diff --git a/fj-app/src/args.rs b/fj-app/src/args.rs
index f47d14120..16cada701 100644
--- a/fj-app/src/args.rs
+++ b/fj-app/src/args.rs
@@ -1,4 +1,7 @@
-use std::path::PathBuf;
+use std::{path::PathBuf, str::FromStr as _};
+
+use fj_kernel::algorithms::Tolerance;
+use fj_math::Scalar;
 
 /// Fornjot - Experimental CAD System
 #[derive(clap::Parser)]
@@ -16,8 +19,8 @@ pub struct Args {
     pub parameters: Vec<String>,
 
     /// Model deviation tolerance
-    #[clap[short, long]]
-    pub tolerance: Option<f64>,
+    #[clap[short, long, parse(try_from_str = parse_tolerance)]]
+    pub tolerance: Option<Tolerance>,
 }
 
 impl Args {
@@ -29,3 +32,11 @@ impl Args {
         <Self as clap::Parser>::parse()
     }
 }
+
+fn parse_tolerance(input: &str) -> anyhow::Result<Tolerance> {
+    let tolerance = f64::from_str(input)?;
+    let tolerance = Scalar::from_f64(tolerance);
+    let tolerance = Tolerance::from_scalar(tolerance)?;
+
+    Ok(tolerance)
+}
diff --git a/fj-app/src/main.rs b/fj-app/src/main.rs
index ea1e832f4..91008970e 100644
--- a/fj-app/src/main.rs
+++ b/fj-app/src/main.rs
@@ -242,22 +242,7 @@ struct ShapeProcessor {
 }
 
 impl ShapeProcessor {
-    fn new(tolerance: Option<f64>) -> anyhow::Result<Self> {
-        if let Some(tolerance) = tolerance {
-            if tolerance <= 0. {
-                anyhow::bail!(
-                    "Invalid user defined model deviation tolerance: {}.\n\
-                    Tolerance must be larger than zero",
-                    tolerance
-                );
-            }
-        }
-
-        let tolerance = tolerance
-            .map(Scalar::from_f64)
-            .map(Tolerance::from_scalar)
-            .map(|result| result.unwrap());
-
+    fn new(tolerance: Option<Tolerance>) -> anyhow::Result<Self> {
         Ok(Self { tolerance })
     }