diff --git a/include/exiv2/exif.hpp b/include/exiv2/exif.hpp
index 347747a2..c9c1c774 100644
--- a/include/exiv2/exif.hpp
+++ b/include/exiv2/exif.hpp
@@ -168,7 +168,7 @@ namespace Exiv2 {
         //! Return the number of components in the value
         size_t count() const override;
         //! Return the size of the value in bytes
-        long size() const override;
+        size_t size() const override;
         //! Return the value as a string.
         std::string toString() const override;
         std::string toString(long n) const override;
diff --git a/include/exiv2/iptc.hpp b/include/exiv2/iptc.hpp
index a806e951..c5a1d920 100644
--- a/include/exiv2/iptc.hpp
+++ b/include/exiv2/iptc.hpp
@@ -120,7 +120,7 @@ namespace Exiv2 {
         const char* typeName() const override;
         long typeSize() const override;
         size_t count() const override;
-        long size() const override;
+        size_t size() const override;
         std::string toString() const override;
         std::string toString(long n) const override;
         int64_t toInt64(long n = 0) const override;
@@ -236,19 +236,17 @@ namespace Exiv2 {
                               uint16_t record = IptcDataSets::application2) const;
         //! Return true if there is no IPTC metadata
         bool empty() const { return count() == 0; }
+
         //! Get the number of metadata entries
-        long count() const { return static_cast<long>(iptcMetadata_.size()); }
-        /*!
-          @brief Return the exact size of all contained IPTC metadata
-         */
-        long size() const;
-        /*!
-          @brief Return the metadata charset name or 0
-         */
+        size_t count() const { return iptcMetadata_.size(); }
+
+        //! @brief Return the exact size of all contained IPTC metadata
+        size_t size() const;
+
+        //! @brief Return the metadata charset name or 0
         const char *detectCharset() const;
-        /*!
-          @brief dump iptc formatted binary data (used by printStructure kpsRecursive)
-        */
+
+        //!  @brief dump iptc formatted binary data (used by printStructure kpsRecursive)
         static void printStructure(std::ostream& out, const Slice<byte*>& bytes,uint32_t depth);
         //@}
 
diff --git a/include/exiv2/metadatum.hpp b/include/exiv2/metadatum.hpp
index bdf03b74..aad5110d 100644
--- a/include/exiv2/metadatum.hpp
+++ b/include/exiv2/metadatum.hpp
@@ -191,7 +191,7 @@ namespace Exiv2 {
         //! Return the number of components in the value
         virtual size_t count() const =0;
         //! Return the size of the value in bytes
-        virtual long size() const =0;
+        virtual size_t size() const =0;
         //! Return the value as a string.
         virtual std::string toString() const =0;
         /*!
diff --git a/include/exiv2/xmp_exiv2.hpp b/include/exiv2/xmp_exiv2.hpp
index 15f32108..c2ee9941 100644
--- a/include/exiv2/xmp_exiv2.hpp
+++ b/include/exiv2/xmp_exiv2.hpp
@@ -115,7 +115,7 @@ namespace Exiv2 {
         //! The Exif typeSize doesn't make sense here. Return 0.
         long typeSize() const override;
         size_t count() const override;
-        long size() const override;
+        size_t size() const override;
         std::string toString() const override;
         std::string toString(long n) const override;
         int64_t toInt64(long n = 0) const override;
diff --git a/src/crwimage_int.cpp b/src/crwimage_int.cpp
index e9b90c40..ea965c01 100644
--- a/src/crwimage_int.cpp
+++ b/src/crwimage_int.cpp
@@ -1019,12 +1019,14 @@ namespace Exiv2::Internal {
         const auto ed2 = image.exifData().findKey(k2);
         const auto edEnd = image.exifData().end();
 
-        long size = 0;
-        if (ed1 != edEnd) size += ed1->size();
-        if (ed2 != edEnd) size += ed2->size();
+        size_t size{0};
+        if (ed1 != edEnd)
+            size += ed1->size();
+        if (ed2 != edEnd)
+            size += ed2->size();
         if (size != 0) {
             DataBuf buf(size);
-            long pos = 0;
+            size_t pos{0};
             if (ed1 != edEnd) {
                 ed1->copy(buf.data(), pHead->byteOrder());
                 pos += ed1->size();
@@ -1039,7 +1041,7 @@ namespace Exiv2::Internal {
         else {
             pHead->remove(pCrwMapping->crwTagId_, pCrwMapping->crwDir_);
         }
-    } // CrwMap::encode0x080a
+    }
 
     void CrwMap::encodeArray(const Image&      image,
                              const CrwMapping* pCrwMapping,
diff --git a/src/exif.cpp b/src/exif.cpp
index b24cd308..412ccb20 100644
--- a/src/exif.cpp
+++ b/src/exif.cpp
@@ -318,7 +318,7 @@ namespace Exiv2 {
 
