diff --git a/rslib/src/backend/scheduler/mod.rs b/rslib/src/backend/scheduler/mod.rs
index b5366a2a0..3f612bc91 100644
--- a/rslib/src/backend/scheduler/mod.rs
+++ b/rslib/src/backend/scheduler/mod.rs
@@ -180,7 +180,7 @@ impl From<crate::scheduler::timing::SchedTimingToday> for pb::SchedTimingTodayOu
     fn from(t: crate::scheduler::timing::SchedTimingToday) -> pb::SchedTimingTodayOut {
         pb::SchedTimingTodayOut {
             days_elapsed: t.days_elapsed,
-            next_day_at: t.next_day_at,
+            next_day_at: t.next_day_at.0,
         }
     }
 }
diff --git a/rslib/src/scheduler/answering/mod.rs b/rslib/src/scheduler/answering/mod.rs
index fb5501291..c6ea0acd8 100644
--- a/rslib/src/scheduler/answering/mod.rs
+++ b/rslib/src/scheduler/answering/mod.rs
@@ -93,7 +93,7 @@ impl CardStateUpdater {
     }
 
     fn secs_until_rollover(&self) -> u32 {
-        (self.timing.next_day_at - self.now.0).max(0) as u32
+        self.timing.next_day_at.elapsed_secs_since(self.now) as u32
     }
 
     fn into_card(self) -> Card {
@@ -197,7 +197,7 @@ impl Collection {
         let collapse_time = self.learn_ahead_secs();
         let now = TimestampSecs::now();
         let timing = self.timing_for_timestamp(now)?;
-        let secs_until_rollover = (timing.next_day_at - now.0).max(0) as u32;
+        let secs_until_rollover = timing.next_day_at.elapsed_secs_since(now).max(0) as u32;
 
         Ok(vec![
             answer_button_time_collapsible(
diff --git a/rslib/src/scheduler/queue/learning.rs b/rslib/src/scheduler/queue/learning.rs
index 3d2cea37b..4ce4a713f 100644
--- a/rslib/src/scheduler/queue/learning.rs
+++ b/rslib/src/scheduler/queue/learning.rs
@@ -66,7 +66,7 @@ impl CardQueues {
         timing: SchedTimingToday,
     ) -> Option<LearningQueueEntry> {
         // not due today?
-        if !card.is_intraday_learning() || card.due >= timing.next_day_at as i32 {
+        if !card.is_intraday_learning() || card.due >= timing.next_day_at.0 as i32 {
             return None;
         }
 
diff --git a/rslib/src/scheduler/timing.rs b/rslib/src/scheduler/timing.rs
index e5de473c5..6e5c154ba 100644
--- a/rslib/src/scheduler/timing.rs
+++ b/rslib/src/scheduler/timing.rs
@@ -10,7 +10,7 @@ pub struct SchedTimingToday {
     /// The number of days that have passed since the collection was created.
     pub days_elapsed: u32,
     /// Timestamp of the next day rollover.
-    pub next_day_at: i64,
+    pub next_day_at: TimestampSecs,
 }
 
 /// Timing information for the current day.
@@ -34,11 +34,11 @@ pub fn sched_timing_today_v2_new(
     // rollover
     let rollover_today_datetime = today.and_hms(rollover_hour as u32, 0, 0);
     let rollover_passed = rollover_today_datetime <= now_datetime;
-    let next_day_at = if rollover_passed {
+    let next_day_at = TimestampSecs(if rollover_passed {
         (rollover_today_datetime + Duration::days(1)).timestamp()
     } else {
         rollover_today_datetime.timestamp()
-    };
+    });
 
     // day count
     let days_elapsed = days_elapsed(created_date, today, rollover_passed);
@@ -119,7 +119,7 @@ fn v1_creation_date_adjusted_to_hour_inner(crt: i64, hour: u8, offset: FixedOffs
 
 fn sched_timing_today_v1(crt: TimestampSecs, now: TimestampSecs) -> SchedTimingToday {
     let days_elapsed = (now.0 - crt.0) / 86_400;
-    let next_day_at = crt.0 + (days_elapsed + 1) * 86_400;
+    let next_day_at = TimestampSecs(crt.0 + (days_elapsed + 1) * 86_400);
     SchedTimingToday {
         now,
         days_elapsed: days_elapsed as u32,
@@ -140,13 +140,14 @@ fn sched_timing_today_v2_legacy(
         .timestamp();
     let days_elapsed = (now.0 - crt_at_rollover) / 86_400;
 
-    let mut next_day_at = now
-        .datetime(current_utc_offset)
-        .date()
-        .and_hms(rollover as u32, 0, 0)
-        .timestamp();
-    if next_day_at < now.0 {
-        next_day_at += 86_400;
+    let mut next_day_at = TimestampSecs(
+        now.datetime(current_utc_offset)
+            .date()
+            .and_hms(rollover as u32, 0, 0)
+            .timestamp(),
+    );
+    if next_day_at < now {
+        next_day_at = next_day_at.adding_secs(86_400);
     }
 
