diff --git a/R/00utils.R b/R/00utils.R
index a59c136..02cb193 100644
--- a/R/00utils.R
+++ b/R/00utils.R
@@ -1,13 +1,13 @@
 # parses from/to params for get_measurements_ and get_boxes_
 parse_dateparams = function (from, to) {
-  from = utc_date(from)
-  to = utc_date(to)
+  from = date_as_utc(from)
+  to = date_as_utc(to)
   if (from - to > 0) stop('"from" must be earlier than "to"')
   c(date_as_isostring(from), date_as_isostring(to))
 }
 
 # NOTE: cannot handle mixed vectors of POSIXlt and POSIXct
-utc_date = function (date) {
+date_as_utc = function (date) {
   time = as.POSIXct(date)
   attr(time, 'tzone') = 'UTC'
   time
@@ -16,6 +16,8 @@ utc_date = function (date) {
 # NOTE: cannot handle mixed vectors of POSIXlt and POSIXct
 date_as_isostring = function (date) format.Date(date, format = '%FT%TZ')
 
+isostring_as_date = function (x) as.POSIXct(strptime(x, format = '%FT%T', tz = 'GMT'))
+
 #' Checks for an interactive session using interactive() and a knitr process in
 #' the callstack. See https://stackoverflow.com/a/33108841
 #'
diff --git a/R/box.R b/R/box.R
index 0004b3c..d3186fb 100644
--- a/R/box.R
+++ b/R/box.R
@@ -97,7 +97,7 @@ osem_boxes = function (exposure = NA, model = NA, grouptag = NA,
   if (!is.na(to) && !is.na(from))
     query$date = parse_dateparams(from, to) %>% paste(collapse = ',')
   else if (!is.na(date))
-    query$date = utc_date(date) %>% date_as_isostring()
+    query$date = date_as_utc(date) %>% date_as_isostring()
 
   do.call(get_boxes_, query)
 }
@@ -152,11 +152,11 @@ parse_senseboxdata = function (boxdata) {
   thebox = as.data.frame(boxdata, stringsAsFactors = F)
 
   # parse timestamps (updatedAt might be not defined)
-  thebox$createdAt = as.POSIXct(strptime(thebox$createdAt, format = '%FT%T', tz = 'GMT'))
+  thebox$createdAt = isostring_as_date(thebox$createdAt)
   if (!is.null(thebox$updatedAt))
-    thebox$updatedAt = as.POSIXct(strptime(thebox$updatedAt, format = '%FT%T', tz = 'GMT'))
+    thebox$updatedAt = isostring_as_date(thebox$updatedAt)
   if (!is.null(lastMeasurement))
-    thebox$lastMeasurement = as.POSIXct(strptime(lastMeasurement, format = '%FT%T', tz = 'GMT'))
+    thebox$lastMeasurement = isostring_as_date(lastMeasurement)
 
   # create a dataframe of sensors
   thebox$sensors = sensors %>%
diff --git a/R/box_utils.R b/R/box_utils.R
index 5775e11..a21ef2d 100644
--- a/R/box_utils.R
+++ b/R/box_utils.R
@@ -46,7 +46,7 @@ summary.sensebox = function(object, ...) {
   table(object$model) %>% print()
   cat('\n')
 
-  diffNow = (utc_date(Sys.time()) - object$lastMeasurement) %>% as.numeric(unit = 'hours')
+  diffNow = (date_as_utc(Sys.time()) - object$lastMeasurement) %>% as.numeric(unit = 'hours')
   list(
     'last_measurement_within' = c(
       '1h'    = nrow(dplyr::filter(object, diffNow <= 1)),
diff --git a/R/measurement.R b/R/measurement.R
index 591c4cb..4653a5f 100644
--- a/R/measurement.R
+++ b/R/measurement.R
@@ -180,8 +180,8 @@ parse_get_measurements_params = function (params) {
 
   if (!is.na(params$from) && !is.na(params$to)) {
     parse_dateparams(params$from, params$to) # only for validation sideeffect
-    query$`from-date` = utc_date(params$from)
-    query$`to-date` = utc_date(params$to)
+    query$`from-date` = date_as_utc(params$from)
+    query$`to-date` = date_as_utc(params$to)
   }
 
   if (!is.na(params$exposure)) query$exposure = params$exposure