diff --git a/stew/results.nim b/stew/results.nim
index 5c29a99..cd24d2d 100644
--- a/stew/results.nim
+++ b/stew/results.nim
@@ -628,6 +628,36 @@ func mapCast*[T0: not void, E](
     else:
       result.err(self.eResultPrivate)
 
+func mapConvertErr*[T, E0](
+    self: Result[T, E0], E1: type): Result[T, E1] {.inline.} =
+  ## Convert result error to E1 using an conversion
+  # Would be nice if it was automatic...
+  when E0 is E1:
+    result = self
+  else:
+    if self.oResultPrivate:
+      when T is void:
+        result.ok()
+      else:
+        result.ok(self.vResultPrivate)
+    else:
+      when E1 is void:
+        result.err()
+      else:
+        result.err(E1(self.eResultPrivate))
+
+func mapCastErr*[T, E0](
+    self: Result[T, E0], E1: type): Result[T, E1] {.inline.} =
+  ## Convert result value to A using a cast
+  ## Would be nice with nicer syntax...
+  if self.oResultPrivate:
+    when T is void:
+      result.ok()
+    else:
+      result.ok(self.vResultPrivate)
+  else:
+    result.err(cast[E1](self.eResultPrivate))
+
 template `and`*[T0, E, T1](self: Result[T0, E], other: Result[T1, E]): Result[T1, E] =
   ## Evaluate `other` iff self.isOk, else return error
   ## fail-fast - will not evaluate other if a is an error
diff --git a/tests/test_results.nim b/tests/test_results.nim
index 3ce5fb7..3e894c2 100644
--- a/tests/test_results.nim
+++ b/tests/test_results.nim
@@ -131,6 +131,9 @@ block:
   doAssert (rErr.orErr(32)).error == 32
   doAssert (rOk.orErr(failFast())).get() == rOk.get()
 
+  doAssert rErr.mapConvertErr(cstring).error() == cstring(rErr.error())
+  doAssert rErr.mapCastErr(seq[byte]).error() == cast[seq[byte]](rErr.error())
+
   # string conversion
   doAssert $rOk == "ok(42)"
   doAssert $rErr == "err(dummy)"