diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4fbf3079a..a480e9f58 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Attempting to differentiate server-side field projections now raises a clear error instead of silently failing.
 - Improved error message and handling when attempting to load a non-existent task ID.
 - `ClipOperation` now fails validation if traced fields are detected.
+- Warn if more than 20 frequencies are used in EME, as this may lead to slower or more expensive simulations.
 
 ## [2.8.3] - 2025-04-24
 
@@ -36,6 +37,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 - Performance enhancement for adjoint gradient calculations by optimizing field interpolation.
 - Auto grid in EME simulations with multiple `freqs` provided uses the largest instead of raising an error.
+- Increased maximum number of frequencies in an EME simulation from 20 to 500
 - Named mediums now display by name for brevity; materials/variants print concise summaries including references.
 
 ### Fixed
diff --git a/tidy3d/components/eme/simulation.py b/tidy3d/components/eme/simulation.py
index 36868f005..c4a844e3d 100644
--- a/tidy3d/components/eme/simulation.py
+++ b/tidy3d/components/eme/simulation.py
@@ -45,7 +45,7 @@
 
 
 # eme specific simulation parameters
-WARN_NUM_FREQS = 100
+WARN_NUM_FREQS = 20
 MAX_NUM_FREQS = 500
 MAX_NUM_SWEEP = 100