diff --git a/package.json b/package.json
index 3d3e58e32..92c08c118 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,6 @@
     "d3-scale": "^1.0.5",
     "d3-selection": "^1.1.0",
     "d3-shape": "^1.2.0",
-    "d3-time-format": "^2.0.5",
     "d3-timer": "^1.0.7",
     "d3-transition": "^1.2.0",
     "d3-zoom": "^1.1.3",
diff --git a/src/util/dateHelpers.js b/src/util/dateHelpers.js
index 0972b9ea3..df77abd8a 100644
--- a/src/util/dateHelpers.js
+++ b/src/util/dateHelpers.js
@@ -1,38 +1,103 @@
-import { scaleTime } from "d3-scale";
-import { timeFormat, timeParse } from "d3-time-format";
-
-const dateFormatter = timeFormat("%Y-%m-%d");
-const dateParser = timeParse("%Y-%m-%d");
-const dateScale = scaleTime()
-  .domain([new Date(2000, 0, 0), new Date(2100, 0, 0)])
-  .range([2000, 2100]);
-
+/**
+ * Convert a numeric date to a calendar date (which is nicer to display)
+ * This is (for CE dates) meant to be used as the inverse ofthe TreeTime
+ * function `numeric_date` which places the numeric date at noon (12h00),
+ * i.e. Jan 1 is 0.5/365 of a year (if the year is not a leap year).
+ * @param {numeric} numDate Numeric date
+ * @returns {string} date in YYYY-MM-DD format for CE dates, YYYY for BCE dates
+ */
 export const numericToCalendar = (numDate) => {
-  if (numDate<0){
+  /* for BCE dates, return the (rounded) year */
+  if (numDate<0) {
     return Math.round(numDate).toString();
   }
-  const d3Date = dateScale.invert(numDate);
-  const calDate = dateFormatter(d3Date);
-  return calDate;
+  /* for CE dates, return string in YYYY-MM-DD format */
+  /* Beware: for `Date`, months are 0-indexed, days are 1-indexed */
+  const fracPart = numDate%1;
+  const year = parseInt(numDate, 10);
+  const nDaysInYear = isLeapYear(year) ? 366 : 365;
+  const nDays = fracPart * nDaysInYear;
+  const date = new Date((new Date(year, 0, 1)).getTime() + nDays*24*60*60*1000);
+  return dateToString(date);
 };
 
+/**
+ * Convert a calendar date to a numeric one.
+ * This function is meant to behave similarly to TreeTime's `numeric_date`
+ * as found in v0.7*. Note that for negative dates, i.e. BCE, no fraction
+ * in the year will be returned.
+ * @param {string} calDate in format YYYY-MM-DD
+ * @returns {float} YYYY.F, where F is the fraction of the year passed
+ */
 export const calendarToNumeric = (calDate) => {
-  if (calDate[0]==='-'){
+  if (calDate[0]==='-') {
     const pieces = calDate.substring(1).split('-');
     return -parseFloat(pieces[0]);
-  }else{
-    const d3Date = dateParser(calDate);
-    const numDate = dateScale(d3Date);
-    return numDate;
   }
+  /* Beware: for `Date`, months are 0-indexed, days are 1-indexed */
+  const [year, month, day] = calDate.split("-").map((n) => parseInt(n, 10));
+  const oneDayInMs = 86400000; // 1000 * 60 * 60 * 24
+  /* add on 1/2 day to let time represent noon (12h00) */
+  const elapsedDaysInYear = (Date.UTC(year, month-1, day) - Date.UTC(year, 0, 1)) / oneDayInMs + 0.5;
+  const fracPart = elapsedDaysInYear / (isLeapYear(year) ? 366 : 365);
+  return year + fracPart;
 };
 
-export const currentNumDate = () => {
-  const now = new Date();
-  return dateScale(now);
-};
+export const currentCalDate = () => dateToString(new Date());
 
-export const currentCalDate = () => {
-  const now = new Date();
-  return dateFormatter(now);
-};
+export const currentNumDate = () => calendarToNumeric(currentCalDate());
+
+function dateToString(date) {
+  return `${date.getFullYear()}-${String(date.getMonth()+1).padStart(2, '0')}-${String(date.getDate()).padStart(2, '0')}`;
+}
+
+function isLeapYear(year) {
+  return ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
+}
+
+/* ------------------------------------------------ TMP ---------------------------------------------- */
+/* Augur data taken using TreeTime v0.7 at d4450aac32cfafbb62492554d87e23ee4efa168f */
+const augurv7Data = [
+  ["1899-07-01", 1899.4972602739726],
+  ["2000-01-01", 2000.0013661202186],
+  ["2016-03-01", 2016.1653005464482],
+  ["2019-01-01", 2019.0013698630137],
+  ["2019-03-01", 2019.16301369863],
+  ["2019-12-01", 2019.9164383561645],
+  ["2100-01-01", 2100.0013698630137]
+];
+console.log("-------------------");
+console.log("Augur -> Treetime v0.7 -> Auspice (match?)");
+console.log("-------------------");
+augurv7Data.forEach((d) => {
+  console.log(`${d[0]} -> ${d[1]} -> ${numericToCalendar(d[1])} (${numericToCalendar(d[1]) === d[0]})`);
+});
+
+/* Augur data taken using TreeTime v0.6.4.1 */
+const augurv641Data = [
+  ["1899-07-01", 1899.498288843258],
+  ["2000-01-01", 2000.002737850787],
+  ["2016-03-01", 2016.167008898015],
+  ["2019-01-01", 2019.002737850787],
+  ["2019-03-01", 2019.1642710472279],
+  ["2019-12-01", 2019.9171800136892],
+  ["2100-01-01", 2100.002737850787]
+];
+console.log("-------------------");
+console.log("Augur -> Treetime v0.6.4.1 -> Auspice (match?)");
+console.log("-------------------");
+augurv641Data.forEach((d) => {
+  console.log(`${d[0]} -> ${d[1]} -> ${numericToCalendar(d[1])} (${numericToCalendar(d[1]) === d[0]})`);
+});
+
+console.log("")
+console.log("-------------------");
+console.log("Calendar dates -> numeric (matches Treetime v0.6.4.1 // 0.7*)");
+console.log("-------------------");
+augurv7Data.forEach((d, i) => {
+  const n = calendarToNumeric(d[0]);
+  const isClose = (a, b) => Math.abs(a-b) < 0.000001;
+  console.log(`${d[0]} -> ${n} (${isClose(n, augurv641Data[i][1])} // ${isClose(n, d[1])})`);
+});
+
+/* -------------------------------------------- END  TMP ---------------------------------------------- */