diff --git a/compiler/desugared/from_surface.ml b/compiler/desugared/from_surface.ml
index fef2d146..d9af0fc5 100644
--- a/compiler/desugared/from_surface.ml
+++ b/compiler/desugared/from_surface.ml
@@ -375,7 +375,7 @@ let rec translate_expr
           (try
              Runtime.date_of_numbers date.literal_date_year
                date.literal_date_month date.literal_date_day
-           with Dates_calc.Dates.InvalidDate ->
+           with Failure _ ->
              Message.error ~pos
                "There is an error in this date, it does not correspond to a \
                 correct calendar day")
diff --git a/compiler/shared_ast/print.ml b/compiler/shared_ast/print.ml
index 513d4910..e391a22a 100644
--- a/compiler/shared_ast/print.ml
+++ b/compiler/shared_ast/print.ml
@@ -1051,13 +1051,13 @@ module UserFacing = struct
      and some others not, adding confusion. *)
 
   let date (lang : Global.backend_lang) ppf d =
-    let y, m, d = Dates_calc.Dates.date_to_ymd d in
+    let y, m, d = Runtime.date_to_years_months_days d in
     match lang with
     | En | Pl -> Format.fprintf ppf "%04d-%02d-%02d" y m d
     | Fr -> Format.fprintf ppf "%02d/%02d/%04d" d m y
 
   let duration (lang : Global.backend_lang) ppf dr =
-    let y, m, d = Dates_calc.Dates.period_to_ymds dr in
+    let y, m, d = Runtime.duration_to_years_months_days dr in
     let rec filter0 = function
       | (0, _) :: (_ :: _ as r) -> filter0 r
       | x :: r -> x :: List.filter (fun (n, _) -> n <> 0) r
diff --git a/compiler/surface/dune b/compiler/surface/dune
index ed6a89d9..67e1a3a5 100644
--- a/compiler/surface/dune
+++ b/compiler/surface/dune
@@ -8,7 +8,6 @@
   re
   zarith
   zarith_stubs_js
-  dates_calc
   shared_ast)
  (preprocess
   (pps sedlex.ppx visitors.ppx)))
diff --git a/runtimes/ocaml/runtime.ml b/runtimes/ocaml/runtime.ml
index d020b18d..e7e90b22 100644
--- a/runtimes/ocaml/runtime.ml
+++ b/runtimes/ocaml/runtime.ml
@@ -206,11 +206,16 @@ let day_of_month_of_date (d : date) : integer =
 (* This could fail, but is expected to only be called with known, already
    validated arguments by the generated code *)
 let date_of_numbers (year : int) (month : int) (day : int) : date =
-  Dates_calc.Dates.make_date ~year ~month ~day
+  try Dates_calc.Dates.make_date ~year ~month ~day
+  with Dates_calc.Dates.InvalidDate ->
+    failwith "date_of_numbers: invalid date"
 
 let date_to_string (d : date) : string =
   Format.asprintf "%a" Dates_calc.Dates.format_date d
 
+let date_to_years_months_days (d : date) : int * int * int =
+  Dates_calc.Dates.date_to_ymd d
+
 let first_day_of_month = Dates_calc.Dates.first_day_of_month
 let last_day_of_month = Dates_calc.Dates.last_day_of_month
 
@@ -219,19 +224,6 @@ let duration_of_numbers (year : int) (month : int) (day : int) : duration =
 
 let duration_to_string (d : duration) : string =
   Format.asprintf "%a" Dates_calc.Dates.format_period d
-(* breaks previous format *)
-(* let x, y, z = CalendarLib.Date.Period.ymd d in
- * let to_print =
- *   List.filter (fun (a, _) -> a <> 0) [x, "years"; y, "months"; z, "days"]
- * in
- * match to_print with
- * | [] -> "empty duration"
- * | _ ->
- *   Format.asprintf "%a"
- *     (Format.pp_print_list
- *        ~pp_sep:(fun fmt () -> Format.fprintf fmt ",@ ")
- *        (fun fmt (d, l) -> Format.fprintf fmt "%d %s" d l))
- *     to_print *)
 
 let duration_to_years_months_days (d : duration) : int * int * int =
   Dates_calc.Dates.period_to_ymds d
diff --git a/runtimes/ocaml/runtime.mli b/runtimes/ocaml/runtime.mli
index b17c8782..9b9124b5 100644
--- a/runtimes/ocaml/runtime.mli
+++ b/runtimes/ocaml/runtime.mli
@@ -315,10 +315,12 @@ val year_of_date : date -> integer
 val date_to_string : date -> string
 
 val date_of_numbers : int -> int -> int -> date
-(** Usage: [date_of_numbers year month day] *)
+(** Usage: [date_of_numbers year month day].
+    @raise Failure on invalid inputs *)
 
 val first_day_of_month : date -> date
 val last_day_of_month : date -> date
+val date_to_years_months_days : date -> int * int * int
 
 (**{2 Durations} *)
 
@@ -326,6 +328,7 @@ val duration_of_numbers : int -> int -> int -> duration
 (** Usage : [duration_of_numbers year mounth day]. *)
 
 val duration_to_years_months_days : duration -> int * int * int
+
 (**{2 Times} *)
 
 val duration_to_string : duration -> string