Free online calendar: how to pick one that sends invites and syncs with your phone

A coach runs her week from three places: a paper planner on the desk, the calendar app on her phone and a column of dates in a spreadsheet for client sessions. On Monday a client books a Thursday call by email, she writes it in the planner, forgets to copy it to the phone and spends Thursday afternoon at the gym while the client waits on a link.

Most double bookings aren't about discipline. They happen because the calendar lives in more than one place. This guide explains what a free online calendar is, what to compare before you pick one, how email invites and phone sync work, and how to set up a free calendar in a few minutes.

What is a free online calendar?

A free online calendar is a calendar stored on a server and opened in a browser, at no cost, so the same events appear on every device you sign in to. Change an event on the laptop and the phone shows the change too.

That's the difference from a calendar that lives only on one device or on paper. The server is the single source of truth, and every screen is just a window into it. For anyone who books calls with clients, that's what ends the "I wrote it somewhere" problem.

What should you look for in a free calendar app?

Look for email invites guests can accept without an account, sync with your phone's calendar app, correct time zones, the views you actually use and a way to get your events out later. Price doesn't separate free options, so these features do.

If a must-have for you isn't in that list, such as shared family calendars or reminder settings, check before you switch. The LAWD Agenda page lists month and week views, all-day events, email invites and phone sync, and doesn't list calendar sharing or reminders.

How do calendar invites by email work?

A calendar invite by email is a message that carries the event in a standard calendar format, so the guest's email or calendar app can show it and record their reply. The standard for this is iMIP, described in RFC 6047, which defines how calendar scheduling messages travel over email.

In practice:

1. You create the event and add the guest's email address.
2. The calendar server sends the invite to that address.
3. The guest's own calendar recognizes it, whether they use Gmail, Outlook or Apple Calendar, and they can add the event without creating an account anywhere.

Because the format is a shared standard, you don't need to know which app each client uses. That matters for service businesses: your clients shouldn't have to install anything to book a call with you.

How do you sync an online calendar with your iPhone or Android?

You add the calendar to your phone as a CalDAV account, using the server address and a password from your calendar provider. CalDAV, defined in RFC 4791, is a standard way for apps to read, create and change calendar events stored on a server.

On iPhone, Apple's guide to the Calendar settings describes the path: in Settings, open the Calendar app's settings, go to the calendar accounts, choose Add Account, then Other, then Add CalDAV Account, and enter the server and your account details. The exact menu names can shift a little between iOS versions.

On Android, the usual route is a sync app. DAVx5 is an open-source app that syncs CalDAV calendars, CardDAV address books and task lists with the phone, so the events show up in the calendar app you already use. It's sold in app stores for a modest charge, and you can compile it yourself for free.

For LAWD Agenda, the details come from LAWD Mail's "use on your phone" screen:

The same app password works for email (IMAP and SMTP), calendar and contacts, so one setup on the phone brings all three.

How do you set up a free online calendar for client calls?

Create the account, connect your phone, then build one routine: every call gets an event with the client as a guest, the meeting link in the location field and the agenda in the description. That routine is what keeps the calendar trustworthy.

With LAWD Agenda:

1. Create a free LAWD account at mail.lawd.me/criar. The same account opens LAWD Mail, LAWD Agenda and LAWD Box.
2. Open agenda.lawd.me and pick the month or week view.
3. Create the event with date, time and time zone. Use all-day events for deadlines and days off.
4. Invite the client by email. The invite reaches their inbox and works with their own calendar.
5. Connect your phone over CalDAV with an app password, so the event follows you.

One honest note: the LAWD app screens are in Portuguese for now, while the public pages are in English.

When a call comes from a lead, record it in your pipeline too, so the next step has a date, as described in this guide to a simple CRM for service businesses. If most of your calls start as Instagram conversations, see how to get clients from Instagram.

How to do it in LUME Hub

LUME Hub is an all-in-one platform for small businesses, consultants and agencies that brings content, sales, clients, finance and AI together in the browser. LAWD Agenda is the free calendar of the same ecosystem: it runs on its own at agenda.lawd.me and opens from the Hub's app launcher with the same account.

LAWD Agenda is free. Meetings is included in LUME Hub plans from Essential up: start your 7-day free trial with no credit card, or see the plans.

Summary

A free online calendar keeps your events on a server, so every device shows the same day. Pick one that sends standard email invites guests can accept without an account, syncs with your phone over CalDAV, stores time zones per event and has the views you use. On iPhone, add a CalDAV account in the Calendar settings; on Android, use a sync app such as DAVx5. LAWD Agenda does this for free, with month and week views and the same account as LAWD Mail and LAWD Box. Your next step: move next week's calls into one calendar, invite each client to their event and connect your phone before Monday.