diff --git a/ifc/src/lib.rs b/ifc/src/lib.rs
index 30db983..d3b1417 100644
--- a/ifc/src/lib.rs
+++ b/ifc/src/lib.rs
@@ -12,6 +12,7 @@ You should have received a copy of the GNU General Public License along with Lum
 
 use chrono::{Datelike, NaiveDate};
 use serde::{Deserialize, Serialize};
+use std::convert::TryInto;
 use thiserror::Error;
 
 #[derive(Clone, Debug, Error, PartialEq)]
@@ -206,9 +207,27 @@ pub struct Day {
     day: u8,
 }
 
-impl From<chrono::NaiveDate> for Day {
+impl From<chrono::NaiveDate> for IFC {
     fn from(date: chrono::NaiveDate) -> Self {
-        unimplemented!();
+        if date.month() == 12 && date.day() == 31 {
+            Self::YearDay(date.year())
+        } else if is_leap_year(date.year()) && date.month() == 6 && date.day() == 17 {
+            Self::LeapDay(date.year())
+        } else {
+            let mut days = date.ordinal();
+            if is_leap_year(date.year())
+                && date > NaiveDate::from_ymd_opt(date.year(), 6, 17).unwrap()
+            {
+                days = days - 1;
+            }
+            let month: u8 = (days / 28).try_into().unwrap();
+            let day: u8 = (days % 28).try_into().unwrap();
+            Self::Day(Day {
+                year: date.year(),
+                month: month + 1,
+                day,
+            })
+        }
     }
 }
 
@@ -586,6 +605,141 @@ mod tests {
         assert_eq!(IFC::ymd(12022, 13, 28).unwrap().week_ordinal0(), 51);
     }
 
+    #[test]
+    fn it_converts_from_gregorian() {
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 1, 1).unwrap()),
+            IFC::ymd(12022, 1, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 1, 29).unwrap()),
+            IFC::ymd(12022, 2, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 2, 26).unwrap()),
+            IFC::ymd(12022, 3, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 3, 26).unwrap()),
+            IFC::ymd(12022, 4, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 4, 23).unwrap()),
+            IFC::ymd(12022, 5, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 5, 21).unwrap()),
+            IFC::ymd(12022, 6, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 6, 18).unwrap()),
+            IFC::ymd(12022, 7, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 7, 16).unwrap()),
+            IFC::ymd(12022, 8, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 8, 13).unwrap()),
+            IFC::ymd(12022, 9, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 9, 10).unwrap()),
+            IFC::ymd(12022, 10, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 10, 8).unwrap()),
+            IFC::ymd(12022, 11, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 11, 5).unwrap()),
+            IFC::ymd(12022, 12, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 12, 3).unwrap()),
+            IFC::ymd(12022, 13, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12022, 12, 31).unwrap()),
+            IFC::YearDay(12022)
+        );
+    }
+
+    #[test]
+    fn it_converts_from_gregorian_on_leap_year() {
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 1, 1).unwrap()),
+            IFC::ymd(12020, 1, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 1, 29).unwrap()),
+            IFC::ymd(12020, 2, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 2, 26).unwrap()),
+            IFC::ymd(12020, 3, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 2, 28).unwrap()),
+            IFC::ymd(12020, 3, 3).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 2, 29).unwrap()),
+            IFC::ymd(12020, 3, 4).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 3, 1).unwrap()),
+            IFC::ymd(12020, 3, 5).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 3, 25).unwrap()),
+            IFC::ymd(12020, 4, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 4, 22).unwrap()),
+            IFC::ymd(12020, 5, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 5, 20).unwrap()),
+            IFC::ymd(12020, 6, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 6, 17).unwrap()),
+            IFC::LeapDay(12020)
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 6, 18).unwrap()),
+            IFC::ymd(12020, 7, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 7, 16).unwrap()),
+            IFC::ymd(12020, 8, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 8, 13).unwrap()),
+            IFC::ymd(12020, 9, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 9, 10).unwrap()),
+            IFC::ymd(12020, 10, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 10, 8).unwrap()),
+            IFC::ymd(12020, 11, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 11, 5).unwrap()),
+            IFC::ymd(12020, 12, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 12, 3).unwrap()),
+            IFC::ymd(12020, 13, 1).unwrap()
+        );
+        assert_eq!(
+            IFC::from(NaiveDate::from_ymd_opt(12020, 12, 31).unwrap()),
+            IFC::YearDay(12020)
+        );
+    }
     /*
     #[test]
     fn check_start_of_month() {