How we score
Every tool is scored on the same 100-point rubric (version 1.0 (2026-10-26)), computed in code from published prices and documented features. Each tool also gets the same short functional check, and anything that doesn't work takes points off. Affiliate links never affect scores or order. Prices are re-checked weekly.
Fairness rules
- Rubric fixed before scoring. Weights are the same for every tool. A change to the rubric re-scores every tool at once and is logged on the changelog.
- Affiliate links never affect scores, order or "best for" picks. Default order is score, then name.
- Same link treatment. Every tool gets one equally prominent link to its website. Where we have an affiliate link, that link is the affiliate one. Affiliate links are labelled and marked
rel="sponsored". - Affiliate programmes declared. Every affiliate programme we belong to is listed on the disclosure page.
- Evidence for every claim. Each price or limit links to the vendor page it came from, with the date checked and an archived copy where one exists. Every problem found in a functional check has evidence too.
- Public corrections. Anyone can submit a correction. Every submission and its outcome is logged publicly. Scores change only on evidence.
- Stale data is flagged. Any price or functional check not verified in the last 6 months shows "needs re-check".
The rubric
| Category | Points | Measures | What earns the points | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Price for value | 25 | Cost at three fixed usage levels. |
For each level we take the cheapest plan that covers it (billed monthly, or yearly ÷ 12 when no monthly price is published). Points = (cheapest tool + $5) ÷ (this tool + $5) × the points for that level. No plan fits, or custom pricing only: 0. |
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| Free plan | 14 | What you can do at $0. |
Adds: the lower of the monthly and per-event caps; a per-event cap is not multiplied by the number of events; "unlimited" counts as 30,000. Events: a per-day limit counts as 30 days' worth and a limit on active events counts as that number. An unstated limit earns nothing on its row. |
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| RSVP & subscription calendars | 14 | RSVP forms, waitlists and calendars people can subscribe to. |
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| Developer & automation | 14 | REST API, webhooks, Zapier and Make. |
Half points for a feature that is only on plans above $100 a month or with custom pricing. |
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| Limits & reliability | 17 | What happens at the cap, published status, and how long the service has run. |
Only one cap row and one age row apply. If cap behaviour is not documented, this category is left out of the score. |
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| Branding & privacy | 9 | "Powered by" removal, privacy commitments and independent security audit. |
Hosting on audited infrastructure ("SOC 2 hosted") does not count as an audit of the vendor. |
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| Help & docs | 7 | Public help content. |
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The score is the points a tool earns divided by the points available, shown out of 100, minus any penalties. A category is left out only when the vendor doesn't document what it measures (for example, what happens at the plan limit). A "Pending tasks to resolve" badge means we still have open questions about that tool's data to settle with the vendor.
Functional checks and penalties
We don't score tools on our own impressions. Instead, every ranked tool gets the same short check, and a pass changes nothing:
- Sign up on the free plan, or start a trial where there is no free plan.
- Create one test event (a non-UTC time zone, a description and a link) and add it to Google Calendar, Outlook and Apple Calendar.
- Run the tool's .ics file through an iCalendar (RFC 5545) validator.
Each problem found takes points off the final score, up to 20 points in total. Problems are listed on the tool's page with the date and evidence, and the penalty is removed once a re-check shows it fixed. If sign-up or login doesn't work at all, the tool is not ranked until it does.
| Problem | Penalty |
|---|---|
| Event lands with the wrong date, time or time zone (per calendar) | −5 |
| .ics file is invalid | −3 |
| Links stop working earlier than the vendor states | −5 |
| An advertised feature does not exist (each) | −3 |
| Sign-up or login doesn't work | Not ranked |
Readers and vendors can report a problem through the corrections form. We confirm it ourselves before applying a penalty.
Cost scenarios
Pricing is compared like for like at three fixed usage levels. For each, we take the cheapest plan billed monthly that covers it (or the yearly price ÷ 12 when no monthly price is published).
- Small: 4 events/month, 300 adds/month
- Growing: 20 events/month, 3,000 adds/month, RSVPs, Zapier
- High volume: 100 events/month, 30,000 adds/month, API, 5 seats
Where a vendor doesn't publish an add or event limit, we assume no cap and say so next to the result. Scenarios needing several seats only count plans with a published seat count.
"Best for" picks
- Best free add-to-calendar tool: Has a $0 plan. Ranked by our Free plan score (what you can do at $0). Tools level on this measure are shown as joint picks.
- Best add-to-calendar tool for high volume: Cheapest plan that covers 100 events/month, 30,000 adds/month, API access and 5 seats.
- Best add-to-calendar tool for developers: Has a documented REST API. Ranked by our Developer & automation score. Tools level on this measure are shown as joint picks. Free libraries are listed separately.
- Best add-to-calendar tool for webinars and events: Has RSVP forms. Ranked by our RSVP & subscription calendars score. Tools level on this measure are shown as joint picks.
- Best tool for subscribable event calendars: Has subscription calendars and an embeddable calendar for your website. Ranked by the monthly price of the cheapest plan that includes both. Tools level on this measure are shown as joint picks.
- Best add-to-calendar tool for teams: Has a plan with unlimited team members. Ranked by the monthly price of the cheapest such plan. Tools level on this measure are shown as joint picks.
- Most established add-to-calendar vendor: Has an independent security audit of the vendor (SOC 2 or ISO 27001) first, then the most years in operation, counting earlier names. Tools level on this measure are shown as joint picks.
Update schedule
- Weekly: an automated job screenshots every pricing page and flags any change. A person confirms each change before it goes live, and it's logged on the changelog.
- Every 6 months: the functional check is repeated for every tool, or sooner when a vendor ships a major change or someone reports a problem.