diff --git a/Cargo.lock b/Cargo.lock
index 15c51a1..0765f34 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -48,6 +48,30 @@ name = "bitflags"
 version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "block-buffer"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "block-padding 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byte-tools 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "generic-array 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "block-padding"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byte-tools 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "byte-tools"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "byteorder"
 version = "1.3.2"
@@ -83,6 +107,14 @@ dependencies = [
  "libdbus-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "digest"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "generic-array 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "dlib"
 version = "0.4.1"
@@ -96,11 +128,29 @@ name = "downcast-rs"
 version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "dtoa"
+version = "0.4.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "fake-simd"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "fuzzy-matcher"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "generic-array"
+version = "0.12.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "typenum 1.11.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.3.0"
@@ -159,6 +209,11 @@ dependencies = [
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "maplit"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "memmap"
 version = "0.7.0"
@@ -197,6 +252,24 @@ name = "nodrop"
 version = "0.1.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "num-bigint"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "num-integer 0.1.41 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "num-complex"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "autocfg 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "num-integer"
 version = "0.1.41"
@@ -206,6 +279,17 @@ dependencies = [
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "num-rational"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "autocfg 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-bigint 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-integer 0.1.41 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.8"
@@ -214,6 +298,11 @@ dependencies = [
  "autocfg 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "opaque-debug"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "ordered-float"
 version = "1.0.2"
@@ -231,6 +320,45 @@ dependencies = [
  "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "pest"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ucd-trie 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "pest_derive"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "pest 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_generator 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "pest_generator"
+version = "2.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "pest 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_meta 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.44 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "pest_meta"
+version = "2.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "maplit 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "sha-1 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "pkg-config"
 version = "0.3.15"
@@ -252,6 +380,21 @@ dependencies = [
  "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rcalc_lib"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "dtoa 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-bigint 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-complex 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-rational 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest 2.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "pest_derive 2.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.1.56"
@@ -276,6 +419,17 @@ dependencies = [
  "winapi-util 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "sha-1"
+version = "0.8.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "block-buffer 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "digest 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fake-simd 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "opaque-debug 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "smithay-client-toolkit"
 version = "0.6.3"
@@ -299,6 +453,16 @@ dependencies = [
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "syn"
+version = "0.15.44"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "time"
 version = "0.1.42"
@@ -309,6 +473,16 @@ dependencies = [
  "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "typenum"
+version = "1.11.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "ucd-trie"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "unicode-xid"
 version = "0.1.0"
@@ -424,6 +598,7 @@ dependencies = [
  "memmap 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "nix 0.14.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "os_pipe 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rcalc_lib 0.9.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rusttype 0.7.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "smithay-client-toolkit 0.6.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "wayland-client 0.23.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -447,14 +622,21 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)" = "1803c647a3ec87095e7ae7acfca019e98de5ec9a7d01343f611cf3152ed71a90"
 "checksum autocfg 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "22130e92352b948e7e82a49cdb0aa94f2211761117f29e052dd397c1ac33542b"
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 "checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum walkdir 2.2.9 (registry+https://github.com/rust-lang/crates.io-index)" = "9658c94fa8b940eab2250bd5a457f9c48b748420d71293b165c8cdbe2f55f71e"
diff --git a/Cargo.toml b/Cargo.toml
index 391e015..4d0489d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,9 +8,10 @@ edition = "2018"
 lto = "fat"
 
 [features]
+default = [ "rcalc" ]
 ivy = [ "libivy" ]
 bc = []
-default = []
+rcalc = [ "rcalc_lib" ]
 
 [dependencies]
 smithay-client-toolkit = "0.6.3"
@@ -28,3 +29,4 @@ atty = "0.2"
 fuzzy-matcher = "0.2"
 lazy_static = "1.3.0"
 libivy = { git = "https://github.com/kennylevinsen/libivy.git", optional = true }
+rcalc_lib = { version = "0.9.3", optional = true }
diff --git a/src/modules/launcher.rs b/src/modules/launcher.rs
index e266157..fcd2721 100644
--- a/src/modules/launcher.rs
+++ b/src/modules/launcher.rs
@@ -181,6 +181,13 @@ fn calc(s: &str) -> Result<String, String> {
     libivy::eval(s)
 }
 
+#[cfg(feature = "rcalc")]
+fn calc(s: &str) -> Result<String, String> {
+    rcalc_lib::parse::eval(s, &mut rcalc_lib::parse::CalcState::new())
+        .map(|x| format!("{}", x).to_string())
+        .map_err(|x| format!("{}", x).to_string())
+}
+
 #[cfg(feature = "bc")]
 fn calc(s: &str) -> Result<String, String> {
     use std::io::Write;
@@ -209,7 +216,7 @@ fn calc(s: &str) -> Result<String, String> {
         .to_string())
 }
 
-#[cfg(not(any(feature = "ivy", feature = "bc")))]
+#[cfg(not(any(feature = "ivy", feature = "bc", feature = "rcalc")))]
 fn calc(_s: &str) -> Result<String, String> {
     Err("no calculator implementation available".to_string())
 }