     SchedTimingToday {
@@ -321,7 +322,7 @@ mod test {
             *now.offset(),
             rollhour as u8,
         );
-        assert_eq!(today.next_day_at, next_day_at.timestamp());
+        assert_eq!(today.next_day_at.0, next_day_at.timestamp());
 
         // after the rollover, the next day should be the next day
         let now = Local.ymd(2019, 1, 3).and_hms(rollhour, 0, 0);
@@ -333,7 +334,7 @@ mod test {
             *now.offset(),
             rollhour as u8,
         );
-        assert_eq!(today.next_day_at, next_day_at.timestamp());
+        assert_eq!(today.next_day_at.0, next_day_at.timestamp());
 
         // after the rollover, the next day should be the next day
         let now = Local.ymd(2019, 1, 3).and_hms(rollhour + 3, 0, 0);
@@ -345,7 +346,7 @@ mod test {
             *now.offset(),
             rollhour as u8,
         );
-        assert_eq!(today.next_day_at, next_day_at.timestamp());
+        assert_eq!(today.next_day_at.0, next_day_at.timestamp());
     }
 
     #[test]
@@ -357,7 +358,7 @@ mod test {
             SchedTimingToday {
                 now,
                 days_elapsed: 107,
-                next_day_at: 1584558000
+                next_day_at: TimestampSecs(1584558000)
             }
         );
 
@@ -366,7 +367,7 @@ mod test {
             SchedTimingToday {
                 now,
                 days_elapsed: 589,
-                next_day_at: 1584540000
+                next_day_at: TimestampSecs(1584540000)
             }
         );
 
@@ -375,7 +376,7 @@ mod test {
             SchedTimingToday {
                 now,
                 days_elapsed: 700,
-                next_day_at: 1584554400
+                next_day_at: TimestampSecs(1584554400)
             }
         );
     }
diff --git a/rslib/src/search/sqlwriter.rs b/rslib/src/search/sqlwriter.rs
index 690343cec..3de6cbc41 100644
--- a/rslib/src/search/sqlwriter.rs
+++ b/rslib/src/search/sqlwriter.rs
@@ -210,8 +210,8 @@ impl SqlWriter<'_> {
 
     fn write_rated(&mut self, op: &str, days: i64, ease: &RatingKind) -> Result<()> {
         let today_cutoff = self.col.timing_today()?.next_day_at;
-        let target_cutoff_ms = (today_cutoff + 86_400 * days) * 1_000;
-        let day_before_cutoff_ms = (today_cutoff + 86_400 * (days - 1)) * 1_000;
+        let target_cutoff_ms = today_cutoff.adding_secs(86_400 * days).as_millis();
+        let day_before_cutoff_ms = today_cutoff.adding_secs(86_400 * (days - 1)).as_millis();
 
         write!(self.sql, "c.id in (select cid from revlog where id").unwrap();
 
@@ -224,13 +224,13 @@ impl SqlWriter<'_> {
                 self.sql,
                 " between {} and {}",
                 day_before_cutoff_ms,
-                target_cutoff_ms - 1
+                target_cutoff_ms.0 - 1
             ),
             "!=" => write!(
                 self.sql,
                 " not between {} and {}",
                 day_before_cutoff_ms,
-                target_cutoff_ms - 1
+                target_cutoff_ms.0 - 1
             ),
             _ => unreachable!("unexpected op"),
         }
@@ -479,14 +479,14 @@ impl SqlWriter<'_> {
 
     fn write_added(&mut self, days: u32) -> Result<()> {
         let timing = self.col.timing_today()?;
-        let cutoff = (timing.next_day_at - (86_400 * (days as i64))) * 1_000;
+        let cutoff = (timing.next_day_at.0 - (86_400 * (days as i64))) * 1_000;
         write!(self.sql, "c.id > {}", cutoff).unwrap();
         Ok(())
     }
 
     fn write_edited(&mut self, days: u32) -> Result<()> {
         let timing = self.col.timing_today()?;
-        let cutoff = timing.next_day_at - (86_400 * (days as i64));
+        let cutoff = timing.next_day_at.0 - (86_400 * (days as i64));
         write!(self.sql, "n.mod > {}", cutoff).unwrap();
         Ok(())
     }
@@ -646,7 +646,7 @@ mod test {
         let timing = ctx.timing_today().unwrap();
         assert_eq!(
             s(ctx, "added:3").0,
-            format!("(c.id > {})", (timing.next_day_at - (86_400 * 3)) * 1_000)
+            format!("(c.id > {})", (timing.next_day_at.0 - (86_400 * 3)) * 1_000)
         );
         assert_eq!(s(ctx, "added:0").0, s(ctx, "added:1").0,);
 
