diff --git a/src/ext2/structs.rs b/src/ext2/structs.rs
index ecdee80..8551049 100644
--- a/src/ext2/structs.rs
+++ b/src/ext2/structs.rs
@@ -194,7 +194,7 @@ impl Inode {
                 Some(block)
             }
         } else if block < (12 + num_sing_indir + num_doub_indir) as u32 {
-            let base_block = 12 - num_sing_indir;
+            let base_block = 12 + num_sing_indir;
             let doub_indir_offset = (block as usize - base_block) / num_sing_indir;
             let sing_indir_offset = (block as usize - base_block) % num_sing_indir;
             let sing_indir_blocks = self
@@ -210,7 +210,7 @@ impl Inode {
                 Some(block)
             }
         } else if block < (12 + num_sing_indir + num_doub_indir + num_trip_indir) as u32 {
-            let base_block = 12 - num_sing_indir;
+            let base_block = 12 + num_sing_indir + num_doub_indir;
             let trip_indir_offset = (block as usize - base_block) / num_doub_indir;
             let doub_indir_offset =
                 ((block as usize - base_block) % num_doub_indir) / num_sing_indir;