diff --git a/README.md b/README.md
index f34e8870..e30052dc 100644
--- a/README.md
+++ b/README.md
@@ -147,7 +147,7 @@ that might be used to customize high-order term calculation.
 
 ```c++
 BENCHMARK(BM_StringCompare)->RangeMultiplier(2)
-    ->Range(1<<10, 1<<18)->Complexity([](size_t n)->double{return n; });
+    ->Range(1<<10, 1<<18)->Complexity([](int n)->double{return n; });
 ```
 
 ### Templated benchmarks
diff --git a/include/benchmark/benchmark_api.h b/include/benchmark/benchmark_api.h
index 0cb43488..34cd0b5c 100644
--- a/include/benchmark/benchmark_api.h
+++ b/include/benchmark/benchmark_api.h
@@ -253,7 +253,7 @@ enum BigO {
 
 // BigOFunc is passed to a benchmark in order to specify the asymptotic 
 // computational complexity for the benchmark.
-typedef double(BigOFunc)(size_t);
+typedef double(BigOFunc)(int);
 
 // State is passed to a running Benchmark and contains state for the
 // benchmark to use.
diff --git a/src/complexity.cc b/src/complexity.cc
index 0d53ade0..e25aa3c4 100644
--- a/src/complexity.cc
+++ b/src/complexity.cc
@@ -29,18 +29,18 @@ namespace benchmark {
 BigOFunc* FittingCurve(BigO complexity) {
   switch (complexity) {
     case oN:
-      return [](size_t n) -> double { return n; };
+      return [](int n) -> double { return n; };
     case oNSquared:
-      return [](size_t n) -> double { return n * n; };
+      return [](int n) -> double { return n * n; };
     case oNCubed:
-      return [](size_t n) -> double { return n * n * n; };
+      return [](int n) -> double { return n * n * n; };
     case oLogN:
-      return [](size_t n) { return log2(n); };
+      return [](int n) { return log2(n); };
     case oNLogN:
-      return [](size_t n) { return n * log2(n); };
+      return [](int n) { return n * log2(n); };
     case o1:
     default:
-      return [](size_t) { return 1.0; };
+      return [](int) { return 1.0; };
   }
 }
 
diff --git a/test/complexity_test.cc b/test/complexity_test.cc
index 03bd2dcc..662b627a 100644
--- a/test/complexity_test.cc
+++ b/test/complexity_test.cc
@@ -154,7 +154,7 @@ void BM_Complexity_O1(benchmark::State& state) {
   state.SetComplexityN(state.range_x());
 }
 BENCHMARK(BM_Complexity_O1) -> Range(1, 1<<18) -> Complexity(benchmark::o1);
-BENCHMARK(BM_Complexity_O1) -> Range(1, 1<<18) -> Complexity([](size_t){return 1.0; });
+BENCHMARK(BM_Complexity_O1) -> Range(1, 1<<18) -> Complexity([](int){return 1.0; });
 BENCHMARK(BM_Complexity_O1) -> Range(1, 1<<18) -> Complexity();
 
 std::string big_o_1_test_name = "BM_Complexity_O1_BigO";
@@ -192,7 +192,7 @@ void BM_Complexity_O_N(benchmark::State& state) {
   state.SetComplexityN(state.range_x());
 }
 BENCHMARK(BM_Complexity_O_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity(benchmark::oN);
-BENCHMARK(BM_Complexity_O_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity([](size_t n) -> double{return n; });
+BENCHMARK(BM_Complexity_O_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity([](int n) -> double{return n; });
 BENCHMARK(BM_Complexity_O_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity();
 
 std::string big_o_n_test_name = "BM_Complexity_O_N_BigO";
@@ -220,7 +220,7 @@ static void BM_Complexity_O_N_log_N(benchmark::State& state) {
   state.SetComplexityN(state.range_x());
 }
 BENCHMARK(BM_Complexity_O_N_log_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity(benchmark::oNLogN);
-BENCHMARK(BM_Complexity_O_N_log_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity([](size_t n) {return n * log2(n); });
+BENCHMARK(BM_Complexity_O_N_log_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity([](int n) {return n * log2(n); });
 BENCHMARK(BM_Complexity_O_N_log_N) -> RangeMultiplier(2) -> Range(1<<10, 1<<16) -> Complexity();
 
 std::string big_o_n_lg_n_test_name = "BM_Complexity_O_N_log_N_BigO";