diff --git a/delta_performer.cc b/delta_performer.cc
index 81477de..0c06c8b 100644
--- a/delta_performer.cc
+++ b/delta_performer.cc
@@ -128,12 +128,12 @@
   string total_operations_str("?");
   string completed_percentage_str("");
   if (num_total_operations_) {
-    total_operations_str = base::StringPrintf("%zu", num_total_operations_);
+    total_operations_str = std::to_string(num_total_operations_);
     // Upcasting to 64-bit to avoid overflow, back to size_t for formatting.
     completed_percentage_str =
         base::StringPrintf(" (%" PRIu64 "%%)",
-                     IntRatio(next_operation_num_, num_total_operations_,
-                              100));
+                           IntRatio(next_operation_num_, num_total_operations_,
+                                    100));
   }
 
   // Format download total count and percentage.
@@ -141,11 +141,11 @@
   string payload_size_str("?");
   string downloaded_percentage_str("");
   if (payload_size) {
-    payload_size_str = base::StringPrintf("%zu", payload_size);
+    payload_size_str = std::to_string(payload_size);
     // Upcasting to 64-bit to avoid overflow, back to size_t for formatting.
     downloaded_percentage_str =
         base::StringPrintf(" (%" PRIu64 "%%)",
-                     IntRatio(total_bytes_received_, payload_size, 100));
+                           IntRatio(total_bytes_received_, payload_size, 100));
   }
 
   LOG(INFO) << (message_prefix ? message_prefix : "") << next_operation_num_
diff --git a/fake_p2p_manager_configuration.h b/fake_p2p_manager_configuration.h
index 1dc7c6e..806206c 100644
--- a/fake_p2p_manager_configuration.h
+++ b/fake_p2p_manager_configuration.h
@@ -47,7 +47,7 @@
                                             size_t minimum_size) override {
     std::vector<std::string> formatted_command = p2p_client_cmd_format_;
     // Replace {variable} on the passed string.
-    std::string str_minimum_size = base::SizeTToString(minimum_size);
+    std::string str_minimum_size = std::to_string(minimum_size);
     for (std::string& arg : formatted_command) {
       ReplaceSubstringsAfterOffset(&arg, 0, "{file_id}", file_id);
       ReplaceSubstringsAfterOffset(&arg, 0, "{minsize}", str_minimum_size);
diff --git a/libcurl_http_fetcher.cc b/libcurl_http_fetcher.cc
index 9d32293..8010b8c 100644
--- a/libcurl_http_fetcher.cc
+++ b/libcurl_http_fetcher.cc
@@ -8,6 +8,7 @@
 #include <string>
 
 #include <base/bind.h>
+#include <base/format_macros.h>
 #include <base/location.h>
 #include <base/logging.h>
 #include <base/strings/string_util.h>
@@ -132,10 +133,10 @@
     }
 
     // Create a string representation of the desired range.
-    string range_str = (end_offset ?
-                        base::StringPrintf("%jd-%zu", resume_offset_,
-                                           end_offset) :
-                        base::StringPrintf("%jd-", resume_offset_));
+    string range_str = base::StringPrintf(
+        "%" PRIu64 "-", static_cast<uint64_t>(resume_offset_));
+    if (end_offset)
+      range_str += std::to_string(end_offset);
     CHECK_EQ(curl_easy_setopt(curl_handle_, CURLOPT_RANGE, range_str.c_str()),
              CURLE_OK);
   }
diff --git a/multi_range_http_fetcher.cc b/multi_range_http_fetcher.cc
index 07118a3..8d1fd06 100644
--- a/multi_range_http_fetcher.cc
+++ b/multi_range_http_fetcher.cc
@@ -169,9 +169,9 @@
 std::string MultiRangeHttpFetcher::Range::ToString() const {
   std::string range_str = base::StringPrintf("%jd+", offset());
   if (HasLength())
-    base::StringAppendF(&range_str, "%zu", length());
+    range_str += std::to_string(length());
   else
-    base::StringAppendF(&range_str, "?");
+    range_str += "?";
   return range_str;
 }
 
