diff --git a/src/node_http2.cc b/src/node_http2.cc
index 11698d177ad082..7904c680b89369 100644
--- a/src/node_http2.cc
+++ b/src/node_http2.cc
@@ -382,7 +382,7 @@ Headers::Headers(Isolate* isolate,
                                  header_string_len);
   // Make sure the start address is aligned appropriately for an nghttp2_nv*.
   char* start = reinterpret_cast<char*>(
-      ROUND_UP(reinterpret_cast<uintptr_t>(*buf_), alignof(nghttp2_nv)));
+      RoundUp(reinterpret_cast<uintptr_t>(*buf_), alignof(nghttp2_nv)));
   char* header_contents = start + (count_ * sizeof(nghttp2_nv));
   nghttp2_nv* const nva = reinterpret_cast<nghttp2_nv*>(start);
 
@@ -438,8 +438,8 @@ Origins::Origins(Isolate* isolate,
 
   // Make sure the start address is aligned appropriately for an nghttp2_nv*.
   char* start = reinterpret_cast<char*>(
-      ROUND_UP(reinterpret_cast<uintptr_t>(*buf_),
-               alignof(nghttp2_origin_entry)));
+      RoundUp(reinterpret_cast<uintptr_t>(*buf_),
+              alignof(nghttp2_origin_entry)));
   char* origin_contents = start + (count_ * sizeof(nghttp2_origin_entry));
   nghttp2_origin_entry* const nva =
       reinterpret_cast<nghttp2_origin_entry*>(start);
diff --git a/src/spawn_sync.cc b/src/spawn_sync.cc
index 962fafa91f30b5..0dbf5f09fc78bf 100644
--- a/src/spawn_sync.cc
+++ b/src/spawn_sync.cc
@@ -1049,7 +1049,7 @@ Maybe<int> SyncProcessRunner::CopyJsStringArray(Local<Value> js_value,
     Maybe<size_t> maybe_size = StringBytes::StorageSize(isolate, value, UTF8);
     if (maybe_size.IsNothing()) return Nothing<int>();
     data_size += maybe_size.FromJust() + 1;
-    data_size = ROUND_UP(data_size, sizeof(void*));
+    data_size = RoundUp(data_size, sizeof(void*));
   }
 
   buffer = new char[list_size + data_size];
@@ -1066,7 +1066,7 @@ Maybe<int> SyncProcessRunner::CopyJsStringArray(Local<Value> js_value,
                                       value,
                                       UTF8);
     buffer[data_offset++] = '\0';
-    data_offset = ROUND_UP(data_offset, sizeof(void*));
+    data_offset = RoundUp(data_offset, sizeof(void*));
   }
 
   list[length] = nullptr;
diff --git a/src/util.h b/src/util.h
index ea705b800bdf17..f3a174821ab882 100644
--- a/src/util.h
+++ b/src/util.h
@@ -617,9 +617,11 @@ constexpr size_t arraysize(const T (&)[N]) {
   return N;
 }
 
-#ifndef ROUND_UP
-#define ROUND_UP(a, b) ((a) % (b) ? ((a) + (b)) - ((a) % (b)) : (a))
-#endif
+// Round up a to the next highest multiple of b.
+template <typename T>
+constexpr T RoundUp(T a, T b) {
+  return a % b != 0 ? a + b - (a % b) : a;
+}
 
 #ifdef __GNUC__
 #define MUST_USE_RESULT __attribute__((warn_unused_result))