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Avum vs OneCal: Pricing, Features and Which Calendar Sync Tool to Choose
OneCal and Avum both keep Google, Outlook, iCloud and CalDAV calendars aligned with private busy copies. The real difference is how each one charges you. OneCal prices by the calendar. Avum prices by connected account and sets no plan limit on the calendars inside each account. That gap widens as your setup grows: Avum's largest plan costs $10 a month, while OneCal's Premium plan costs $30.
Published by Avum. Prices and features were checked against each vendor's official pages on November 2, 2026. Sources are listed under each table.
Avum vs OneCal at a glance
| Avum | OneCal | |
|---|---|---|
| Pricing | ||
| Entry plan, billed monthly | $5 / month | $6 / month |
| Largest individual plan, billed monthly | $10 / month | $30 / month |
| Largest individual plan, billed yearly | $100 / year | $300 / year |
| What the plan limit counts | Connected accounts (2, 4 or 10) | Calendars (2, 5 or 50) |
| Calendars inside each account | No plan limit | Each one counts |
| Free trial | 30 days, no card | 14 days, no card |
| Calendars | ||
| Google, Outlook and iCloud | Yes | Yes |
| CalDAV servers | Yes | Yes |
| ICS feed as a source | Direct connection | Via a Google or Outlook subscription |
| How far ahead Outlook events sync | Up to 4 years | 3 months |
| Sync control | ||
| Choose which event details are copied | Yes | Yes |
| Replace titles, hide notes and location | Yes | Yes |
| Several sources and destinations in one rule | Yes | Yes |
| Filter by color or attendance status | Yes | Yes |
| Filter by weekday, hour or date range | Yes | Not advertised |
| Conditional blocks and formula or JavaScript transforms | Plus and Premium | Not advertised |
| Beyond sync | ||
| Combined calendar view | Avum Calendar, up to 3 time zones | Yes |
| Booking and scheduling links | No | Yes |
| AI assistant | No | Yes |
| SSO and admin-managed accounts | No | Yes |
Sources: OneCal pricing, what OneCal syncs, OneCal ICS help, OneCal's own comparison page for its filter options, and Avum pricing. Prices are in US dollars for one user. Features can change; check both vendors before you buy.
Pricing: accounts versus calendars
Most people do not have one calendar per account. A Google account usually holds a primary calendar plus family, shared or project calendars. A consultant's client accounts often hold more than one calendar each.
OneCal counts every calendar you import. Its Starter plan covers two, Essential covers five, and anything beyond five moves you to the $30 Premium plan. Avum counts the accounts you connect. Everything inside those accounts is available to your rules, with no plan limit on the number of calendars.
Here is what that means for three common setups, using monthly billing:
| Avum | OneCal | |
|---|---|---|
| Personal Google and work Outlook, two calendars | $5 (Base) | $6 (Starter) |
| Four client accounts, eight calendars between them | $7 (Plus) | $30 (Premium) |
| Ten accounts, twenty calendars | $10 (Premium) | $30 (Premium) |
Based on each vendor's monthly price for a single user. If you sync only four of the eight calendars in the second setup, OneCal's Essential plan at $12 a month applies. Avum's price does not change. On yearly billing the figures are $50, $70 and $100 per year for Avum against $60, $120 and $300 for OneCal.
On a yearly plan, the consultant in the middle row pays $70 for Avum and $300 for OneCal's Premium tier. Even the most favourable OneCal option for that setup, syncing only four calendars on Essential, costs $120 a year.
The details that decide whether sync can be trusted
Copies that keep personal details out of work
For a personal Google appointment that must block time in work Outlook, both products can copy the time with a neutral title. In Avum you set this per destination in a Sync Rule: replace the title with “Busy”, leave out the description and location, and mark the copy busy or private. A different destination can receive fuller details from the same source.
Check the whole copy, not just the title. A meeting link or address left in the notes can still identify the appointment. The busy-only copying checklist lists every field to inspect.
Filters that decide what gets copied at all
OneCal's comparison page lists exclusion by color and by RSVP status. Avum supports both, and adds filters for availability, date range, weekdays and specific hours. That matters when only weekday daytime commitments should reach a client calendar, or when weekend plans should never appear at work.
On Plus and Premium, Avum's advanced settings add ordered conditional blocks and formula- or JavaScript-based transformations. A rule can then, for example, label copies differently depending on which calendar they came from.
Appointments booked far ahead
OneCal documents a rolling window of one year ahead for Google and iCloud and three months ahead for Outlook. A conference or surgery booked four months out in Outlook will not reach its other calendars until it enters that window. Avum's Outlook sync reads up to four years ahead, so far-future commitments block time as soon as you create them.
ICS timetables, rotas and feeds
Avum connects an ICS link directly as a read-only source. OneCal's documentation asks you to subscribe to the feed in Google or Outlook first and sync from there. That extra step adds the provider's own refresh schedule, which can be several hours, before any copy is updated. For a university timetable or a shift rota that changes at short notice, a direct source removes one delay from the chain.
Where OneCal is the stronger choice
OneCal is a broader product, and for some people that is worth paying for. It includes unlimited scheduling links, group scheduling, an AI assistant, an MCP server, team plans with SSO and SCIM, and dedicated support on Premium. If you would otherwise buy Calendly or a similar booking tool, add that saving to OneCal's side before comparing prices.
Avum is deliberately narrower. It does not offer booking pages, and it is built for individuals rather than managed teams.
Choose Avum if…
- You need reliable sync and do not need booking pages
- Your accounts hold more than one calendar each
- You want filters by weekday, hour or date range
- You book Outlook events more than three months ahead
- You want a month to test it on your real calendars
Choose OneCal if…
- You want sync and booking links in one product
- You need an AI scheduling assistant
- Your company requires SSO, SCIM or admin-managed seats
- You sync only a couple of calendars and value the extras
Switching from OneCal to Avum
Run only one service per direction. Before enabling Avum, pause the matching OneCal sync and remove its clones so the destination does not end up with two busy blocks for the same appointment. Switching sync tools without duplicates walks through the order.
Then test one direction with a new event, a reschedule, a recurring exception and a cancellation. The calendar sync test checklist covers each case.