diff --git a/docs/sources/reference/singlestat.md b/docs/sources/reference/singlestat.md
index f22d496323a..9f2edb7df05 100644
--- a/docs/sources/reference/singlestat.md
+++ b/docs/sources/reference/singlestat.md
@@ -31,6 +31,7 @@ The singlestat panel has a normal query editor to allow you define your exact me
    * `total` - The sum of all the non-null values in the series
    * `first` - The first value in the series
    * `delta` - The total incremental increase (of a counter) in the series. An attempt is made to account for counter resets, but this will only be accurate for single instance metrics. Used to show total counter increase in time series.
+   * `diff` - The difference betwen 'current' (last value) and 'first'.
    * `range` - The difference between 'min' and 'max'. Useful the show the range of change for a gauge.
 4. `Postfixes`: The Postfix fields let you define a custom label and font-size (as a %) to appear *after* the value
 5. `Units`: Units are appended to the the Singlestat  within the panel, and will respect the color and threshold settings for the value.