diff --git a/include/rapidjson/encodedstream.h b/include/rapidjson/encodedstream.h
index 9a93b38..7bc6ad3 100644
--- a/include/rapidjson/encodedstream.h
+++ b/include/rapidjson/encodedstream.h
@@ -146,7 +146,7 @@ private:
         if (!c)
             return;
 
-        unsigned bom = c[0] | (c[1] << 8) | (c[2] << 16) | (c[3] << 24);
+        unsigned bom = static_cast<unsigned>(c[0] | (c[1] << 8) | (c[2] << 16) | (c[3] << 24));
         hasBOM_ = false;
         if (bom == 0xFFFE0000)                  { type_ = kUTF32BE; hasBOM_ = true; is_->Take(); is_->Take(); is_->Take(); is_->Take(); }
         else if (bom == 0x0000FEFF)             { type_ = kUTF32LE; hasBOM_ = true; is_->Take(); is_->Take(); is_->Take(); is_->Take(); }
diff --git a/include/rapidjson/internal/biginteger.h b/include/rapidjson/internal/biginteger.h
index 99a30ac..d1732a0 100755
--- a/include/rapidjson/internal/biginteger.h
+++ b/include/rapidjson/internal/biginteger.h
@@ -230,7 +230,7 @@ private:
         uint64_t r = 0;
         for (const char* p = begin; p != end; ++p) {
             RAPIDJSON_ASSERT(*p >= '0' && *p <= '9');
-            r = r * 10 + (*p - '0');
+            r = r * 10u + (unsigned)(*p - '0');
         }
         return r;
     }
diff --git a/include/rapidjson/internal/diyfp.h b/include/rapidjson/internal/diyfp.h
index 3b6c423..42d8b3b 100644
--- a/include/rapidjson/internal/diyfp.h
+++ b/include/rapidjson/internal/diyfp.h
@@ -232,8 +232,8 @@ inline DiyFp GetCachedPower(int e, int* K) {
 }
 
 inline DiyFp GetCachedPower10(int exp, int *outExp) {
-     unsigned index = (exp + 348) / 8;
-     *outExp = -348 + index * 8;
+     unsigned index = (static_cast<unsigned>(exp) + 348u) / 8u;
+     *outExp = -348 + static_cast<int>(index) * 8;
      return GetCachedPowerByIndex(index);
  }
 
diff --git a/include/rapidjson/internal/dtoa.h b/include/rapidjson/internal/dtoa.h
index 2d8d2e4..3695866 100644
--- a/include/rapidjson/internal/dtoa.h
+++ b/include/rapidjson/internal/dtoa.h
@@ -62,7 +62,7 @@ inline void DigitGen(const DiyFp& W, const DiyFp& Mp, uint64_t delta, char* buff
     const DiyFp wp_w = Mp - W;
     uint32_t p1 = static_cast<uint32_t>(Mp.f >> -one.e);
     uint64_t p2 = Mp.f & (one.f - 1);
-    int kappa = CountDecimalDigit32(p1); // kappa in [0, 9]
+    unsigned kappa = CountDecimalDigit32(p1); // kappa in [0, 9]
     *len = 0;
 
     while (kappa > 0) {
@@ -158,14 +158,14 @@ inline char* Prettify(char* buffer, int length, int k) {
     }
     else if (0 < kk && kk <= 21) {
         // 1234e-2 -> 12.34
-        std::memmove(&buffer[kk + 1], &buffer[kk], length - kk);
+        std::memmove(&buffer[kk + 1], &buffer[kk], static_cast<size_t>(length - kk));
         buffer[kk] = '.';
         return &buffer[length + 1];
     }
     else if (-6 < kk && kk <= 0) {
         // 1234e-6 -> 0.001234
         const int offset = 2 - kk;
-        std::memmove(&buffer[offset], &buffer[0], length);
+        std::memmove(&buffer[offset], &buffer[0], static_cast<size_t>(length));
         buffer[0] = '0';
         buffer[1] = '.';
         for (int i = 2; i < offset; i++)
@@ -179,7 +179,7 @@ inline char* Prettify(char* buffer, int length, int k) {
     }
     else {
         // 1234e30 -> 1.234e33
-        std::memmove(&buffer[2], &buffer[1], length - 1);
+        std::memmove(&buffer[2], &buffer[1], static_cast<size_t>(length - 1));
         buffer[1] = '.';
         buffer[length + 1] = 'e';
         return WriteExponent(kk - 1, &buffer[0 + length + 2]);
diff --git a/include/rapidjson/internal/ieee754.h b/include/rapidjson/internal/ieee754.h
index e3f0336..2fdaf54 100644
--- a/include/rapidjson/internal/ieee754.h
+++ b/include/rapidjson/internal/ieee754.h
@@ -53,7 +53,7 @@ public:
         else if (order <= -1074)
             return 0;
         else
-            return order + 1074;
+            return (unsigned)order + 1074;
     }
 
 private:
diff --git a/include/rapidjson/internal/strtod.h b/include/rapidjson/internal/strtod.h
index ace65f6..a1b8211 100644
--- a/include/rapidjson/internal/strtod.h
+++ b/include/rapidjson/internal/strtod.h
@@ -95,13 +95,13 @@ inline int CheckWithinHalfULP(double b, const BigInteger& d, int dExp) {
     hS_Exp2 -= common_Exp2;
 
     BigInteger dS = d;
-    dS.MultiplyPow5(dS_Exp5) <<= dS_Exp2;
+    dS.MultiplyPow5(static_cast<unsigned>(dS_Exp5)) <<= static_cast<unsigned>(dS_Exp2);
 
