diff --git a/crates/cuda_builder/src/lib.rs b/crates/cuda_builder/src/lib.rs
index 6441b827..3620c50a 100644
--- a/crates/cuda_builder/src/lib.rs
+++ b/crates/cuda_builder/src/lib.rs
@@ -266,6 +266,21 @@ impl CudaBuilder {
         self
     }
 
+    /// Enable fast math approximations globally (equivalent to NVCC's `--use_fast_math`).
+    /// Sets `ftz=true`, `fast_sqrt=true`, `fast_div=true`, and `fma_contraction=true`.
+    /// Individual flags can still be overridden afterward.
+    ///
+    /// Note: this sacrifices IEEE 754 compliance for performance. Single-precision
+    /// division and square root will have up to 2 ULP error, and denormal values
+    /// will be flushed to zero.
+    pub fn fast_math(mut self) -> Self {
+        self.ftz = true;
+        self.fast_sqrt = true;
+        self.fast_div = true;
+        self.fma_contraction = true;
+        self
+    }
+
     /// Use a fast approximation for single-precision floating point square root.
     pub fn fast_sqrt(mut self, fast_sqrt: bool) -> Self {
         self.fast_sqrt = fast_sqrt;