diff --git a/src/interlace.rs b/src/interlace.rs
index 96b05fd3..b4670cf5 100644
--- a/src/interlace.rs
+++ b/src/interlace.rs
@@ -118,10 +118,8 @@ fn deinterlace_bits(png: &PngImage) -> Vec<u8> {
     let mut current_y: usize = pass_constants.y_shift as usize;
     for line in png.scan_lines(false) {
         let bit_vec = line.data.view_bits::<Msb0>();
-        let bits_in_line = ((png.ihdr.width - u32::from(pass_constants.x_shift)
-            + u32::from(pass_constants.x_step)
-            - 1)
-            / u32::from(pass_constants.x_step)) as usize
+        let bits_in_line = (png.ihdr.width - u32::from(pass_constants.x_shift))
+            .div_ceil(u32::from(pass_constants.x_step)) as usize
             * bits_per_pixel;
         for (i, bit) in bit_vec.iter().by_vals().enumerate() {
             // Avoid moving padded 0's into new image