diff --git a/R/progress.R b/R/progress.R
index d72da62..84d54dd 100644
--- a/R/progress.R
+++ b/R/progress.R
@@ -246,9 +246,9 @@ pb_init <- function(self, private, format, total, width, stream,
   assert_character_scalar(format)
   assert_nonnegative_scalar(total <- as.numeric(total), na = TRUE)
   assert_nonzero_count(width)
-  assert_single_char(complete)
-  assert_single_char(incomplete)
-  assert_single_char(current)
+  assert_single_char(complete, strip_color = TRUE)
+  assert_single_char(incomplete, strip_color = TRUE)
+  assert_single_char(current, strip_color = TRUE)
   assert_function(callback)
   assert_flag(clear)
   assert_nonnegative_scalar(show_after)
diff --git a/R/utils.R b/R/utils.R
index ec41151..4ddc545 100644
--- a/R/utils.R
+++ b/R/utils.R
@@ -108,9 +108,14 @@ assert_connection <- function(x) {
   stopifnot(inherits(x, "connection"))
 }
 
-assert_single_char <- function(x) {
+#' @importFrom crayon col_nchar
+assert_single_char <- function(x, strip_color = FALSE) {
   assert_character_scalar(x)
-  stopifnot(nchar(x) == 1)
+  if (strip_color) {
+    stopifnot(col_nchar(x) == 1)
+  } else {
+    stopifnot(nchar(x) == 1)
+  }
 }
 
 assert_function <- function(x) {