diff --git a/src/evaluate/function.rs b/src/evaluate/function.rs
index ac95a3b..579032e 100644
--- a/src/evaluate/function.rs
+++ b/src/evaluate/function.rs
@@ -39,7 +39,35 @@ pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, EvalEr
 		Function::NoUnit => { return Ok(Expression::Quantity(*loc + *l, q.without_unit())); }
 		Function::ToBase => { return Ok(Expression::Quantity(*loc + *l, q.convert_to_base())); }
 
-		// Trigonometry
+
+
+		Function::Abs => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.abs()));
+		},
+		Function::Floor => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.floor()));
+		},
+		Function::Ceil => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.ceil()));
+		},
+		Function::Round => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.round()));
+		},
+		Function::NaturalLog => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.ln()));
+		},
+		Function::TenLog => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.log10()));
+		},
+
+
+
 		Function::Sin => {
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, EvalError::IncompatibleUnit)); };
 			return Ok(Expression::Quantity(*loc + *l, q.sin()));
@@ -88,44 +116,73 @@ pub fn eval_function(g: &Expression) -> Result<Expression, (LineLocation, EvalEr
 			let Ok(q) = to_radians(q.clone()) else { return Err((*loc + *l, EvalError::IncompatibleUnit)); };
 			return Ok(Expression::Quantity(*loc + *l, q.coth()));
 		},
-		_ => {}
-	}
+		Function::Asin => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.asin()));
+		},
+		Function::Acos => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.acos()));
+		},
+		Function::Atan => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.atan()));
+		},
+		Function::Asinh => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.asinh()));
+		},
+		Function::Acosh => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.acosh()));
+		},
+		Function::Atanh => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+			return Ok(Expression::Quantity(*loc + *l, q.atanh()));
+		},
 
-	if !q.unitless() {
-		return Err((*loc + *l, EvalError::IncompatibleUnit));
-	}
 
-	match f {
-		Function::Abs => { return Ok(Expression::Quantity(*loc + *l, q.abs())); },
-		Function::Floor => { return Ok(Expression::Quantity(*loc + *l, q.floor())); },
-		Function::Ceil => { return Ok(Expression::Quantity(*loc + *l, q.ceil())); },
-		Function::Round => { return Ok(Expression::Quantity(*loc + *l, q.round())); },
 
-		Function::NaturalLog => { return Ok(Expression::Quantity(*loc + *l, q.ln())); },
-		Function::TenLog => { return Ok(Expression::Quantity(*loc + *l, q.log10())); },
+		Function::ToCelsius => {
+			let mut k = Quantity::new_rational(1f64).unwrap();
+			k.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
+			let Some(q) = q.convert_to(k) else { return Err((*loc + *l, EvalError::IncompatibleUnit)) };
 
-		Function::Asin => { return Ok(Expression::Quantity(*loc + *l, q.asin())); },
-		Function::Acos => { return Ok(Expression::Quantity(*loc + *l, q.acos())); },
-		Function::Atan => { return Ok(Expression::Quantity(*loc + *l, q.atan())); },
+			let mut r = q.without_unit();
+			r += Quantity::new_rational(-273.15f64).unwrap();
 
-		Function::Asinh => { return Ok(Expression::Quantity(*loc + *l, q.asinh())); },
-		Function::Acosh => { return Ok(Expression::Quantity(*loc + *l, q.acosh())); },
-		Function::Atanh => { return Ok(Expression::Quantity(*loc + *l, q.atanh())); },
+			return Ok(Expression::Quantity(*loc + *l, r));
+		},
+		Function::ToFahrenheit => {
+			let mut k = Quantity::new_rational(1f64).unwrap();
+			k.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
+			let Some(q) = q.convert_to(k) else { return Err((*loc + *l, EvalError::IncompatibleUnit)) };
 
