diff --git a/src/sieve.rs b/src/sieve.rs
index 42038bc..eabe333 100644
--- a/src/sieve.rs
+++ b/src/sieve.rs
@@ -1,7 +1,7 @@
 pub fn get_primes(max_nr: usize) -> Vec<u64> {
     let mut sieve = vec![true; max_nr + 1];
 
-    let mut primes = Vec::new();
+    let mut primes = Vec::with_capacity(1_000_000);
 
     sieve[0] = false;
     sieve[1] = false;
@@ -12,7 +12,7 @@ pub fn get_primes(max_nr: usize) -> Vec<u64> {
     loop {
         check_off_multiples_of_nr(nr, &mut sieve);
 
-        if !find_next_prime(&mut nr, &mut sieve) {
+        if find_next_prime(&mut nr, &mut sieve).is_none() {
             break;
         }
 
@@ -22,24 +22,29 @@ pub fn get_primes(max_nr: usize) -> Vec<u64> {
     primes
 }
 
-fn find_next_prime(nr: &mut u64, sieve: &mut [bool]) -> bool {
+fn find_next_prime(nr: &mut u64, sieve: &mut [bool]) -> Option<u64> {
+    let start_idx = usize::try_from(*nr).ok()? + 1;
+
     if let Some((idx, _)) = sieve
         .iter()
         .enumerate()
-        .skip(usize::try_from(*nr).unwrap() + 1)
-        .find(|(_, val)| **val)
+        .skip(start_idx)
+        .find(|&(_, &is_prime)| is_prime)
     {
         *nr = idx as u64;
-        return true;
+        return Some(*nr);
     }
 
-    false
+    None
 }
 
 fn check_off_multiples_of_nr(nr: u64, sieve: &mut [bool]) {
+
+    let nr = usize::try_from(nr).unwrap();
+    
     sieve
         .iter_mut()
-        .skip(usize::try_from(nr * 2).unwrap())
-        .step_by(usize::try_from(nr).unwrap())
+        .skip(nr.checked_mul(2).unwrap())
+        .step_by(nr)
         .for_each(|nr| *nr = false);
 }