diff --git a/devtools/conda-build/meta.yaml b/devtools/conda-build/meta.yaml
index e4a8d95..c06f731 100644
--- a/devtools/conda-build/meta.yaml
+++ b/devtools/conda-build/meta.yaml
@@ -14,6 +14,7 @@ requirements:
   run:
   - python
   - pint
+  - numpy
 about:
   home: https://uibcdf.org
   license: MIT License
diff --git a/pyproject.toml b/pyproject.toml
index c29eb1b..a686864 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,6 +21,7 @@ classifiers = [
 requires-python = ">=3.9.0,<3.12.0"
 # Declare any run-time dependencies that should be installed with the package.
 dependencies = [
+    "numpy",
     "pint",
 ]