diff --git a/CHANGELOG.md b/CHANGELOG.md
index 91f134778..1a3aa9af6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add support for theme from [zwpaper](https://github.com/zwpaper) [#452](https://github.com/Peltoche/lsd/pull/452)
 - Update minimal rust version to 1.42.0 from [zwpaper](https://github.com/zwpaper) [#534](https://github.com/Peltoche/lsd/issues/534)
 - [`NO_COLOR`](https://no-color.org/) environment variable support from [AnInternetTroll](https://github.com/aninternettroll)
+- Added `--size bytes-with-separator` flag to print bytes with thousands separated by `,` [#533](https://github.com/Peltoche/lsd/issues/533) 
 ### Changed
 - Change size to use btyes in classic mode from [meain](https://github.com/meain)
 - Show tree edge before name block or first column if no name block from [zwpaper](https://github.com/zwpaper) [#468](https://github.com/Peltoche/lsd/issues/468)
diff --git a/Cargo.lock b/Cargo.lock
index 60204a7fb..d76667857 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,22 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "addr2line"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9ecd88a8c8378ca913a680cd98f0f13ac67383d35993f86c90a70e3f137816b"
+dependencies = [
+ "gimli",
+]
+
+[[package]]
+name = "adler"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
+
 [[package]]
 name = "aho-corasick"
 version = "0.7.18"
@@ -27,6 +44,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "arrayvec"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cd9fd44efafa8690358b7408d253adf110036b88f55672a933f01d616ad9b1b9"
+dependencies = [
+ "nodrop",
+]
+
 [[package]]
 name = "assert_cmd"
 version = "1.0.8"
@@ -72,6 +98,44 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 
+[[package]]
+name = "backtrace"
+version = "0.3.63"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "321629d8ba6513061f26707241fa9bc89524ff1cd7a915a97ef0c62c666ce1b6"
+dependencies = [
+ "addr2line",
+ "cc",
+ "cfg-if 1.0.0",
+ "libc",
+ "miniz_oxide",
+ "object",
+ "rustc-demangle",
+]
+
+[[package]]
+name = "bindgen"
+version = "0.47.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2a817f8356b784c37ee29b7a9a15c3fec321cd46b0ec67bcebe5530207f62e2d"
+dependencies = [
+ "bitflags",
+ "cexpr",
+ "cfg-if 0.1.10",
+ "clang-sys",
+ "clap",
+ "env_logger",
+ "hashbrown 0.1.8",
+ "lazy_static",
+ "log",
+ "peeking_take_while",
+ "proc-macro2 0.4.30",
+ "quote 0.6.13",
+ "regex",
+ "shlex",
+ "which",
+]
+
 [[package]]
 name = "bitflags"
 version = "1.2.1"
@@ -89,6 +153,33 @@ dependencies = [
  "regex-automata",
 ]
 
+[[package]]
+name = "byteorder"
+version = "1.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14c189c53d098945499cdfa7ecc63567cf3886b3332b312a5b4585d8d3a6a610"
+
+[[package]]
+name = "cc"
+version = "1.0.71"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "79c2681d6594606957bbb8631c4b90a7fcaaa72cdb714743a437b156d6a7eedd"
+
+[[package]]
+name = "cexpr"
+version = "0.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fce5b5fb86b0c57c20c834c1b412fd09c77c8a59b9473f86272709e78874cd1d"
+dependencies = [
+ "nom",
+]
+
+[[package]]
+name = "cfg-if"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -117,6 +208,17 @@ dependencies = [
  "chrono",
 ]
 
+[[package]]
+name = "clang-sys"
+version = "0.26.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ef0c1bcf2e99c649104bd7a7012d8f8802684400e03db0ec0af48583c6fa0e4"
+dependencies = [
+ "glob 0.2.11",
+ "libc",
+ "libloading",
+]
+
 [[package]]
 name = "clap"
 version = "2.33.3"
@@ -139,7 +241,7 @@ version = "0.8.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d82cfc11ce7f2c3faef78d8a684447b40d503d9681acebed6cb728d45940c4db"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "lazy_static",
 ]
 
@@ -219,6 +321,37 @@ version = "1.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
 
