diff --git a/Tools/TimePlot.hs b/Tools/TimePlot.hs
--- a/Tools/TimePlot.hs
+++ b/Tools/TimePlot.hs
@@ -81,6 +81,8 @@
   "             -if IFILE [-tf TF] ",
   "             [{+|-}k Pat1 '[+Suf1] Kind1' {+|-}k Pat2 '[+Suf2] Kind2' ...] [{+|-}dk '[+Suf] KindN']",
   "             [-fromTime TIME] [-toTime TIME] [-baseTime TIME]",
+  "  --version  - show version information",
+  "  --help     - show this help",
   "  -o  OFILE  - output file",
   "  -of        - output format (default: extension of -o)",
   "  -or        - output resolution (default 640x480)",
@@ -96,6 +98,7 @@
   "               We also support %OS for fractional seconds (i.e. %OS will",
   "               parse 12.4039 or 12,4039) and %^[+-][N]s for ten-powers ",
   "               of seconds since epoch, for example %^-3s is ms since epoch.",
+  "               -tf elapsed means times are fractional seconds since an unknown moment.",
   "               Default: 'date %Y-%m-%d %H:%M:%OS'",
   "  {+|-}dk    - set default diagram kind",
   "  {+|-}k P K - set diagram kind for tracks matching regex P (in the format",
diff --git a/Tools/TimePlot/Conf.hs b/Tools/TimePlot/Conf.hs
--- a/Tools/TimePlot/Conf.hs
+++ b/Tools/TimePlot/Conf.hs
@@ -13,6 +13,7 @@
 import Graphics.Rendering.Chart
 import qualified Data.ByteString.Char8 as S
 import qualified Data.ByteString.Lazy.Char8 as B
+import Data.ByteString.Lex.Lazy.Double
 
 import Unsafe.Coerce
 
@@ -41,11 +42,17 @@
 readConf :: [String] -> Conf
 readConf args = readConf' parseTime 
   where
-    pattern = case (words $ single "time format" "-tf" ("date %Y-%m-%d %H:%M:%OS")) of
+    pattern = case (words $ single "time format" "-tf" ("%Y-%m-%d %H:%M:%OS")) of
         "date":f -> B.pack (unwords f)
-        _        -> error "Unrecognized time format (-tf)"
+        f        -> B.pack (unwords f)
     {-# NOINLINE ourStrptime #-}
-    ourStrptime = strptime pattern
+    Just (ourBaseTime,_) = strptime "%Y-%m-%d %H:%M:%OS" "1900-01-01 00:00:00" 
+    ourStrptime :: B.ByteString -> Maybe (LocalTime, B.ByteString)
+    ourStrptime = if pattern == B.pack "elapsed" 
+                    then \s -> do
+                      (d, s') <- readDouble s
+                      return (fromSeconds d ourBaseTime `add` ourBaseTime, s')
+                    else strptime pattern
     parseTime s = ourStrptime s
 
     int2double = fromIntegral :: Int -> Double
@@ -85,7 +92,9 @@
 
         fromTime    = fst `fmap` (parseTime . B.pack $ single "minimum time (inclusive)" "-fromTime" "")
         toTime      = fst `fmap` (parseTime . B.pack $ single "maximum time (exclusive)" "-toTime"   "")
-        baseTime    = fst `fmap` (parseTime . B.pack $ single "base time"                "-baseTime" "")
+        baseTime    = if pattern == B.pack "elapsed"
+                        then Just ourBaseTime
+                        else (fst `fmap` (parseTime . B.pack $ single "base time"                "-baseTime" ""))
 
         transformLabel t s = case baseTime of
           Nothing -> s
diff --git a/timeplot.cabal b/timeplot.cabal
--- a/timeplot.cabal
+++ b/timeplot.cabal
@@ -1,5 +1,5 @@
 name: timeplot
-version: 1.0.11
+version: 1.0.13
 cabal-version: >=1.6
 build-type: Simple
 license: BSD3