diff --git a/src/lib.rs b/src/lib.rs
index 9fa2159..e68f0bf 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -187,7 +187,6 @@ FpMul:
 
 
 */
-#![feature(int_roundings)]
 mod check_carry_to_zero;
 mod lookup_range_check;
 mod mul_cfgs;
diff --git a/src/lookup_range_check.rs b/src/lookup_range_check.rs
index 9d7f238..c820741 100644
--- a/src/lookup_range_check.rs
+++ b/src/lookup_range_check.rs
@@ -213,7 +213,8 @@ impl<F: PrimeFieldBits, const K: usize> LookupRangeCheckConfig<F, { K }> {
     ) -> Result<RunningSum<F>, Error> {
         // `num_bits` must fit into a single field element.
         assert!(num_bits <= F::CAPACITY as usize);
-        let num_words = num_bits.div_ceil(K);
+        // use (a + b - 1) / b to get the ceiling of a/b instead of unstable `div_ceil`
+        let num_words = (num_bits + K - 1) / K;
 
         // Chunk the first num_bits bits into K-bit words.
         let words = {