diff --git a/src/commands/CmdBurndown.cpp b/src/commands/CmdBurndown.cpp
index 9804e503e..481b267a7 100644
--- a/src/commands/CmdBurndown.cpp
+++ b/src/commands/CmdBurndown.cpp
@@ -27,6 +27,7 @@
 #include <cmake.h>
 #include <sstream>
 #include <algorithm>
+#include <limits>
 #include <string.h>
 #include <math.h>
 #include <Context.h>
@@ -158,6 +159,8 @@ private:
   void maxima ();
   void yLabels (std::vector <int>&);
   void calculateRates (std::vector <time_t>&);
+  unsigned round_up_to (unsigned, unsigned);
+  unsigned burndown_size (unsigned);
 
 public:
   int _width;                     // Terminal width
@@ -964,6 +967,50 @@ void Chart::calculateRates (std::vector <time_t>& sequence)
   }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+unsigned Chart::round_up_to (unsigned n, unsigned target)
+{
+  return n + target - (n % target);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+unsigned Chart::burndown_size (unsigned ntasks)
+{
+  // Nearest 2
+  if (ntasks < 20)
+    return round_up_to (ntasks, 2);
+
+  // Nearest 10
+  if (ntasks < 50)
+    return round_up_to (ntasks, 10);
+
+  // Nearest 20
+  if (ntasks < 100)
+    return round_up_to (ntasks, 20);
+
+  // Choose the number from here rounded up to the nearest 10% of the next
+  // highest power of 10 or half of power of 10.
+  const unsigned count = (unsigned) log10 (std::numeric_limits<unsigned>::max ());
+  unsigned half = 500;
+  unsigned full = 1000;
+
+  // We start at two because we handle 5, 10, 50, and 100 above.
+  for (unsigned i = 2; i < count; ++i)
+  {
+    if (ntasks < half)
+      return round_up_to (ntasks, half / 10);
+
+    if (ntasks < full)
+      return round_up_to (ntasks, full / 10);
+
+    half *= 10;
+    full *= 10;
+  }
+
+  // Round up to max of unsigned.
+  return std::numeric_limits<unsigned>::max ();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 CmdBurndownMonthly::CmdBurndownMonthly ()
 {