diff --git a/yotta/data/example-benchmark/README.md b/yotta/data/example-benchmark/README.md
index 1a534a2f3..8589e7bd6 100644
--- a/yotta/data/example-benchmark/README.md
+++ b/yotta/data/example-benchmark/README.md
@@ -92,3 +92,9 @@ To build and run this example you must have:
     {{success}}
     {{end}}
     ```
+
+Any performance data generated by this example application are indicative only of the performance of the mbed TLS module on the platform it's executed on.
+
+Differences in the integration of mbed TLS into the platform, such as whether all available hardware accelerators have been used or not, can lead to significant differences in performance, and so results from the program are not intended to be used to meaningfully compare platforms.
+
+The figures may also slightly change from execution to execution due to variations in the timing functions.