diff --git a/p2p_manager.cc b/p2p_manager.cc
index daebe91..9b6a659 100644
--- a/p2p_manager.cc
+++ b/p2p_manager.cc
@@ -30,6 +30,7 @@
 #include <base/bind.h>
 #include <base/files/file_enumerator.h>
 #include <base/files/file_path.h>
+#include <base/format_macros.h>
 #include <base/logging.h>
 #include <base/strings/string_util.h>
 #include <base/strings/stringprintf.h>
@@ -90,7 +91,7 @@
     vector<string> args;
     args.push_back("p2p-client");
     args.push_back(string("--get-url=") + file_id);
-    args.push_back(StringPrintf("--minimum-size=%zu", minimum_size));
+    args.push_back(StringPrintf("--minimum-size=%" PRIuS, minimum_size));
     return args;
   }
 
@@ -553,7 +554,7 @@
       }
     }
 
-    string decimal_size = StringPrintf("%zu", expected_size);
+    string decimal_size = std::to_string(expected_size);
     if (fsetxattr(fd, kCrosP2PFileSizeXAttrName,
                   decimal_size.c_str(), decimal_size.size(), 0) != 0) {
       PLOG(ERROR) << "Error setting xattr " << path.value();
diff --git a/p2p_manager_unittest.cc b/p2p_manager_unittest.cc
index 18b4184..7e3f57f 100644
--- a/p2p_manager_unittest.cc
+++ b/p2p_manager_unittest.cc
@@ -312,7 +312,7 @@
   }
 
   if (size_xattr != 0) {
-    string decimal_size = base::StringPrintf("%zu", size_xattr);
+    string decimal_size = std::to_string(size_xattr);
     if (fsetxattr(fd, "user.cros-p2p-filesize",
                   decimal_size.c_str(), decimal_size.size(), 0) != 0) {
       PLOG(ERROR) << "Error setting xattr on " << path;
diff --git a/test_utils.cc b/test_utils.cc
index b4a8074..7965f85 100644
--- a/test_utils.cc
+++ b/test_utils.cc
@@ -18,6 +18,7 @@
 #include <vector>
 
 #include <base/files/file_util.h>
+#include <base/format_macros.h>
 #include <base/logging.h>
 #include <base/strings/string_util.h>
 #include <base/strings/stringprintf.h>
@@ -168,7 +169,7 @@
                                size_t size,
                                int block_size) {
   EXPECT_EQ(0, System(StringPrintf("dd if=/dev/zero of=%s"
-                                   " seek=%zu bs=1 count=1 status=none",
+                                   " seek=%" PRIuS " bs=1 count=1 status=none",
                                    path.c_str(), size)));
   EXPECT_EQ(0, System(StringPrintf("mkfs.ext3 -q -b %d -F %s",
                                    block_size, path.c_str())));
diff --git a/utils.cc b/utils.cc
index 7777fca..1366a39 100644
--- a/utils.cc
+++ b/utils.cc
@@ -29,6 +29,7 @@
 #include <base/files/file_path.h>
 #include <base/files/file_util.h>
 #include <base/files/scoped_file.h>
+#include <base/format_macros.h>
 #include <base/location.h>
 #include <base/logging.h>
 #include <base/posix/eintr_wrapper.h>
@@ -1518,7 +1519,7 @@
 
 string CalculateP2PFileId(const string& payload_hash, size_t payload_size) {
   string encoded_hash = chromeos::data_encoding::Base64Encode(payload_hash);
-  return base::StringPrintf("cros_update_size_%zu_hash_%s",
+  return base::StringPrintf("cros_update_size_%" PRIuS "_hash_%s",
                             payload_size,
                             encoded_hash.c_str());
 }