+[[package]]
+name = "encoding_rs"
+version = "0.8.29"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a74ea89a0a1b98f6332de42c95baff457ada66d1cb4030f9ff151b2041a1c746"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
+[[package]]
+name = "env_logger"
+version = "0.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "aafcde04e90a5226a6443b7aabdb016ba2f8307c847d524724bd9b346dd1a2d3"
+dependencies = [
+ "atty",
+ "humantime",
+ "log",
+ "regex",
+ "termcolor",
+]
+
+[[package]]
+name = "failure"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d32e9bd16cc02eae7db7ef620b392808b89f6a5e16bb3497d159c6b92a0f4f86"
+dependencies = [
+ "backtrace",
+]
+
 [[package]]
 name = "float-cmp"
 version = "0.8.0"
@@ -240,11 +373,23 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7fcd999463524c52659517fe2cea98493cfe485d10565e7b0fb07dbba7ad2753"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "libc",
  "wasi",
 ]
 
+[[package]]
+name = "gimli"
+version = "0.26.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78cc372d058dcf6d5ecd98510e7fbc9e5aec4d21de70f65fea8fecebcd881bd4"
+
+[[package]]
+name = "glob"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8be18de09a56b60ed0edf84bc9df007e30040691af7acd1c41874faac5895bfb"
+
 [[package]]
 name = "glob"
 version = "0.3.0"
@@ -275,6 +420,16 @@ dependencies = [
  "walkdir",
 ]
 
+[[package]]
+name = "hashbrown"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3bae29b6653b3412c2e71e9d486db9f9df5d701941d86683005efb9f2d28e3da"
+dependencies = [
+ "byteorder",
+ "scopeguard 0.3.3",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.11.2"
@@ -296,6 +451,15 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "140a09c9305e6d5e557e2ed7cbc68e05765a7d4213975b87cb04920689cc6219"
 
+[[package]]
+name = "humantime"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
+dependencies = [
+ "quick-error",
+]
+
 [[package]]
 name = "ignore"
 version = "0.4.18"
@@ -321,7 +485,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bc633605454125dec4b66843673f01c7df2b89479b32e0ed634e43a91cff62a5"
 dependencies = [
  "autocfg",
- "hashbrown",
+ "hashbrown 0.11.2",
 ]
 
 [[package]]
@@ -330,7 +494,7 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bee0328b1209d157ef001c94dd85b4f8f64139adb0eac2659f4b08382b2f474d"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
 ]
 
 [[package]]
@@ -342,6 +506,12 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "itoa"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b71991ff56294aa922b450139ee08b3bfc70982c6b2c7562771375cf73542dd4"
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -354,6 +524,16 @@ version = "0.2.100"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a1fa8cddc8fbbee11227ef194b5317ed014b8acbf15139bd716a18ad3fe99ec5"
 
+[[package]]
+name = "libloading"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2b111a074963af1d37a139918ac6d49ad1d0d5e47f72fd55388619691a7d753"
+dependencies = [
+ "cc",
+ "winapi",
+]
+
 [[package]]
 name = "linked-hash-map"
 version = "0.5.4"
@@ -366,7 +546,7 @@ version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0382880606dff6d15c9476c416d18690b72742aa7b605bb6dd6ec9030fbf07eb"
 dependencies = [
- "scopeguard",
+ "scopeguard 1.1.0",
 ]
 
 [[package]]
@@ -375,7 +555,7 @@ version = "0.4.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "51b9bbe6c47d51fc3e1a9b945965946b4c44142ab8792c50835a980d362c2710"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
 ]
 
 [[package]]
@@ -403,6 +583,7 @@ dependencies = [
  "human-sort",
  "libc",
  "lscolors",
+ "num-format",
  "predicates 1.0.8",
  "serde",
  "serde_yaml",
@@ -412,7 +593,7 @@ dependencies = [
  "terminal_size",
  "unicode-width",
  "users",
- "version_check",
+ "version_check 0.9.3",
  "wild",
  "winapi",
  "xdg",
@@ -425,6 +606,16 @@ version = "2.4.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "308cc39be01b73d0d18f82a0e7b2a3df85245f84af96fdddc5d202d27e47b86a"
 
