diff --git a/SIMULATOR.md b/SIMULATOR.md
index d695a24c..7ea1cbb8 100644
--- a/SIMULATOR.md
+++ b/SIMULATOR.md
@@ -31,7 +31,7 @@ The simulator can be started with the command-line options listed in the table b
 | -i[[`<whitespace>`]`<integer>`] | Set the maximum time waiting for an image to match the expected image during testing. Default = 500 ms. |
 | -k[[`<whitespace>`]`<argument>`] | Load a saved keymap to change keyboard layout. |
 | -K | Simulate typing of individual keys during tests. |
-| -m[[`<whitespace>`]`<integer>`] | Set the memory size available to the calculator in megabytes. |
+| -m[[`<whitespace>`]`<integer>`] | Set the memory size available to the calculator in kilobytes. |
 | -n | Enable beeps while running the test suite (noisy testing). |
 | -r[[`<whitespace>`]`<integer>`] | Set the time to wait for a screen update in milliseconds. Default = 20 ms. |
 | -s[[`<whitespace>`]`<real>`] | Scale the application window by the given floating-point scaling factor. |
diff --git a/src/constants.cc b/src/constants.cc
index 590d4782..445956f5 100644
--- a/src/constants.cc
+++ b/src/constants.cc
@@ -644,7 +644,7 @@ static const cstring basic_constants[] =
     // *Tau mass - Measurement
     "mτ",       "[ 1.90754_u "
                 "  0.00013_u "
-                "  'ROUND(UBASE(Ⓢmμ/Ⓒmμ);-2)' ]",
+                "  'ROUND(UBASE(Ⓢmτ/Ⓒmτ);-2)' ]",
 
     // ------------------------------------------------------------------------
     // *mpme ratio - Measurement