diff --git a/NEWS.md b/NEWS.md
index 0acb4ed63..9cfda4d46 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,6 +4,7 @@
 - `scoringutils` now depends on R 3.6. The change was made since packages `testthat` and `lifecycle`, which are used in `scoringutils` now require R 3.6. We also updated the Github action CI check to work with R 3.6 now. 
 
 ## Bug fixes
+- Fixes a bug with `set_forecast_unit()` where the function only workded with a data.table, but not a data.frame as an input. 
 - The metrics table in the vignette [Details on the metrics implemented in `scoringutils`](https://epiforecasts.io/scoringutils/articles/metric-details.html) had duplicated entries. This was fixed by removing the duplicated rows. 
 
 # scoringutils 1.2.1
@@ -11,9 +12,9 @@
 ## Package updates
 - This minor update fixes a few issues related to gh actions and the vignettes displayed at epiforecasts.io/scoringutils. It
   - Gets rid of the preferably package in _pkgdown.yml. The theme had a toggle between light and dark theme that didn't work properly
-  - updates the gh pages deploy action to v4 and also cleans up files when triggered
-  - introduces a gh action to automatically render the Readme from Readme.Rmd
-  - removes links to vignettes that have been renamed
+  - Updates the gh pages deploy action to v4 and also cleans up files when triggered
+  - Introduces a gh action to automatically render the Readme from Readme.Rmd
+  - Removes links to vignettes that have been renamed
 
 # scoringutils 1.2.0
 
diff --git a/R/convenience-functions.R b/R/convenience-functions.R
index f21aeefc8..41592d7d4 100644
--- a/R/convenience-functions.R
+++ b/R/convenience-functions.R
@@ -235,7 +235,7 @@ log_shift <- function(x, offset = 0, base = exp(1)) {
 #' )
 
 set_forecast_unit <- function(data, forecast_unit) {
-
+  data <- as.data.table(data)
   datacols <- colnames(data)
   missing <- forecast_unit[!(forecast_unit %in% datacols)]
 
diff --git a/tests/testthat/test-convenience-functions.R b/tests/testthat/test-convenience-functions.R
index ad7a40550..4fea72fa9 100644
--- a/tests/testthat/test-convenience-functions.R
+++ b/tests/testthat/test-convenience-functions.R
@@ -82,3 +82,20 @@ test_that("function get_forecast_unit() and set_forecast_unit() work together",
   expect_equal(fu_set, fu_get)
 })
 
+
+test_that("set_forecast_unit() works on input that's not a data.table", {
+  df <- data.frame(
+    a = 1:2,
+    b = 2:3,
+    c = 3:4
+  )
+  expect_equal(
+    colnames(set_forecast_unit(df, c("a", "b"))),
+    c("a", "b")
+  )
+  # apparently it also works on a matrix... good to know :)
+  expect_equal(
+    names(set_forecast_unit(as.matrix(df), "a")),
+    "a"
+  )
+})