+[[package]]
+name = "miniz_oxide"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a92518e98c078586bc6c934028adcca4c92a53d6a958196de835170a01d84e4b"
+dependencies = [
+ "adler",
+ "autocfg",
+]
+
 [[package]]
 name = "mio"
 version = "0.7.13"
@@ -447,6 +638,22 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "nodrop"
+version = "0.1.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "72ef4a56884ca558e5ddb05a1d1e7e1bfd9a68d9ed024c21704cc98872dae1bb"
+
+[[package]]
+name = "nom"
+version = "4.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2ad2a91a8e869eeb30b9cb3119ae87773a8f4ae617f41b1eb9c154b2905f7bd6"
+dependencies = [
+ "memchr",
+ "version_check 0.1.5",
+]
+
 [[package]]
 name = "normalize-line-endings"
 version = "0.3.0"
@@ -462,6 +669,32 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "num-format"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bafe4179722c2894288ee77a9f044f02811c86af699344c498b0840c698a2465"
+dependencies = [
+ "arrayvec",
+ "cfg-if 0.1.10",
+ "encoding_rs",
+ "itoa",
+ "lazy_static",
+ "libc",
+ "num-format-windows",
+ "widestring",
+ "winapi",
+]
+
+[[package]]
+name = "num-format-windows"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4e179850c4611faf725cc7d92016aa9261a4c9887fc5501812da6cb87297c5eb"
+dependencies = [
+ "bindgen",
+]
+
 [[package]]
 name = "num-integer"
 version = "0.1.44"
@@ -481,6 +714,15 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "object"
+version = "0.27.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67ac1d3f9a1d3616fd9a60c8d74296f22406a238b6a72f5cc1e6f314df4ffbf9"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "once_cell"
 version = "1.8.0"
@@ -504,7 +746,7 @@ version = "0.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fa7a782938e745763fe6907fc6ba86946d72f49fe7e21de074e08128a99fb018"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "instant",
  "libc",
  "redox_syscall",
@@ -512,6 +754,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "peeking_take_while"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "19b17cddbe7ec3f8bc800887bab5e717348c95ea2ca0b1bf0837fb964dc67099"
+
 [[package]]
 name = "ppv-lite86"
 version = "0.2.10"
@@ -558,13 +806,37 @@ dependencies = [
  "treeline",
 ]
 
+[[package]]
+name = "proc-macro2"
+version = "0.4.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
+dependencies = [
+ "unicode-xid 0.1.0",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5c7ed8b8c7b886ea3ed7dde405212185f423ab44682667c8c6dd14aa1d9f6612"
 dependencies = [
- "unicode-xid",
+ "unicode-xid 0.2.2",
+]
+
+[[package]]
+name = "quick-error"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
+
+[[package]]
+name = "quote"
+version = "0.6.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
+dependencies = [
+ "proc-macro2 0.4.30",
 ]
 
 [[package]]
@@ -573,7 +845,7 @@ version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c3d0b9745dc2debf507c8422de05d7226cc1f0644216dfdfead988f9b1ab32a7"
 dependencies = [
- "proc-macro2",
+ "proc-macro2 1.0.28",
 ]
 
 [[package]]
@@ -667,6 +939,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "rustc-demangle"
+version = "0.1.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7ef03e0a2b150c7a90d01faf6254c9c48a41e95fb2a8c2ac1c6f0d2b9aefc342"
+
 [[package]]
 name = "same-file"
 version = "1.0.6"
@@ -676,6 +954,12 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94258f53601af11e6a49f722422f6e3425c52b06245a5cf9bc09908b174f5e27"
+
 [[package]]
 name = "scopeguard"
 version = "1.1.0"
@@ -697,8 +981,8 @@ version = "1.0.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e57ae87ad533d9a56427558b516d0adac283614e347abf85b0dc0cbbf0a249f3"
 dependencies = [
- "proc-macro2",
- "quote",
+ "proc-macro2 1.0.28",
+ "quote 1.0.9",
  "syn",
 ]
 
@@ -731,11 +1015,17 @@ version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b2acd6defeddb41eb60bb468f8825d0cfd0c2a76bc03bfd235b6a1dc4f6a1ad5"
 dependencies = [
- "proc-macro2",
- "quote",
+ "proc-macro2 1.0.28",
+ "quote 1.0.9",
  "syn",
 ]
 
+[[package]]
+name = "shlex"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fdf1b9db47230893d76faad238fd6097fd6d6a9245cd7a4d90dbd639536bbd2"
+
 [[package]]
 name = "signal-hook"
 version = "0.3.9"
@@ -784,9 +1074,9 @@ version = "1.0.75"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b7f58f7e8eaa0009c5fec437aabf511bd9933e4b2d7407bd05273c01a8906ea7"
 dependencies = [
- "proc-macro2",
- "quote",
- "unicode-xid",
+ "proc-macro2 1.0.28",
+ "quote 1.0.9",
+ "unicode-xid 0.2.2",
 ]
 
