diff --git a/demo_markdown/docs/input/mod.md b/demo_markdown/docs/input/mod.md
index 1b00cfd..e1410fa 100644
--- a/demo_markdown/docs/input/mod.md
+++ b/demo_markdown/docs/input/mod.md
@@ -6,7 +6,7 @@ let value = RwSignal::new(String::from("o"));
 view! {
     <Space vertical=true>
         <Input value/>
-        <Input value variant=InputVariant::Password placeholder="Password"/>
+        <Input value input_type=InputType::Password placeholder="Password"/>
     </Space>
 }
 ```
@@ -83,19 +83,24 @@ view! {
 }
 ```
 
-### Input attrs
+### Custom parsing
 
 ```rust demo
+let value = RwSignal::new(String::from("loren_ipsun"));
+
+let format = move |v: String| {
+    v.replace("_", " ")
+};
+let parser = move |v: String| {
+    Some(v.replace(" ", "_"))
+};
+
 view! {
-    <Space>
-        <label for="demo-input-attrs">"Do you like cheese?"</label>
-        <Input attr:id="demo-input-attrs"/>
-    </Space>
+    <Input value parser format />
+    <p>"Underlying value: "{ value }</p>
 }
 ```
 
-
-
 ### Input Props
 
 | Name | Type | Default | Description |
diff --git a/demo_markdown/docs/spin_button/mod.md b/demo_markdown/docs/spin_button/mod.md
index 1374443..a8cae4b 100644
--- a/demo_markdown/docs/spin_button/mod.md
+++ b/demo_markdown/docs/spin_button/mod.md
@@ -30,4 +30,48 @@ let value = RwSignal::new(0);
 view! {
     <SpinButton value step_page=1 disabled=true/>
 }
+```
+
+### Custom parsing
+
+```rust demo
+let value = RwSignal::new(0.0);
+
+let format = move |v: f64| {
+    let v = v.to_string();
+    let dot_pos = v.chars().position(|c| c == '.').unwrap_or_else(|| v.chars().count());
+    let mut int: String = v.chars().take(dot_pos).collect();
+
+    let sign: String = if v.chars().take(1).collect::<String>() == String::from("-") { 
+        int = int.chars().skip(1).collect();
+        String::from("-")
+    } else { 
+        String::from("") 
+    };
+
+    let dec: String = v.chars().skip(dot_pos + 1).take(2).collect();
+
+    let int = int
+        .as_bytes()
+        .rchunks(3)
+        .rev()
+        .map(std::str::from_utf8)
+        .collect::<Result<Vec<&str>, _>>()
+        .unwrap()
+        .join(".");
+    format!("{}{},{:0<2}", sign, int, dec)
+};
+
+let parser = move |v: String| {
+    let comma_pos = v.chars().position(|c| c == ',').unwrap_or_else(|| v.chars().count());
+    let int_part = v.chars().take(comma_pos).filter(|a| a.is_digit(10)).collect::<String>();
+    let dec_part = v.chars().skip(comma_pos + 1).take(2).filter(|a| a.is_digit(10)).collect::<String>();
+    
+    format!("{:0<1}.{:0<2}", int_part, dec_part).parse::<f64>().ok()
+};
+
+view! {
+    <SpinButton value parser format step_page=1.0 />
+    <p>"Underlying value: "{ value }</p>
+}
 ```
\ No newline at end of file
diff --git a/thaw/src/input/mod.rs b/thaw/src/input/mod.rs
index b87bca2..e431d72 100644
--- a/thaw/src/input/mod.rs
+++ b/thaw/src/input/mod.rs
@@ -34,45 +34,44 @@ pub fn Input(
     #[prop(optional)] input_suffix: Option<InputSuffix>,
     #[prop(optional)] comp_ref: ComponentRef<InputRef>,
     #[prop(optional, into)] class: MaybeProp<String>,
-    #[prop(optional, into)] parser: OptionalProp<BoxOneCallback<String, String>>,
+    #[prop(optional, into)] parser: OptionalProp<BoxOneCallback<String, Option<String>>>,
     #[prop(optional, into)] format: OptionalProp<BoxOneCallback<String, String>>,
     // #[prop(attrs)] attrs: Vec<(&'static str, Attribute)>,
 ) -> impl IntoView {
     mount_style("input", include_str!("./input.css"));
 
-    let value_trigger = ArcTrigger::new();
     let parser_none = parser.is_none();
     let on_input = {
-        let value_trigger = value_trigger.clone();
         let allow_value = allow_value.clone();
-
         move |e| {
-            if parser_none {
-                let input_value = event_target_value(&e);
-                if let Some(allow_value) = allow_value.as_ref() {
-                    if !allow_value(input_value.clone()) {
-                        value_trigger.trigger();
-                        return;
-                    }
-                }
-                value.set(input_value);
+            if !parser_none {
+                return;
             }
+            let input_value = event_target_value(&e);
+            if let Some(allow_value) = allow_value.as_ref() {
+                if !allow_value(input_value.clone()) {
+                    value.update(|_| {});
+                    return;
+                }
+            }
+            value.set(input_value);
         }
     };
-    let on_change = {
-        let value_trigger = value_trigger.clone();
-        move |e| {
-            if let Some(parser) = parser.as_ref() {
-                let parsed_input_value = parser(event_target_value(&e));
-                if let Some(allow_value) = allow_value.as_ref() {
-                    if !allow_value(parsed_input_value.clone()) {
-                        value_trigger.trigger();
-                        return;
-                    }
-                }
-                value.set(parsed_input_value);
+    let on_change = move |e| {
+        let Some(parser) = parser.as_ref() else {
+            return;
+        };
+        let Some(parsed_input_value) = parser(event_target_value(&e)) else {
