diff --git a/src/bridge.rs b/src/bridge.rs
index b9959d5..87f6712 100644
--- a/src/bridge.rs
+++ b/src/bridge.rs
@@ -10,7 +10,10 @@ use tokio::sync::mpsc;
 pub enum UICoreMsg {
     SendLightning(Bolt11Invoice),
     ReceiveLightning(Amount),
-    SendOnChain { address: Address, amount_sats: u64 },
+    SendOnChain {
+        address: Address,
+        amount_sats: Option<u64>,
+    },
     ReceiveOnChain,
     GetFederationInfo(InviteCode),
     AddFederation(InviteCode),
@@ -71,7 +74,7 @@ impl UIHandle {
         self.msg_send(UICoreMsg::SendLightning(invoice)).await;
     }
 
-    pub async fn send_onchain(&self, address: Address, amount_sats: u64) {
+    pub async fn send_onchain(&self, address: Address, amount_sats: Option<u64>) {
         self.msg_send(UICoreMsg::SendOnChain {
             address,
             amount_sats,
diff --git a/src/core.rs b/src/core.rs
index 231e83f..5ad1a51 100644
--- a/src/core.rs
+++ b/src/core.rs
@@ -191,19 +191,37 @@ impl HarborCore {
         Ok(invoice)
     }
 
-    async fn send_onchain(&self, address: Address, sats: u64) -> anyhow::Result<()> {
+    /// Sends a given amount of sats to a given address, if the amount is None, send all funds
+    async fn send_onchain(&self, address: Address, sats: Option<u64>) -> anyhow::Result<()> {
         // todo go through all clients and select the first one that has enough balance
         let client = self.get_client().await.fedimint_client;
         let onchain = client.get_first_module::<WalletClientModule>();
 
-        let amount = bitcoin::Amount::from_sat(sats);
-
         // todo add manual fee selection
-        let fees = onchain.get_withdraw_fees(address.clone(), amount).await?;
+        let (fees, amount) = match sats {
+            Some(sats) => {
+                let amount = bitcoin::Amount::from_sat(sats);
+                let fees = onchain.get_withdraw_fees(address.clone(), amount).await?;
+                (fees, amount)
+            }
+            None => {
+                let balance = client.get_balance().await;
+                // get fees for the entire balance
+                let fees = onchain
+                    .get_withdraw_fees(
+                        address.clone(),
+                        bitcoin::Amount::from_sat(balance.sats_round_down()),
+                    )
+                    .await?;
+
+                let fees_paid = Amount::from_sats(fees.amount().to_sat());
+                let amount = balance - fees_paid;
+
+                (fees, bitcoin::Amount::from_sat(amount.sats_round_down()))
+            }
+        };
 
-        let op_id = onchain
-            .withdraw(address.clone(), bitcoin::Amount::from_sat(sats), fees, ())
-            .await?;
+        let op_id = onchain.withdraw(address.clone(), amount, fees, ()).await?;
 
         self.storage.create_onchain_payment(
             op_id,
diff --git a/src/main.rs b/src/main.rs
index 4ffd7f8..d7894cf 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -86,6 +86,7 @@ pub enum Message {
     ReceiveStateReset,
     SendDestInputChanged(String),
     SendAmountInputChanged(String),
+    SetIsMax(bool),
     SendStateReset,
     PasswordInputChanged(String),
     MintInviteCodeInputChanged(String),
@@ -117,6 +118,7 @@ pub struct HarborWallet {
     send_success_msg: Option<SendSuccessMsg>,
     send_dest_input_str: String,
     send_amount_input_str: String,
+    is_max: bool,
     password_input_str: String,
     unlock_status: UnlockStatus,
     unlock_failure_reason: Option<String>,
@@ -156,7 +158,7 @@ impl HarborWallet {
     async fn async_send_onchain(
         ui_handle: Option<Arc<bridge::UIHandle>>,
         address: Address,
-        amount_sats: u64,
+        amount_sats: Option<u64>,
     ) {
         println!("Got to async_send");
         if let Some(ui_handle) = ui_handle {
@@ -236,6 +238,10 @@ impl HarborWallet {
                 self.send_amount_input_str = input;
                 Command::none()
             }
+            Message::SetIsMax(is_max) => {
+                self.is_max = is_max;
+                Command::none()
+            }
             Message::PasswordInputChanged(input) => {
                 self.password_input_str = input;
                 Command::none()
@@ -253,6 +259,7 @@ impl HarborWallet {
                 self.send_success_msg = None;
                 self.send_dest_input_str = String::new();
                 self.send_amount_input_str = String::new();
+                self.is_max = false;
                 self.send_status = SendStatus::Idle;
                 Command::none()
             }
@@ -282,7 +289,12 @@ impl HarborWallet {
                             |_| Message::Noop,
                         )
                     } else if let Ok(address) = Address::from_str(&invoice_str) {
-                        let amount = self.send_amount_input_str.parse::<u64>().unwrap(); // TODO: error handling
+                        let amount = if self.is_max {
+                            None
+                        } else {
+                            // TODO: error handling
+                            Some(self.send_amount_input_str.parse::<u64>().unwrap())
+                        };
                         Command::perform(
                             Self::async_send_onchain(self.ui_handle.clone(), address, amount),
                             |_| Message::Noop,
@@ -326,7 +338,7 @@ impl HarborWallet {
                     let address = Address::from_str(hardcoded_donation_address).unwrap();
 
                     Command::perform(
-                        Self::async_send_onchain(self.ui_handle.clone(), address, amount),
+                        Self::async_send_onchain(self.ui_handle.clone(), address, Some(amount)),
                         |_| Message::Noop,
                     )
                 }
diff --git a/src/routes/send.rs b/src/routes/send.rs
index f7b97b4..7ce2f50 100644
--- a/src/routes/send.rs
+++ b/src/routes/send.rs
@@ -1,4 +1,4 @@
-use iced::widget::{column, container, scrollable, text};
+use iced::widget::{column, container, scrollable, text, Checkbox};
 use iced::{Color, Length};
 use iced::{Element, Padding};
 
@@ -8,6 +8,7 @@ use crate::{HarborWallet, Message, SendStatus};
 pub fn send(harbor: &HarborWallet) -> Element<Message> {
     let header = h_header("Send", "Send to an on-chain address or lightning invoice.");
 
+    // todo disable amount input if max is selected
     let amount_input = h_input(
         "Amount",
         "420",
@@ -48,6 +49,8 @@ pub fn send(harbor: &HarborWallet) -> Element<Message> {
             .color(Color::from_rgb(0., 255., 0.))
     });
 
+    let checkbox = Checkbox::new("Send Max", harbor.is_max).on_toggle(Message::SetIsMax);
+
     let column = if let Some(failure_message) = failure_message {
         let dangit_button =
             h_button("Dangit", SvgIcon::Squirrel, false).on_press(Message::SendStateReset);
@@ -56,7 +59,7 @@ pub fn send(harbor: &HarborWallet) -> Element<Message> {
         let nice_button = h_button("Nice", SvgIcon::Heart, false).on_press(Message::SendStateReset);
         column![header, success_message, nice_button]
     } else {
-        column![header, amount_input, dest_input, send_button]
+        column![header, amount_input, checkbox, dest_input, send_button]
     };
 
     container(scrollable(