diff --git a/erpnext/accounts/doctype/pos_invoice/pos_invoice.js b/erpnext/accounts/doctype/pos_invoice/pos_invoice.js
index 181e9f8..e317546 100644
--- a/erpnext/accounts/doctype/pos_invoice/pos_invoice.js
+++ b/erpnext/accounts/doctype/pos_invoice/pos_invoice.js
@@ -111,16 +111,12 @@
 	}
 
 	write_off_outstanding_amount_automatically() {
-		if(cint(this.frm.doc.write_off_outstanding_amount_automatically)) {
+		if (cint(this.frm.doc.write_off_outstanding_amount_automatically)) {
 			frappe.model.round_floats_in(this.frm.doc, ["grand_total", "paid_amount"]);
 			// this will make outstanding amount 0
 			this.frm.set_value("write_off_amount",
 				flt(this.frm.doc.grand_total - this.frm.doc.paid_amount - this.frm.doc.total_advance, precision("write_off_amount"))
 			);
-			this.frm.toggle_enable("write_off_amount", false);
-
-		} else {
-			this.frm.toggle_enable("write_off_amount", true);
 		}
 
 		this.calculate_outstanding_amount(false);
diff --git a/erpnext/accounts/doctype/pos_invoice/pos_invoice.json b/erpnext/accounts/doctype/pos_invoice/pos_invoice.json
index fcccb39..3e22b9e 100644
--- a/erpnext/accounts/doctype/pos_invoice/pos_invoice.json
+++ b/erpnext/accounts/doctype/pos_invoice/pos_invoice.json
@@ -1183,7 +1183,8 @@
    "label": "Write Off Amount",
    "no_copy": 1,
    "options": "currency",
-   "print_hide": 1
+   "print_hide": 1,
+   "read_only_depends_on": "eval: doc.write_off_outstanding_amount_automatically"
   },
   {
    "fieldname": "base_write_off_amount",
@@ -1554,7 +1555,7 @@
  "icon": "fa fa-file-text",
  "is_submittable": 1,
  "links": [],
- "modified": "2021-08-17 20:13:44.255437",
+ "modified": "2021-08-18 16:13:52.080543",
  "modified_by": "Administrator",
  "module": "Accounts",
  "name": "POS Invoice",
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.js b/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
index 8d65101..2071827 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.js
@@ -324,16 +324,12 @@
 	}
 
 	write_off_outstanding_amount_automatically() {
-		if(cint(this.frm.doc.write_off_outstanding_amount_automatically)) {
+		if (cint(this.frm.doc.write_off_outstanding_amount_automatically)) {
 			frappe.model.round_floats_in(this.frm.doc, ["grand_total", "paid_amount"]);
 			// this will make outstanding amount 0
 			this.frm.set_value("write_off_amount",
 				flt(this.frm.doc.grand_total - this.frm.doc.paid_amount - this.frm.doc.total_advance, precision("write_off_amount"))
 			);
-			this.frm.toggle_enable("write_off_amount", false);
-
-		} else {
-			this.frm.toggle_enable("write_off_amount", true);
 		}
 
 		this.calculate_outstanding_amount(false);
@@ -787,8 +783,6 @@
 		if (frappe.boot.sysdefaults.country == 'India') unhide_field(['c_form_applicable', 'c_form_no']);
 		else hide_field(['c_form_applicable', 'c_form_no']);
 
-		frm.toggle_enable("write_off_amount", !!!cint(doc.write_off_outstanding_amount_automatically));
-
 		frm.refresh_fields();
 	},
 
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.json b/erpnext/accounts/doctype/sales_invoice/sales_invoice.json
index e317443..5023c9c 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.json
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.json
@@ -1444,7 +1444,8 @@
    "label": "Write Off Amount",
    "no_copy": 1,
    "options": "currency",
-   "print_hide": 1
+   "print_hide": 1,
+   "read_only_depends_on": "eval:doc.write_off_outstanding_amount_automatically"
   },
   {
    "fieldname": "base_write_off_amount",
@@ -2014,7 +2015,7 @@
    "link_fieldname": "consolidated_invoice"
   }
  ],
- "modified": "2021-08-17 20:16:12.737743",
+ "modified": "2021-08-18 16:07:45.122570",
  "modified_by": "Administrator",
  "module": "Accounts",
  "name": "Sales Invoice",