diff --git a/ndn-cxx/encoding/estimator.cpp b/ndn-cxx/encoding/estimator.cpp
index bd1fc9a..5e3a31a 100644
--- a/ndn-cxx/encoding/estimator.cpp
+++ b/ndn-cxx/encoding/estimator.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2018 Regents of the University of California.
+ * Copyright (c) 2013-2021 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -25,59 +25,33 @@
 namespace encoding {
 
 size_t
-Estimator::prependVarNumber(uint64_t varNumber) const noexcept
+Estimator::prependVarNumber(uint64_t n) const noexcept
 {
-  if (varNumber < 253) {
-    return 1;
-  }
-  else if (varNumber <= std::numeric_limits<uint16_t>::max()) {
-    return 3;
-  }
-  else if (varNumber <= std::numeric_limits<uint32_t>::max()) {
-    return 5;
-  }
-  else {
-    return 9;
-  }
+  return tlv::sizeOfVarNumber(n);
 }
 
 size_t
-Estimator::appendVarNumber(uint64_t varNumber) const noexcept
+Estimator::appendVarNumber(uint64_t n) const noexcept
 {
-  return prependVarNumber(varNumber);
+  return tlv::sizeOfVarNumber(n);
 }
 
 size_t
-Estimator::prependNonNegativeInteger(uint64_t varNumber) const noexcept
+Estimator::prependNonNegativeInteger(uint64_t n) const noexcept
 {
-  if (varNumber <= std::numeric_limits<uint8_t>::max()) {
-    return 1;
-  }
-  else if (varNumber <= std::numeric_limits<uint16_t>::max()) {
-    return 2;
-  }
-  else if (varNumber <= std::numeric_limits<uint32_t>::max()) {
-    return 4;
-  }
-  else {
-    return 8;
-  }
+  return tlv::sizeOfNonNegativeInteger(n);
 }
 
 size_t
-Estimator::appendNonNegativeInteger(uint64_t varNumber) const noexcept
+Estimator::appendNonNegativeInteger(uint64_t n) const noexcept
 {
-  return prependNonNegativeInteger(varNumber);
+  return tlv::sizeOfNonNegativeInteger(n);
 }
 
 size_t
 Estimator::prependByteArrayBlock(uint32_t type, const uint8_t* array, size_t arraySize) const noexcept
 {
-  size_t totalLength = arraySize;
-  totalLength += prependVarNumber(arraySize);
-  totalLength += prependVarNumber(type);
-
-  return totalLength;
+  return tlv::sizeOfVarNumber(type) + tlv::sizeOfVarNumber(arraySize) + arraySize;
 }
 
 size_t
diff --git a/ndn-cxx/encoding/estimator.hpp b/ndn-cxx/encoding/estimator.hpp
index b5b3654..5341ccd 100644
--- a/ndn-cxx/encoding/estimator.hpp
+++ b/ndn-cxx/encoding/estimator.hpp
@@ -28,15 +28,17 @@
 namespace encoding {
 
 /**
- * @brief Helper class to estimate size of TLV encoding
- * Interface of this class (mostly) matches interface of Encoder class
+ * @brief Helper class to estimate size of TLV encoding.
+ *
+ * The interface of this class (mostly) matches that of the Encoder class.
+ *
  * @sa Encoder
  */
 class Estimator : noncopyable
 {
 public: // common interface between Encoder and Estimator
   /**
-   * @brief Prepend a byte
+   * @brief Prepend a single byte
    */
   constexpr size_t
   prependByte(uint8_t) const noexcept
@@ -45,7 +47,7 @@
   }
 
   /**
-   * @brief Append a byte
+   * @brief Append a single byte
    */
   constexpr size_t
   appendByte(uint8_t) const noexcept
@@ -72,7 +74,7 @@
   }
 
   /**
-   * @brief Prepend range of bytes from the range [@p first, @p last)
+   * @brief Prepend bytes from the range [@p first, @p last)
    */
   template<class Iterator>
   size_t
@@ -82,7 +84,7 @@
   }
 
   /**
-   * @brief Append range of bytes from the range [@p first, @p last)
+   * @brief Append bytes from the range [@p first, @p last)
    */
   template<class Iterator>
   size_t
@@ -92,32 +94,28 @@
   }
 
   /**
-   * @brief Prepend VarNumber @p varNumber of NDN TLV encoding
-   * @sa http://named-data.net/doc/ndn-tlv/
+   * @brief Prepend @p n in VarNumber encoding
    */
   size_t
-  prependVarNumber(uint64_t varNumber) const noexcept;
+  prependVarNumber(uint64_t n) const noexcept;
 
   /**
-   * @brief Prepend VarNumber @p varNumber of NDN TLV encoding
-   * @sa http://named-data.net/doc/ndn-tlv/
+   * @brief Append @p n in VarNumber encoding
    */
   size_t
-  appendVarNumber(uint64_t varNumber) const noexcept;
+  appendVarNumber(uint64_t n) const noexcept;
 
   /**
-   * @brief Prepend non-negative integer @p integer of NDN TLV encoding
-   * @sa http://named-data.net/doc/ndn-tlv/
+   * @brief Prepend @p n in NonNegativeInteger encoding
    */
   size_t
-  prependNonNegativeInteger(uint64_t integer) const noexcept;
+  prependNonNegativeInteger(uint64_t n) const noexcept;
 
   /**
-   * @brief Append non-negative integer @p integer of NDN TLV encoding
-   * @sa http://named-data.net/doc/ndn-tlv/
+   * @brief Append @p n in NonNegativeInteger encoding
    */
   size_t
-  appendNonNegativeInteger(uint64_t integer) const noexcept;
+  appendNonNegativeInteger(uint64_t n) const noexcept;
 
   /**
    * @brief Prepend TLV block of type @p type and value from buffer @p array of size @p arraySize