     BigInteger bS(bInt);
-    bS.MultiplyPow5(bS_Exp5) <<= bS_Exp2;
+    bS.MultiplyPow5(static_cast<unsigned>(bS_Exp5)) <<= static_cast<unsigned>(bS_Exp2);
 
     BigInteger hS(1);
-    hS.MultiplyPow5(hS_Exp5) <<= hS_Exp2;
+    hS.MultiplyPow5(static_cast<unsigned>(hS_Exp5)) <<= static_cast<unsigned>(hS_Exp2);
 
     BigInteger delta(0);
     dS.Difference(bS, &delta);
@@ -134,7 +134,7 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit
         if (significand  >  RAPIDJSON_UINT64_C2(0x19999999, 0x99999999) ||
             (significand == RAPIDJSON_UINT64_C2(0x19999999, 0x99999999) && decimals[i] > '5'))
             break;
-        significand = significand * 10 + (decimals[i] - '0');
+        significand = significand * 10u + static_cast<unsigned>(decimals[i] - '0');
     }
     
     if (i < length && decimals[i] >= '5') // Rounding
@@ -163,10 +163,10 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit
             DiyFp(RAPIDJSON_UINT64_C2(0xf4240000, 00000000), -44),  // 10^6
             DiyFp(RAPIDJSON_UINT64_C2(0x98968000, 00000000), -40)   // 10^7
         };
-        int adjustment = dExp - actualExp - 1;
+        int  adjustment = dExp - actualExp - 1;
         RAPIDJSON_ASSERT(adjustment >= 0 && adjustment < 7);
         v = v * kPow10[adjustment];
-        if (length + adjustment > 19) // has more digits than decimal digits in 64-bit
+        if (length + static_cast<unsigned>(adjustment)> 19u) // has more digits than decimal digits in 64-bit
             error += kUlp / 2;
     }
 
@@ -184,14 +184,14 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit
         unsigned scaleExp = (precisionSize + kUlpShift) - 63;
         v.f >>= scaleExp;
         v.e += scaleExp; 
-        error = (error >> scaleExp) + 1 + kUlp;
+        error = (error >> scaleExp) + 1 + static_cast<int>(kUlp);
         precisionSize -= scaleExp;
     }
 
-    DiyFp rounded(v.f >> precisionSize, v.e + precisionSize);
+    DiyFp rounded(v.f >> precisionSize, v.e + static_cast<int>(precisionSize));
     const uint64_t precisionBits = (v.f & ((uint64_t(1) << precisionSize) - 1)) * kUlp;
     const uint64_t halfWay = (uint64_t(1) << (precisionSize - 1)) * kUlp;
-    if (precisionBits >= halfWay + error) {
+    if (precisionBits >= halfWay + static_cast<unsigned>(error)) {
         rounded.f++;
         if (rounded.f & (DiyFp::kDpHiddenBit << 1)) { // rounding overflows mantissa (issue #340)
             rounded.f >>= 1;
@@ -201,7 +201,7 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit
 
     *result = rounded.ToDouble();
 
-    return halfWay - error >= precisionBits || precisionBits >= halfWay + error;
+    return halfWay - static_cast<unsigned>(error) >= precisionBits || precisionBits >= halfWay + static_cast<unsigned>(error);
 }
 
 inline double StrtodBigInteger(double approx, const char* decimals, size_t length, size_t decimalPosition, int exp) {
@@ -249,7 +249,7 @@ inline double StrtodFullPrecision(double d, int p, const char* decimals, size_t
     if ((int)length > kMaxDecimalDigit) {
         int delta = (int(length) - kMaxDecimalDigit);
         exp += delta;
-        decimalPosition -= delta;
+        decimalPosition -= static_cast<unsigned>(delta);
         length = kMaxDecimalDigit;
     }
 
diff --git a/include/rapidjson/writer.h b/include/rapidjson/writer.h
index 40cdb35..8fcffbe 100644
--- a/include/rapidjson/writer.h
+++ b/include/rapidjson/writer.h
@@ -350,7 +350,7 @@ template<>
 inline bool Writer<StringBuffer>::WriteInt(int i) {
     char *buffer = os_->Push(11);
     const char* end = internal::i32toa(i, buffer);
-    os_->Pop(11 - (end - buffer));
+    os_->Pop(static_cast<size_t>(11 - (end - buffer)));
     return true;
 }
 
@@ -358,7 +358,7 @@ template<>
 inline bool Writer<StringBuffer>::WriteUint(unsigned u) {
     char *buffer = os_->Push(10);
     const char* end = internal::u32toa(u, buffer);
-    os_->Pop(10 - (end - buffer));
+    os_->Pop(static_cast<size_t>(10 - (end - buffer)));
     return true;
 }
 
@@ -366,7 +366,7 @@ template<>
 inline bool Writer<StringBuffer>::WriteInt64(int64_t i64) {
     char *buffer = os_->Push(21);
     const char* end = internal::i64toa(i64, buffer);
-    os_->Pop(21 - (end - buffer));
+    os_->Pop(static_cast<size_t>(21 - (end - buffer)));
     return true;
 }
 
@@ -374,7 +374,7 @@ template<>
 inline bool Writer<StringBuffer>::WriteUint64(uint64_t u) {
     char *buffer = os_->Push(20);
     const char* end = internal::u64toa(u, buffer);
-    os_->Pop(20 - (end - buffer));
+    os_->Pop(static_cast<size_t>(20 - (end - buffer)));
     return true;
 }
 
@@ -382,7 +382,7 @@ template<>
 inline bool Writer<StringBuffer>::WriteDouble(double d) {
     char *buffer = os_->Push(25);
     char* end = internal::dtoa(d, buffer);
-    os_->Pop(25 - (end - buffer));
+    os_->Pop(static_cast<size_t>(25 - (end - buffer)));
     return true;
 }