: Run no_std tests
+        run: cargo check -p temporal_capi --target thumbv7m-none-eabi
+
   docs:
     name: Documentation
     runs-on: ubuntu-latest
diff --git a/Cargo.lock b/Cargo.lock
index 6ebff0b67..c549648c6 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -893,6 +893,7 @@ name = "temporal_rs"
 version = "0.0.6"
 dependencies = [
  "combine",
+ "core_maths",
  "iana-time-zone",
  "icu_calendar",
  "ixdtf",
diff --git a/Cargo.toml b/Cargo.toml
index d0584121c..e5a1b001a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,7 +28,7 @@ temporal_provider = { version = "~0.0.6", path = "./provider" }
 tinystr = "0.8.1"
 icu_calendar = { version = "2.0.0-beta2", default-features = false }
 rustc-hash = "2.1.0"
-num-traits = "0.2.19"
+num-traits = { version = "0.2.19", default-features = false }
 ixdtf = "0.4.0"
 iana-time-zone = "0.1.63"
 log = "0.4.27"
@@ -71,6 +71,7 @@ combine = { workspace = true, optional = true }
 
 # System time feature
 web-time = { workspace = true, optional =  true }
+core_maths = "0.1.1"
 
 [features]
 default = ["sys"]
diff --git a/src/options/increment.rs b/src/options/increment.rs
index 571e1ba28..1fcc66e60 100644
--- a/src/options/increment.rs
+++ b/src/options/increment.rs
@@ -1,6 +1,7 @@
 use core::num::{NonZeroU128, NonZeroU32};
 
 use crate::{TemporalError, TemporalResult};
+use num_traits::float::FloatCore;
 
 // ==== RoundingIncrement option ====
 
@@ -31,7 +32,7 @@ impl TryFrom<f64> for RoundingIncrement {
         }
 
         // 5. Let integerIncrement be truncate(ℝ(increment)).
-        let integer_increment = value.trunc();
+        let integer_increment = FloatCore::trunc(value);
         // 6. If integerIncrement < 1 or integerIncrement > 10**9, throw a RangeError exception.
         if !(1.0..=1_000_000_000.0).contains(&integer_increment) {
             return Err(TemporalError::range()
diff --git a/src/primitive.rs b/src/primitive.rs
index 5e087e23f..2875acdc4 100644
--- a/src/primitive.rs
+++ b/src/primitive.rs
@@ -1,6 +1,7 @@
 //! Implementation of the FiniteF64 primitive
 
 use crate::{TemporalError, TemporalResult};
+use num_traits::float::FloatCore;
 use num_traits::{AsPrimitive, FromPrimitive, PrimInt};
 
 #[derive(Debug, Default, Clone, Copy, PartialEq, PartialOrd)]
@@ -48,7 +49,7 @@ impl FiniteF64 {
 
     #[inline]
     pub fn checked_mul_add(&self, a: FiniteF64, b: FiniteF64) -> TemporalResult<Self> {
-        let result = Self(self.0.mul_add(a.0, b.0));
+        let result = Self(core_maths::CoreFloat::mul_add(self.0, a.0, b.0));
         if !result.0.is_finite() {
             return Err(TemporalError::range().with_message("number value is not a finite value."));
         }
@@ -77,7 +78,7 @@ impl FiniteF64 {
     where
         f64: AsPrimitive<T>,
     {
-        if self.0 != self.0.trunc() {
+        if self.0 != FloatCore::trunc(self.0) {
             return Err(TemporalError::range().with_message("value must be integral."));
         }
         Ok(self.0.as_())
diff --git a/src/rounding.rs b/src/rounding.rs
index 55f60c36f..f46fcaaa0 100644
--- a/src/rounding.rs
+++ b/src/rounding.rs
@@ -11,6 +11,7 @@ use core::{
     ops::{Div, Neg},
 };
 
