diff --git a/ports/webassembly/wrapper.js b/ports/webassembly/wrapper.js
index dcbfe6c017..24f4f8a72c 100644
--- a/ports/webassembly/wrapper.js
+++ b/ports/webassembly/wrapper.js
@@ -37,18 +37,18 @@ var mainProgram = function()
 
   if (typeof window === 'undefined' && require.main === module) {
       var fs = require('fs');
-      var stack_size = 64 * 1024;
+      var heap_size = 128 * 1024;
       var contents = '';
       var repl = true;
 
       for (var i = 0; i < process.argv.length; i++) {
           if (process.argv[i] === '-X' && i < process.argv.length - 1) {
-              if (process.argv[i + 1].includes('stack=')) {
-                  stack_size = parseInt(process.argv[i + 1].split('stack=')[1]);
+              if (process.argv[i + 1].includes('heapsize=')) {
+                  heap_size = parseInt(process.argv[i + 1].split('heapsize=')[1]);
                   if (process.argv[i + 1].substr(-1).toLowerCase() === 'k') {
-                      stack_size *= 1024;
+                      heap_size *= 1024;
                   } else if (process.argv[i + 1].substr(-1).toLowerCase() === 'm') {
-                      stack_size *= 1024 * 1024;
+                      heap_size *= 1024 * 1024;
                   }
               }
           } else if (process.argv[i].includes('.py')) {
@@ -56,7 +56,7 @@ var mainProgram = function()
               repl = false;;
           }
       }
-      mp_js_init(stack_size);
+      mp_js_init(heap_size);
 
       if (repl) {
           mp_js_init_repl();