     size_t Exifdatum::count() const { return value_ ? value_->count() : 0; }
 
-    long Exifdatum::size() const { return value_ ? static_cast<long>(value_->size()) : 0; }
+    size_t Exifdatum::size() const { return value_ ? value_->size() : 0; }
 
     std::string Exifdatum::toString() const { return value_ ? value_->toString() : ""; }
 
diff --git a/src/iptc.cpp b/src/iptc.cpp
index ea87d97e..34a2d91d 100644
--- a/src/iptc.cpp
+++ b/src/iptc.cpp
@@ -114,7 +114,7 @@ namespace Exiv2 {
 
     size_t Iptcdatum::count() const { return value_ ? value_->count() : 0; }
 
-    long Iptcdatum::size() const { return value_ ? static_cast<long>(value_->size()) : 0; }
+    size_t Iptcdatum::size() const { return value_ ? value_->size() : 0; }
 
     std::string Iptcdatum::toString() const { return value_ ? value_->toString() : ""; }
 
@@ -197,13 +197,13 @@ namespace Exiv2 {
         return *pos;
     }
 
-    long IptcData::size() const
+    size_t IptcData::size() const
     {
-        long newSize = 0;
+        size_t newSize = 0;
         for (auto&& iptc : iptcMetadata_) {
             // marker, record Id, dataset num, first 2 bytes of size
             newSize += 5;
-            long dataSize = iptc.size();
+            size_t dataSize = iptc.size();
             newSize += dataSize;
             if (dataSize > 32767) {
                 // extended dataset (we always use 4 bytes)
@@ -211,7 +211,7 @@ namespace Exiv2 {
             }
         }
         return newSize;
-    } // IptcData::size
+    }
 
     int IptcData::add(const IptcKey& key, Value* value)
     {
@@ -450,13 +450,13 @@ namespace Exiv2 {
             *pWrite++ = static_cast<byte>(iter.tag());
 
             // extended or standard dataset?
-            long dataSize = iter.size();
+            size_t dataSize = iter.size();
             if (dataSize > 32767) {
                 // always use 4 bytes for extended length
                 uint16_t sizeOfSize = 4 | 0x8000;
                 us2Data(pWrite, sizeOfSize, bigEndian);
                 pWrite += 2;
-                ul2Data(pWrite, dataSize, bigEndian);
+                ul2Data(pWrite, static_cast<uint32_t>(dataSize), bigEndian);
                 pWrite += 4;
             }
             else {
diff --git a/src/tiffvisitor_int.cpp b/src/tiffvisitor_int.cpp
index c3bd125b..c15e57c1 100644
--- a/src/tiffvisitor_int.cpp
+++ b/src/tiffvisitor_int.cpp
@@ -1031,7 +1031,7 @@ namespace Exiv2::Internal {
 #ifdef EXIV2_DEBUG_MESSAGES
         bool tooLarge = false;
 #endif
-        uint32_t newSize = datum->size();
+        size_t newSize = datum->size();
         if (newSize > object->size_) { // value doesn't fit, encode for intrusive writing
             setDirty();
 #ifdef EXIV2_DEBUG_MESSAGES
@@ -1046,14 +1046,14 @@ namespace Exiv2::Internal {
             std::cerr << "\t\t\t ALLOCATED " << std::dec << object->size_ << " BYTES";
         }
 #endif
-    } // TiffEncoder::encodeTiffEntryBase
+    }
 
     void TiffEncoder::encodeOffsetEntry(TiffEntryBase* object, const Exifdatum* datum)
     {
         assert(object);
         assert(datum);
 
-        uint32_t newSize = datum->size();
+        size_t newSize = datum->size();
         if (newSize > object->size_) { // value doesn't fit, encode for intrusive writing
             setDirty();
             object->updateValue(datum->getValue(), byteOrder()); // clones the value
@@ -1071,8 +1071,7 @@ namespace Exiv2::Internal {
             std::cerr << "\t\t\t PRESERVE VALUE DATA";
 #endif
         }
-
-    } // TiffEncoder::encodeOffsetEntry
+    }
 
     void TiffEncoder::add(
         TiffComponent* pRootDir,
diff --git a/src/xmp.cpp b/src/xmp.cpp
index ff7aadb2..f96b157e 100644
--- a/src/xmp.cpp
+++ b/src/xmp.cpp
@@ -352,7 +352,7 @@ namespace Exiv2 {
 
     size_t Xmpdatum::count() const { return p_->value_ ? p_->value_->count() : 0; }
 
-    long Xmpdatum::size() const { return p_->value_ ? static_cast<long>(p_->value_->size()) : 0; }
+    size_t Xmpdatum::size() const { return p_->value_ ? p_->value_->size() : 0; }
 
     std::string Xmpdatum::toString() const { return p_->value_ ? p_->value_->toString() : ""; }