+use num_traits::float::FloatCore;
 use num_traits::{ConstZero, Euclid, FromPrimitive, NumCast, Signed, ToPrimitive};
 
 pub(crate) trait Roundable:
@@ -98,14 +99,16 @@ impl Roundable for f64 {
 
     fn compare_remainder(dividend: Self, divisor: Self) -> Option<Ordering> {
         let quotient = Roundable::quotient_abs(dividend, divisor);
-        let d1 = quotient - quotient.floor();
-        let d2 = quotient.ceil() - quotient;
+        let d1 = quotient - FloatCore::floor(quotient);
+        let d2 = FloatCore::ceil(quotient) - quotient;
         d1.partial_cmp(&d2)
     }
 
     fn is_even_cardinal(dividend: Self, divisor: Self) -> bool {
         let quotient = Roundable::quotient_abs(dividend, divisor);
-        (quotient.floor() / (quotient.ceil() - quotient.floor()) % 2.0) == 0.0
+        (FloatCore::floor(quotient) / (FloatCore::ceil(quotient) - FloatCore::floor(quotient))
+            % 2.0)
+            == 0.0
     }
 
     fn result_floor(dividend: Self, divisor: Self) -> u128 {
diff --git a/temporal_capi/src/calendar.rs b/temporal_capi/src/calendar.rs
index 014e6e7c7..db3f4ba31 100644
--- a/temporal_capi/src/calendar.rs
+++ b/temporal_capi/src/calendar.rs
@@ -9,8 +9,9 @@ pub mod ffi {
     use crate::plain_date::ffi::{PartialDate, PlainDate};
     use crate::plain_month_day::ffi::PlainMonthDay;
     use crate::plain_year_month::ffi::PlainYearMonth;
+    use alloc::boxed::Box;
+    use core::fmt::Write;
     use diplomat_runtime::DiplomatStr;
-    use std::fmt::Write;
 
     #[diplomat::enum_convert(icu_calendar::any_calendar::AnyCalendarKind, needs_wildcard)]
     pub enum AnyCalendarKind {
diff --git a/temporal_capi/src/duration.rs b/temporal_capi/src/duration.rs
index 999fcb17c..35b1faa8a 100644
--- a/temporal_capi/src/duration.rs
+++ b/temporal_capi/src/duration.rs
@@ -5,6 +5,7 @@ use crate::error::ffi::TemporalError;
 #[diplomat::attr(auto, namespace = "temporal_rs")]
 pub mod ffi {
     use crate::error::ffi::TemporalError;
+    use alloc::boxed::Box;
     use diplomat_runtime::DiplomatOption;
     use num_traits::FromPrimitive;
 
diff --git a/temporal_capi/src/error.rs b/temporal_capi/src/error.rs
index 29f8bc481..f385d459b 100644
--- a/temporal_capi/src/error.rs
+++ b/temporal_capi/src/error.rs
@@ -2,7 +2,6 @@
 #[diplomat::abi_rename = "temporal_rs_{0}"]
 #[diplomat::attr(auto, namespace = "temporal_rs")]
 pub mod ffi {
-
     #[diplomat::enum_convert(temporal_rs::error::ErrorKind)]
     pub enum ErrorKind {
         Generic,
diff --git a/temporal_capi/src/instant.rs b/temporal_capi/src/instant.rs
index f876951d5..3ad61fb7f 100644
--- a/temporal_capi/src/instant.rs
+++ b/temporal_capi/src/instant.rs
@@ -5,6 +5,7 @@ pub mod ffi {
     use crate::duration::ffi::{Duration, TimeDuration};
     use crate::error::ffi::TemporalError;
     use crate::options::ffi::{DifferenceSettings, RoundingOptions};
+    use alloc::boxed::Box;
 
     #[diplomat::opaque]
     pub struct Instant(pub temporal_rs::Instant);
diff --git a/temporal_capi/src/iso.rs b/temporal_capi/src/iso.rs
index fd690412b..e296b6630 100644
--- a/temporal_capi/src/iso.rs
+++ b/temporal_capi/src/iso.rs
@@ -4,7 +4,6 @@ use temporal_rs::iso;
 #[diplomat::abi_rename = "temporal_rs_{0}"]
 #[diplomat::attr(auto, namespace = "temporal_rs")]
 pub mod ffi {
-
     pub struct IsoDate {
         pub year: i32,
         pub month: u8,
diff --git a/temporal_capi/src/lib.rs b/temporal_capi/src/lib.rs
index 18254da4e..3f35abdaf 100644
--- a/temporal_capi/src/lib.rs
+++ b/temporal_capi/src/lib.rs
@@ -13,6 +13,10 @@
 //!
 //! [`temporal_rs`]: http://crates.io/crates/temporal_rs
 