-		Function::ToBase
-		| Function::NoUnit
-		| Function::Sin
-		| Function::Cos
-		| Function::Tan
-		| Function::Csc
-		| Function::Sec
-		| Function::Cot
-		| Function::Sinh
-		| Function::Cosh
-		| Function::Tanh
-		| Function::Csch
-		| Function::Sech
-		| Function::Coth
-		=> unreachable!()
+			let mut r = q.without_unit();
+			r *= Quantity::new_rational_from_frac(9i64, 5i64).unwrap();
+			r += Quantity::new_rational(-459.67).unwrap();
+
+
+			return Ok(Expression::Quantity(*loc + *l, r));
+		},
+		Function::FromCelsius => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+
+			let mut r = Quantity::new_rational(273.15f64).unwrap();
+			r += q.clone();
+			r.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
+
+			return Ok(Expression::Quantity(*loc + *l, r));
+		},
+		Function::FromFahrenheit => {
+			if !q.unitless() { return Err((*loc + *l, EvalError::IncompatibleUnit));}
+
+			let mut r = q.clone();
+			r += Quantity::new_rational(459.67).unwrap();
+			r *= Quantity::new_rational_from_frac(5i64, 9i64).unwrap();
+			r.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
+
+			return Ok(Expression::Quantity(*loc + *l, r));
+		}
 	}
 }
\ No newline at end of file
diff --git a/src/parser/expression/function.rs b/src/parser/expression/function.rs
index ba73686..9c71fd5 100644
--- a/src/parser/expression/function.rs
+++ b/src/parser/expression/function.rs
@@ -33,7 +33,11 @@ pub enum Function {
 	Coth,
 
 	NoUnit,
-	ToBase
+	ToBase,
+	FromCelsius,
+	ToCelsius,
+	FromFahrenheit,
+	ToFahrenheit
 }
 
 
@@ -66,6 +70,10 @@ impl ToString for Function {
 			Function::Coth => { String::from("coth") },
 			Function::NoUnit => { String::from("nounit") },
 			Function::ToBase => { String::from("tobase") },
+			Function::FromCelsius => { String::from("fromcelsius") },
+			Function::ToCelsius => {String::from("tocelsius") },
+			Function::FromFahrenheit => { String::from("fromfahrenheit") },
+			Function::ToFahrenheit => { String::from("tofahrenheit") },
 		}
 	}
 
@@ -101,7 +109,20 @@ impl Function {
 			"coth"    => {Some(Function::Coth)},
 
 			"nounit" => {Some(Function::NoUnit)},
-			"tobase" => {Some(Function::ToBase)}
+			"tobase" => {Some(Function::ToBase)},
+
+			"toC"            => {Some(Function::ToCelsius)},
+			"fromC"          => {Some(Function::FromCelsius)},
+			"toF"            => {Some(Function::ToFahrenheit)},
+			"fromF"          => {Some(Function::FromFahrenheit)},
+			"tocelsius"      => {Some(Function::ToCelsius)},
+			"fromcelsius"    => {Some(Function::FromCelsius)},
+			"tofahrenheit"   => {Some(Function::ToFahrenheit)},
+			"fromfahrenheit" => {Some(Function::FromFahrenheit)},
+			"toCelsius"      => {Some(Function::ToCelsius)},
+			"fromCelsius"    => {Some(Function::FromCelsius)},
+			"toFahrenheit"   => {Some(Function::ToFahrenheit)},
+			"fromFahrenheit" => {Some(Function::FromFahrenheit)},
 			_ => None
 		}
 	}
diff --git a/src/quantity/quantity.rs b/src/quantity/quantity.rs
index d8cd4ab..fd63e5b 100644
--- a/src/quantity/quantity.rs
+++ b/src/quantity/quantity.rs
@@ -90,6 +90,16 @@ impl Quantity {
 		});
 	}
 
+	pub fn new_rational_from_frac(a: i64, b: i64) -> Option<Quantity> {
+		let v = Scalar::new_rational_from_frac(a, b);
+		if v.is_none() { return None; }
+
+		return Some(Quantity{
+			scalar: v.unwrap(),
+			unit: Unit::new()
+		});
+	}
+
 	pub fn from_scalar(s: Scalar) -> Quantity {
 		return Quantity{
 			scalar: s,