diff --git a/lib/evmone/instructions.hpp b/lib/evmone/instructions.hpp
index 6d16508c9f..07c59a7f3c 100644
--- a/lib/evmone/instructions.hpp
+++ b/lib/evmone/instructions.hpp
@@ -60,7 +60,8 @@ constexpr auto word_size = 32;
 /// i.e. it rounds up the number bytes to number of words.
 inline constexpr int64_t num_words(uint64_t size_in_bytes) noexcept
 {
-    return static_cast<int64_t>((size_in_bytes + (word_size - 1)) / word_size);
+    return static_cast<int64_t>(
+        size_in_bytes / word_size + static_cast<uint64_t>(size_in_bytes % word_size != 0));
 }
 
 /// Computes gas cost of copying the given amount of bytes to/from EVM memory.
diff --git a/test/state/precompiles.cpp b/test/state/precompiles.cpp
index 21b010f81e..e7e70d069b 100644
--- a/test/state/precompiles.cpp
+++ b/test/state/precompiles.cpp
@@ -32,7 +32,7 @@ constexpr auto GasCostMax = std::numeric_limits<int64_t>::max();
 
 inline constexpr int64_t num_words(size_t size_in_bytes) noexcept
 {
-    return static_cast<int64_t>((size_in_bytes + 31) / 32);
+    return static_cast<int64_t>(size_in_bytes / 32 + static_cast<size_t>(size_in_bytes % 32 != 0));
 }
 
 template <int BaseCost, int WordCost>
diff --git a/test/state/state.cpp b/test/state/state.cpp
index cdf159739d..26c9e0a86e 100644
--- a/test/state/state.cpp
+++ b/test/state/state.cpp
@@ -20,7 +20,7 @@ constexpr auto MAX_INITCODE_COUNT = 256;
 
 inline constexpr int64_t num_words(size_t size_in_bytes) noexcept
 {
-    return static_cast<int64_t>((size_in_bytes + 31) / 32);
+    return static_cast<int64_t>(size_in_bytes / 32 + static_cast<size_t>(size_in_bytes % 32 != 0));
 }
 
 int64_t compute_tx_data_cost(evmc_revision rev, bytes_view data) noexcept
diff --git a/test/unittests/instructions_test.cpp b/test/unittests/instructions_test.cpp
index c0c00e72bb..774be3ae71 100644
--- a/test/unittests/instructions_test.cpp
+++ b/test/unittests/instructions_test.cpp
@@ -204,3 +204,18 @@ TEST(instructions, compare_with_evmc_instruction_names)
         EXPECT_STREQ(instr::traits[i].name, evmc_tbl[i]);
     }
 }
+
+
+TEST(instructions, num_words)
+{
+    EXPECT_EQ(num_words(0), 0);
+    EXPECT_EQ(num_words(1), 1);
+    EXPECT_EQ(num_words(31), 1);
+    EXPECT_EQ(num_words(32), 1);
+    EXPECT_EQ(num_words(33), 2);
+    EXPECT_EQ(num_words(0xFFFFFFFFFFFFFFDF), 0x7FFFFFFFFFFFFFF);
+    EXPECT_EQ(num_words(0xFFFFFFFFFFFFFFE0), 0x7FFFFFFFFFFFFFF);
+    EXPECT_EQ(num_words(0xFFFFFFFFFFFFFFE1), 0x800000000000000);
+    EXPECT_EQ(num_words(0xFFFFFFFFFFFFFFFE), 0x800000000000000);
+    EXPECT_EQ(num_words(0xFFFFFFFFFFFFFFFF), 0x800000000000000);
+}