+#![no_std]
+
+extern crate alloc;
+
 pub mod calendar;
 pub mod duration;
 pub mod error;
diff --git a/temporal_capi/src/plain_date.rs b/temporal_capi/src/plain_date.rs
index b50a5af4c..1d1261950 100644
--- a/temporal_capi/src/plain_date.rs
+++ b/temporal_capi/src/plain_date.rs
@@ -14,8 +14,9 @@ pub mod ffi {
     use crate::plain_month_day::ffi::PlainMonthDay;
     use crate::plain_time::ffi::PlainTime;
     use crate::plain_year_month::ffi::PlainYearMonth;
+    use alloc::boxed::Box;
+    use core::fmt::Write;
     use diplomat_runtime::{DiplomatOption, DiplomatStrSlice, DiplomatWrite};
-    use std::fmt::Write;
 
     #[diplomat::opaque]
     pub struct PlainDate(pub(crate) temporal_rs::PlainDate);
diff --git a/temporal_capi/src/plain_date_time.rs b/temporal_capi/src/plain_date_time.rs
index 9f048e33b..9b90822dc 100644
--- a/temporal_capi/src/plain_date_time.rs
+++ b/temporal_capi/src/plain_date_time.rs
@@ -7,6 +7,7 @@ pub mod ffi {
     use crate::calendar::ffi::Calendar;
     use crate::duration::ffi::Duration;
     use crate::error::ffi::TemporalError;
+    use alloc::boxed::Box;
 
     use crate::options::ffi::{
         ArithmeticOverflow, DifferenceSettings, DisplayCalendar, RoundingOptions,
@@ -14,8 +15,8 @@ pub mod ffi {
     };
     use crate::plain_date::ffi::{PartialDate, PlainDate};
     use crate::plain_time::ffi::{PartialTime, PlainTime};
+    use core::fmt::Write;
     use diplomat_runtime::DiplomatWrite;
-    use std::fmt::Write;
 
     #[diplomat::opaque]
     pub struct PlainDateTime(pub(crate) temporal_rs::PlainDateTime);
diff --git a/temporal_capi/src/plain_month_day.rs b/temporal_capi/src/plain_month_day.rs
index a326eacbb..466dea1f6 100644
--- a/temporal_capi/src/plain_month_day.rs
+++ b/temporal_capi/src/plain_month_day.rs
@@ -4,12 +4,13 @@
 pub mod ffi {
     use crate::calendar::ffi::Calendar;
     use crate::error::ffi::TemporalError;
+    use alloc::boxed::Box;
 
     use crate::options::ffi::ArithmeticOverflow;
     use crate::plain_date::ffi::{PartialDate, PlainDate};
 
+    use core::fmt::Write;
     use diplomat_runtime::DiplomatWrite;
-    use std::fmt::Write;
 
     #[diplomat::opaque]
     pub struct PlainMonthDay(pub(crate) temporal_rs::PlainMonthDay);
diff --git a/temporal_capi/src/plain_time.rs b/temporal_capi/src/plain_time.rs
index 934307ca0..37e416444 100644
--- a/temporal_capi/src/plain_time.rs
+++ b/temporal_capi/src/plain_time.rs
@@ -2,14 +2,15 @@
 #[diplomat::abi_rename = "temporal_rs_{0}"]
 #[diplomat::attr(auto, namespace = "temporal_rs")]
 pub mod ffi {
+    use alloc::boxed::Box;
 
     use crate::duration::ffi::{Duration, TimeDuration};
     use crate::error::ffi::TemporalError;
     use crate::options::ffi::{
         ArithmeticOverflow, DifferenceSettings, RoundingMode, ToStringRoundingOptions, Unit,
     };
+    use core::fmt::Write;
     use diplomat_runtime::{DiplomatOption, DiplomatWrite};
-    use std::fmt::Write;
 
     #[diplomat::opaque]
     pub struct PlainTime(pub(crate) temporal_rs::PlainTime);
diff --git a/temporal_capi/src/plain_year_month.rs b/temporal_capi/src/plain_year_month.rs
index afc1ca096..d9a2661dd 100644
--- a/temporal_capi/src/plain_year_month.rs
+++ b/temporal_capi/src/plain_year_month.rs
@@ -5,11 +5,12 @@ pub mod ffi {
     use crate::calendar::ffi::Calendar;
     use crate::duration::ffi::Duration;
     use crate::error::ffi::TemporalError;
+    use alloc::boxed::Box;
 
     use crate::options::ffi::{ArithmeticOverflow, DifferenceSettings};
     use crate::plain_date::ffi::{PartialDate, PlainDate};
+    use core::fmt::Write;
     use diplomat_runtime::DiplomatWrite;
-    use std::fmt::Write;
 
     #[diplomat::opaque]
     pub struct PlainYearMonth(pub(crate) temporal_rs::PlainYearMonth);