+            value.update(|_| {});
+            return;
+        };
+        if let Some(allow_value) = allow_value.as_ref() {
+            if !allow_value(parsed_input_value.clone()) {
+                value.update(|_| {});
+                return;
             }
         }
+        value.set(parsed_input_value);
     };
     let is_focus = RwSignal::new(false);
     let on_internal_focus = move |ev| {
@@ -152,8 +151,12 @@ pub fn Input(
                 type=move || input_type.get().as_str()
                 value=input_value
                 prop:value=move || {
-                    value_trigger.track();
-                    format.as_ref().map_or_else(|| value.get(), |f| f(value.get()))
+                    let value = value.get();
+                    if let Some(format) = format.as_ref() {
+                        format(value)
+                    } else {
+                        value.to_string()
+                    }
                 }
 
                 on:input=on_input
diff --git a/thaw/src/spin_button/mod.rs b/thaw/src/spin_button/mod.rs
index d27122f..8ab9a34 100644
--- a/thaw/src/spin_button/mod.rs
+++ b/thaw/src/spin_button/mod.rs
@@ -2,7 +2,9 @@ use leptos::prelude::*;
 use num_traits::Bounded;
 use std::ops::{Add, Sub};
 use std::str::FromStr;
-use thaw_utils::{class_list, mount_style, with, Model, StoredMaybeSignal};
+use thaw_utils::{
+    class_list, mount_style, with, BoxOneCallback, Model, OptionalProp, StoredMaybeSignal,
+};
 
 #[component]
 pub fn SpinButton<T>(
@@ -12,6 +14,8 @@ pub fn SpinButton<T>(
     #[prop(default = T::min_value().into(), into)] min: MaybeSignal<T>,
     #[prop(default = T::max_value().into(), into)] max: MaybeSignal<T>,
     #[prop(optional, into)] disabled: MaybeSignal<bool>,
+    #[prop(optional, into)] parser: OptionalProp<BoxOneCallback<String, Option<T>>>,
+    #[prop(optional, into)] format: OptionalProp<BoxOneCallback<T, String>>,
 ) -> impl IntoView
 where
     T: Send + Sync,
@@ -24,19 +28,6 @@ where
     let step_page: StoredMaybeSignal<_> = step_page.into();
     let min: StoredMaybeSignal<_> = min.into();
     let max: StoredMaybeSignal<_> = max.into();
-    let input_value = RwSignal::new(String::new());
-
-    Effect::new_isomorphic(move |prev| {
-        value.with(|value| {
-            if let Some(prev) = prev {
-                if value == &prev {
-                    return prev;
-                }
-            }
-            input_value.set(value.to_string());
-            value.clone()
-        })
-    });
 
     let update_value = move |new_value| {
         let min = min.get_untracked();
@@ -53,6 +44,21 @@ where
     let increment_disabled = Memo::new(move |_| disabled.get() || value.get() >= max.get());
     let decrement_disabled = Memo::new(move |_| disabled.get() || value.get() <= min.get());
 
+    let on_change = move |e| {
+        let target_value = event_target_value(&e);
+        let v = if let Some(parser) = parser.as_ref() {
+            parser(target_value)
+        } else {
+            target_value.parse::<T>().ok()
+        };
+
+        if let Some(value) = v {
+            update_value(value);
+        } else {
+            value.update(|_| {});
+        }
+    };
+
     view! {
         <span
             class=class_list!["thaw-spin-button", ("thaw-spin-button--disabled", move || disabled.get()), class]
@@ -64,16 +70,16 @@ where
                 type="text"
                 disabled=move || disabled.get()
                 value=initialization_value
-                prop:value=move || input_value.get()
-                class="thaw-spin-button__input"
-                on:change=move |e| {
-                    let target_value = event_target_value(&e);
-                    let Ok(v) = target_value.parse::<T>() else {
-                        input_value.update(|_| {});
-                        return;
-                    };
-                    update_value(v);
+                prop:value=move || {
+                    let value = value.get();
+                    if let Some(format) = format.as_ref() {
+                        format(value)
+                    } else {
+                        value.to_string()
+                    }
                 }
+                class="thaw-spin-button__input"
+                on:change=on_change
             />
             <button
                 tabindex="-1"
diff --git a/thaw_utils/src/optional_prop.rs b/thaw_utils/src/optional_prop.rs
index 711ccce..bcda1c3 100644
--- a/thaw_utils/src/optional_prop.rs
+++ b/thaw_utils/src/optional_prop.rs
@@ -1,6 +1,8 @@
 use leptos::prelude::{MaybeSignal, Memo, ReadSignal, RwSignal, Signal};
 use std::ops::{Deref, DerefMut};
 
+use crate::BoxOneCallback;
+
 pub struct OptionalProp<T>(Option<T>);
 
 impl<T> Default for OptionalProp<T> {
@@ -92,6 +94,15 @@ impl<T> From<Signal<T>> for OptionalProp<MaybeSignal<T>> {
     }
 }
 
+impl<F, A, Return> From<F> for OptionalProp<BoxOneCallback<A, Return>>
+where
+    F: Fn(A) -> Return + Send + Sync + 'static,
+{
+    fn from(value: F) -> Self {
+        Self(Some(BoxOneCallback::new(value)))
+    }
+}
+
 impl<T> From<Option<T>> for OptionalProp<T> {
     fn from(value: Option<T>) -> Self {
         Self(value)