 [[package]]
@@ -795,7 +1085,7 @@ version = "3.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dac1c663cfc93810f88aed9b8941d48cabf856a1b111c29a40439018d870eb22"
 dependencies = [
- "cfg-if",
+ "cfg-if 1.0.0",
  "libc",
  "rand",
  "redox_syscall",
@@ -822,6 +1112,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dfed899f0eb03f32ee8c6a0aabdb8a7949659e3466561fc0adf54e26d88c5f4"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "terminal_size"
 version = "0.1.17"
@@ -873,6 +1172,12 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
 
+[[package]]
+name = "unicode-xid"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
+
 [[package]]
 name = "unicode-xid"
 version = "0.2.2"
@@ -895,6 +1200,12 @@ version = "0.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 
+[[package]]
+name = "version_check"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "914b1a6776c4c929a602fafd8bc742e06365d4bcbe48c30f9cca5824f70dc9dd"
+
 [[package]]
 name = "version_check"
 version = "0.9.3"
@@ -927,13 +1238,29 @@ version = "0.10.2+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
 
+[[package]]
+name = "which"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b57acb10231b9493c8472b20cb57317d0679a49e0bdbee44b3b803a6473af164"
+dependencies = [
+ "failure",
+ "libc",
+]
+
+[[package]]
+name = "widestring"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c168940144dd21fd8046987c16a46a33d5fc84eec29ef9dcddc2ac9e31526b7c"
+
 [[package]]
 name = "wild"
 version = "2.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "035793abb854745033f01a07647a79831eba29ec0be377205f2a25b0aa830020"
 dependencies = [
- "glob",
+ "glob 0.3.0",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 62b3a0aa9..d41f30aa8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -39,10 +39,12 @@ serde = { version = "1.0", features = ["derive"] }
 serde_yaml = "0.8"
 
 [target.'cfg(unix)'.dependencies]
+num-format = { version = "0.4", features = ["with-system-locale"] }
 users = "0.11.*"
 
 [target.'cfg(windows)'.dependencies]
 winapi = {version = "0.3.*", features = ["aclapi", "accctrl", "winnt", "winerror", "securitybaseapi", "winbase"]}
+num-format = { version = "0.4" }
 
 [dependencies.clap]
 features = ["suggestions", "color", "wrap_help"]
diff --git a/src/app.rs b/src/app.rs
index 86bdf474a..575c08c08 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -131,6 +131,7 @@ pub fn build() -> App<'static, 'static> {
                 .possible_value("default")
                 .possible_value("short")
                 .possible_value("bytes")
+                .possible_value("bytes-with-separator")
                 .default_value("default")
                 .multiple(true)
                 .number_of_values(1)
diff --git a/src/flags/size.rs b/src/flags/size.rs
index 9f40d6a5d..bda6f4431 100644
--- a/src/flags/size.rs
+++ b/src/flags/size.rs
@@ -18,6 +18,8 @@ pub enum SizeFlag {
     Short,
     /// The variant to show file size in bytes.
     Bytes,
+    /// The variant to show file size in bytes with thousand separated by delimiter.
+    BytesWithSeparator,
 }
 
 impl SizeFlag {
@@ -26,9 +28,10 @@ impl SizeFlag {
             "default" => Some(Self::Default),
             "short" => Some(Self::Short),
             "bytes" => Some(Self::Bytes),
+            "bytes-with-separator" => Some(Self::BytesWithSeparator),
             _ => {
                 panic!(
-                    "Size can only be one of default, short or bytes, but got {}.",
+                    "Size can only be one of default, short, bytes or bytes-with-separator, but got {}.",
                     value
                 );
             }
@@ -170,4 +173,14 @@ mod test {
         c.classic = Some(true);
         assert_eq!(Some(SizeFlag::Bytes), SizeFlag::from_config(&c));
     }
+
+    #[test]
+    fn test_from_arg_matches_size_bytes_with_separators() {
+        let args = vec!["lsd", "--size", "bytes-with-separator"];
+        let matches = app::build().get_matches_from_safe(args).unwrap();
+        assert_eq!(
+            Some(SizeFlag::BytesWithSeparator),
+            SizeFlag::from_arg_matches(&matches)
+        );
+    }
 }
diff --git a/src/meta/size.rs b/src/meta/size.rs
index 5a16bd4dc..6a26cbcb4 100644
--- a/src/meta/size.rs
+++ b/src/meta/size.rs
@@ -1,5 +1,6 @@
 use crate::color::{ColoredString, Colors, Elem};
 use crate::flags::{Flags, SizeFlag};
+use num_format::ToFormattedString;
 use std::fs::Metadata;
 use std::iter::repeat;
 
