A Fractional Executive Calendar That Spans Every Company You Serve

Three companies. Three locked tenants. One of you.

If you are a fractional CFO, CTO, or CMO, your calendar is not one calendar. The fractional executive calendar problem is simple to state and miserable to live with: every client gave you an account in their Microsoft 365 or Google Workspace tenant, every tenant is locked down, and none of them know the others exist. Board prep for one client, month-end close for another, a pipeline review for the third, all scheduled by people who have no idea the other companies are on your plate.

You are on an engagement letter, not an org chart. There is no IT relationship to lean on. Nobody at any client is going to file a change request so their part-time executive can merge calendars, and asking makes you look like overhead, which is the one thing a fractional executive can never afford to look like.

Why the standard fixes fail at exactly three tenants

Cross-tenant calendar sharing needs admins on both sides to configure it. With three clients that means three IT departments coordinating around a person who is not their employee. It does not happen.

Cloud sync tools have a harder wall to climb. Since November 2025, Microsoft Entra default settings block users from consenting to third-party apps that request calendar permissions (Calendars.Read or Calendars.ReadWrite). An admin has to approve each app, in each tenant. Existing grants were grandfathered in, but every new connection needs a ticket. CalendarBridge, OneCal, Reclaim.ai, and Morgen all publish help articles walking users through requesting that admin approval, because their model connects to each account on the server side.

To be fair to them: if every one of your clients' admins will say yes, CalendarBridge is a genuinely good cloud option, with patented server-mediated two-way sync, booking pages, a HIPAA BAA, and plans from 4 to 32 dollars per user per month. The tool is not the problem. The problem is that you need three separate IT departments to approve it, and you have leverage with none of them. One yes out of three still leaves your calendar broken.

The tab you already have open is the integration

manyCalendars takes the other path. It is a desktop browser extension. You open each client's calendar in a browser tab, the way you already do every morning, and Tab Sync reads what is visible in that tab. The calendar follows its tab. Nothing gets installed in the client tenant, no OAuth grant is issued, no data leaves your machine, and it is read-only on the source, so it cannot create, move, or delete anything inside a client's environment.

It is, as far as we know, the only calendar tool that works when IT says no. Not by going around anyone: you are reading a calendar you are already signed into, with the access your client already gave you.

The Free tier does not even need Tab Sync. Unlimited manual calendars from .ics files and feed URLs, month, week, and day views, color coding per company, 100 percent local, no account needed. If one of your clients still allows feed URLs, start there.

Built for board weeks

Everything in the paid tiers maps to a moment fractional executives actually live through:

Conflict detection. A board meeting moves, and it now lands on another client's audit committee. Cross-calendar conflict detection flags it the moment both calendars are in view, not at 2:55 PM on the day.

Auto-block busy mirroring. When one client books you, the matching time shows as busy on your view of the others. Client A's EA sees a busy block, not "Client B board prep." You stay protective of every engagement without narrating any of them.

Share availability. A founder asks "when can we talk this week?" You send one set of open slots computed across every tenant, instead of cross-referencing four tabs in your head.

Time zones. The PE-backed client runs on Central time, the startup on Pacific. Every calendar renders in one coherent timeline.

Privacy Mode. When you screen share during a board session, your calendar shows a generic, unbranded look. The other companies you serve are your business, not the board's.

Meeting reminders. A reminder fires for every calendar, including the tenant tab you have not looked at since Monday.

What it does not do

Honest limits, because you would find them anyway. manyCalendars is a desktop browser extension only, so there is no phone app. Tab Sync reads what is visible in a tab you are signed into, which means it needs that tab. And it is read-only on the source: it will never write into a client tenant, which for a fractional executive is usually exactly the right default.

What it costs

Pro is 15 dollars a month, or 150 dollars a year (12.50 a month equivalent), and adds Tab Sync, meeting reminders, a custom work-week view, time zones, and .ics export. Premium is 29 dollars a month, or 290 dollars a year (24.17 a month equivalent), and adds Privacy Mode, conflict detection, auto-block busy mirroring, and share availability. Most fractional executives land on Premium, because conflict detection plus busy mirroring is the core of the job. Full details are on the pricing page.

The 14-day full trial starts when you install. No card, no account. Install manyCalendars free and see all of your companies in one view before your next board week.