How to Send Automated Email Reminders from Google Sheets

The DIY way

The DIY route is a time-based Apps Script trigger that scans your sheet each morning and emails anything due within a lead window.

function run() {
  var LEAD_DAYS = 7;
  var TO = 'you@example.com';
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('items');
  var rows = sheet.getDataRange().getValues();
  var now = new Date().getTime();
  var lead = LEAD_DAYS * 86400000;
  var due = [];
  for (var i = 1; i < rows.length; i++) {
    var name = rows[i][0], date = new Date(rows[i][1]);
    if (!name || isNaN(date.getTime())) continue;
    var diff = date.getTime() - now;
    if (diff >= -86400000 && diff <= lead) {
      due.push('• ' + name + ' — due ' +
        Utilities.formatDate(date, Session.getScriptTimeZone(), 'MMM d, yyyy'));
    }
  }
  if (due.length) {
    MailApp.sendEmail(TO, due.length + ' item(s) due soon', due.join('\n'));
  }
}

The DIY way, step by step

Put your data in a tab called "items" with three columns: name, due_date, notes. Then open Extensions → Apps Script and paste the function above.

It reads every row, parses the due date, and collects anything falling inside a seven-day lead window (plus a one-day grace for same-day items). If the list is non-empty, it sends you a single digest email. Nothing due means no email.

Run it every morning with a trigger

A function only helps if it runs on its own. In the Apps Script editor open Triggers (the clock icon), add a trigger for run(), choose "Time-driven" → "Day timer" → 8am–9am, and save. Google runs it on their servers — your computer can be off.

The first run prompts you to authorize the script. That is expected for any script you just wrote; approve it once and the daily schedule takes over.

Where the DIY path gets tedious

The script works, but every change means going back into the code or the raw Sheet: adding a reminder is a new row, changing the lead time is editing a constant, and there is no interface for anyone who is not comfortable in a spreadsheet.

That is the gap the one-click version closes.

The one-click alternative: Reminder Radar

Reminder Radar is this exact automation, provisioned into your own Google account: a daily cron plus a password-protected admin page. You add reminders and change the lead window from the admin page — never touching the Sheet — and the daily trigger reads your settings live.

It installs as a Drive folder, a Sheet, and an Apps Script web app that runs as you. No server, no subscription, and the data is yours. You can still open the Sheet and the code anytime; you just do not have to.