@@ -38,8 +39,33 @@ impl Size {
         format!("{0:.1$}", number, if number < 10.0 { 1 } else { 0 })
     }
 
+    fn format_bytes(&self, flags: &Flags) -> String {
+        if flags.size == SizeFlag::BytesWithSeparator {
+            self.os_formatted_bytes()
+        } else {
+            self.bytes.to_string()
+        }
+    }
+
+    #[cfg(unix)]
+    fn os_formatted_bytes(&self) -> String {
+        if let Ok(system_locale) = num_format::SystemLocale::default() {
+            self.bytes.to_formatted_string(&system_locale)
+        } else {
+            self.bytes.to_formatted_string(&num_format::Locale::en)
+        }
+    }
+
+    #[cfg(not(unix))]
+    fn os_formatted_bytes(&self) -> String {
+        self.bytes.to_formatted_string(&num_format::Locale::en)
+    }
+
     pub fn get_unit(&self, flags: &Flags) -> Unit {
-        if self.bytes < 1024 || flags.size == SizeFlag::Bytes {
+        if self.bytes < 1024
+            || flags.size == SizeFlag::Bytes
+            || flags.size == SizeFlag::BytesWithSeparator
+        {
             Unit::Byte
         } else if self.bytes < 1024 * 1024 {
             Unit::Kilo
@@ -111,7 +137,7 @@ impl Size {
 
         match unit {
             Unit::None => "".to_string(),
-            Unit::Byte => self.bytes.to_string(),
+            Unit::Byte => self.format_bytes(flags),
             Unit::Kilo => self.format_size(((self.bytes as f64) / 1024.0 * 10.0).round() / 10.0),
             Unit::Mega => {
                 self.format_size(((self.bytes as f64) / (1024.0 * 1024.0) * 10.0).round() / 10.0)
@@ -151,7 +177,7 @@ impl Size {
                 Unit::Giga => String::from("G"),
                 Unit::Tera => String::from("T"),
             },
-            SizeFlag::Bytes => String::from(""),
+            SizeFlag::Bytes | SizeFlag::BytesWithSeparator => String::from(""),
         }
     }
 }
@@ -161,6 +187,7 @@ mod test {
     use super::Size;
     use crate::color::{Colors, ThemeOption};
     use crate::flags::{Flags, SizeFlag};
+    use std::env;
 
     #[test]
     fn render_byte() {
@@ -336,4 +363,36 @@ mod test {
         assert_eq!(size.render(&colors, &flags, Some(2)).to_string(), "42K");
         assert_eq!(size.render(&colors, &flags, Some(3)).to_string(), " 42K");
     }
+
+    #[cfg(unix)]
+    #[test]
+    fn render_bytes_with_separator() {
+        env::set_var("LC_ALL", "en-US");
+        env::set_var("LC_NUMERIC", ",");
+        let size = Size::new(42 * 1024 * 1024); // == 42 megabytes
+        let mut flags = Flags::default();
+
+        flags.size = SizeFlag::Bytes;
+        assert_eq!(size.value_string(&flags).as_str(), "44040192");
+        assert_eq!(size.unit_string(&flags).as_str(), "");
+
+        flags.size = SizeFlag::BytesWithSeparator;
+        assert_eq!(size.value_string(&flags).as_str(), "44,040,192");
+        assert_eq!(size.unit_string(&flags).as_str(), "");
+    }
+
+    #[cfg(not(unix))]
+    #[test]
+    fn render_bytes_with_separator() {
+        let size = Size::new(42 * 1024 * 1024); // == 42 megabytes
+        let mut flags = Flags::default();
+
+        flags.size = SizeFlag::Bytes;
+        assert_eq!(size.value_string(&flags).as_str(), "44040192");
+        assert_eq!(size.unit_string(&flags).as_str(), "");
+
+        flags.size = SizeFlag::BytesWithSeparator;
+        assert_eq!(size.value_string(&flags).as_str(), "44,040,192");
+        assert_eq!(size.unit_string(&flags).as_str(), "");
+    }
 }