diff --git a/Cargo.lock b/Cargo.lock
index 673ab92..e9f29b3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -229,6 +229,7 @@ version = "0.1.0"
 dependencies = [
  "cargo-insta 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "filesize 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "insta 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "signal-hook 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
  "structopt 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -277,6 +278,14 @@ name = "fake-simd"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "filesize"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "fuchsia-cprng"
 version = "0.1.1"
@@ -1073,6 +1082,7 @@ dependencies = [
 "checksum failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "f8273f13c977665c5db7eb2b99ae520952fe5ac831ae4cd09d80c4c7042b5ed9"
 "checksum failure_derive 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "0bc225b78e0391e4b8683440bf2e63c2deeeb2ce5189eab46e2b68c6d3725d08"
 "checksum fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e88a8acf291dafb59c2d96e8f59828f3838bb1a70398823ade51a84de6a6deed"
+"checksum filesize 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "12d741e2415d4e2e5bd1c1d00409d1a8865a57892c2d689b504365655d237d43"
 "checksum fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
 "checksum generic-array 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)" = "c68f0274ae0e023facc3c97b2e00f076be70e254bc851d972503b328db79b2ec"
 "checksum getrandom 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)" = "e7db7ca94ed4cd01190ceee0d8a8052f08a247aa1b469a7f68c6a3b71afcf407"
diff --git a/Cargo.toml b/Cargo.toml
index 43cd470..aa4359d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,6 +15,7 @@ failure = "0.1"
 walkdir = "2"
 signal-hook = "0.1.10"
 structopt = "0.3"
+filesize = "0.2.0"
 
 [dev-dependencies]
 insta = "0.12.0"
diff --git a/src/state/files/file_or_folder.rs b/src/state/files/file_or_folder.rs
index 2746953..f830054 100644
--- a/src/state/files/file_or_folder.rs
+++ b/src/state/files/file_or_folder.rs
@@ -1,9 +1,10 @@
 use ::std::collections::{HashMap, VecDeque};
 use ::std::ffi::OsString;
 use ::std::fs::Metadata;
-use ::std::os::unix::fs::MetadataExt; // TODO: support other OSs
 use ::std::path::PathBuf;
 
+use ::filesize::PathExt;
+
 #[derive(Debug, Clone)]
 pub enum FileOrFolder {
     Folder(Folder),
@@ -58,7 +59,7 @@ impl Folder {
         if entry_metadata.is_dir() {
             self.add_folder(relative_path);
         } else {
-            let size = entry_metadata.blocks() * 512; // TODO: support other OSs that do not have blocks
+            let size = relative_path.size_on_disk_fast(&entry_metadata).unwrap_or(entry_metadata.len());
             self.add_file(relative_path, size);
         }
     }