@@ -730,14 +730,14 @@ mod test {
             s(ctx, "rated:2").0,
             format!(
                 "(c.id in (select cid from revlog where id >= {} and ease > 0))",
-                (timing.next_day_at - (86_400 * 2)) * 1_000
+                (timing.next_day_at.0 - (86_400 * 2)) * 1_000
             )
         );
         assert_eq!(
             s(ctx, "rated:400:1").0,
             format!(
                 "(c.id in (select cid from revlog where id >= {} and ease = 1))",
-                (timing.next_day_at - (86_400 * 400)) * 1_000
+                (timing.next_day_at.0 - (86_400 * 400)) * 1_000
             )
         );
         assert_eq!(s(ctx, "rated:0").0, s(ctx, "rated:1").0);
@@ -747,7 +747,7 @@ mod test {
             s(ctx, "resched:400").0,
             format!(
                 "(c.id in (select cid from revlog where id >= {} and ease = 0))",
-                (timing.next_day_at - (86_400 * 400)) * 1_000
+                (timing.next_day_at.0 - (86_400 * 400)) * 1_000
             )
         );
 
diff --git a/rslib/src/stats/graphs.rs b/rslib/src/stats/graphs.rs
index 3746a36a3..c425850dd 100644
--- a/rslib/src/stats/graphs.rs
+++ b/rslib/src/stats/graphs.rs
@@ -22,11 +22,13 @@ impl Collection {
 
     fn graph_data(&mut self, all: bool, days: u32) -> Result<pb::GraphsOut> {
         let timing = self.timing_today()?;
-        let revlog_start = TimestampSecs(if days > 0 {
-            timing.next_day_at - (((days as i64) + 1) * 86_400)
+        let revlog_start = if days > 0 {
+            timing
+                .next_day_at
+                .adding_secs(-(((days as i64) + 1) * 86_400))
         } else {
-            0
-        });
+            TimestampSecs(0)
+        };
 
         let offset = self.local_utc_offset_for_user()?;
         let local_offset_secs = offset.local_minus_utc() as i64;
@@ -45,7 +47,7 @@ impl Collection {
             cards: cards.into_iter().map(Into::into).collect(),
             revlog,
             days_elapsed: timing.days_elapsed,
-            next_day_at_secs: timing.next_day_at as u32,
+            next_day_at_secs: timing.next_day_at.0 as u32,
             scheduler_version: self.scheduler_version() as u32,
             local_offset_secs: local_offset_secs as i32,
         })
diff --git a/rslib/src/storage/card/mod.rs b/rslib/src/storage/card/mod.rs
index 7aad29c36..7bd54221f 100644
--- a/rslib/src/storage/card/mod.rs
+++ b/rslib/src/storage/card/mod.rs
@@ -169,7 +169,7 @@ impl super::SqliteStorage {
     pub(crate) fn for_each_due_card_in_deck<F>(
         &self,
         day_cutoff: u32,
-        learn_cutoff: i64,
+        learn_cutoff: TimestampSecs,
         deck: DeckId,
         mut func: F,
     ) -> Result<()>
diff --git a/rslib/src/storage/revlog/mod.rs b/rslib/src/storage/revlog/mod.rs
index 67cf1861c..69495c032 100644
--- a/rslib/src/storage/revlog/mod.rs
+++ b/rslib/src/storage/revlog/mod.rs
@@ -133,11 +133,11 @@ impl SqliteStorage {
             .collect()
     }
 
-    pub(crate) fn studied_today(&self, day_cutoff: i64) -> Result<StudiedToday> {
-        let start = (day_cutoff - 86_400) * 1_000;
+    pub(crate) fn studied_today(&self, day_cutoff: TimestampSecs) -> Result<StudiedToday> {
+        let start = day_cutoff.adding_secs(-86_400).as_millis();
         self.db
             .prepare_cached(include_str!("studied_today.sql"))?
-            .query_map(&[start, RevlogReviewKind::Manual as i64], |row| {
+            .query_map(&[start.0, RevlogReviewKind::Manual as i64], |row| {
                 Ok(StudiedToday {
                     cards: row.get(0)?,
                     seconds: row.get(1)?,
diff --git a/rslib/src/timestamp.rs b/rslib/src/timestamp.rs
index d4fae5b4f..03330e6a9 100644
--- a/rslib/src/timestamp.rs
+++ b/rslib/src/timestamp.rs
@@ -19,10 +19,18 @@ impl TimestampSecs {
         Self(0)
     }
 
+    pub fn elapsed_secs_since(self, other: TimestampSecs) -> i64 {
+        self.0 - other.0
+    }
+
     pub fn elapsed_secs(self) -> u64 {
         (Self::now().0 - self.0).max(0) as u64
     }
 
+    pub fn as_millis(self) -> TimestampMillis {
+        TimestampMillis(self.0 * 1000)
+    }
+
     /// YYYY-mm-dd
     pub(crate) fn date_string(self) -> String {
         Local.timestamp(self.0, 0).format("%Y-%m-%d").to_string()