diff --git a/index.js b/index.js
index 982ea1e..5ac5606 100644
--- a/index.js
+++ b/index.js
@@ -23,6 +23,11 @@ const crypto = require("crypto")
 const app = express();
 const port = process.env.SERVER_PORT || 3000;
 
+const invalidBlocks = [
+	// Emergency number prefixes (112, 911, 999, 110, 117, 119, 113, 191, 111)
+	1120000, 9110000, 9990000, 1100000, 1170000, 1190000, 1130000, 1910000, 1110000
+]
+
 const pool = mariadb.createPool({
 	host: process.env.DB_HOST || '127.0.0.1',
 	port: process.env.DB_PORT || 3306,
@@ -614,10 +619,6 @@ app.get("/api/v1/directory", (req, res) => {
 
 // Function to find open number blocks
 app.get("/api/v1/directory/openBlocks", (req, res) => {
-	const invalidBlocks = [
-		// Emergency number prefixes (112, 911, 999, 110, 117, 119, 113, 191, 111)
-		1120000, 9110000, 9990000, 1100000, 1170000, 1190000, 1130000, 1910000, 1110000
-	]
 	pool.query("SELECT block_start, block_length FROM routes").then((rows) => {
 		console.log(JSON.stringify(rows)); // for testing
 
@@ -702,8 +703,10 @@ app.get("/footer", (req, res) => {
 app.get("/api/v1/checkAvailability/:number", (req, res) => {
 	// Check if the number is 7 digits
 	const number = Number(req.params.number);
-	if (number < 2000000 || number > 9999999) {
-		res.status(400).json({ error: `Number is outside valid range` });
+	// Round to nearest 10000 so it's always NXX0000
+	number = Math.floor(number / 10000) * 10000;
+	if (!number || number < 1000000 || number > 9999999 || invalidBlocks.includes(number)) {
+		res.status(400).json({ error: `Number is outside valid range or is an invalid block` });
 		return;
 	}
 	pool.getConnection().then(conn => {