Google algorithm updates: the two records, and how to use the dates on your own traffic
Google's Search Status Dashboard covers confirmed ranking updates from November 2021; Moz's history runs from 2000 and logs the unconfirmed days too. Here is what each is for, the rollout windows, and the comparison method Google asks for.
Published by AI Knows Us · Updated 13 October 2026
There are two records of Google algorithm updates, and they answer different questions. Google keeps the official one: the ranking history on the Search Status Dashboard lists every confirmed ranking update with a start date and a duration, and its ranking entries run back to November 2021. Moz keeps the best known independent one, Google Algorithm Updates and History, which covers 2000 to the present, names the historical updates that predate Google's own list, and adds the days when rankings clearly moved and Google said nothing. Use Google's record for any date you are going to act on. Use Moz's for anything before late 2021, for the names people still use in meetings, and for the unconfirmed volatility.
The two records, side by side
| Google Search Status Dashboard | Moz's algorithm history | |
|---|---|---|
| Coverage | Confirmed ranking updates, November 2021 onwards | 2000 to the present, confirmed and unconfirmed |
| What each entry gives | Name, start date, duration, and whether it is still rolling out | Name, date, a description, a volatility reading and links to analysis |
| Best used for | Aligning your own traffic dates to a rollout window | Context, history, and explaining a day Google never named |
| What it will not do | Tell you what changed inside the update | Serve as the authority on a date you are making a decision from |
Google's own list, and the field most people skip
Each row on the dashboard carries a duration, and that is the field that decides how you read your own analytics. A core update is not a moment, it is a window, and the windows are long and uneven.
| Core update | Started | Duration |
|---|---|---|
| March 2024 core update | 5 March 2024 | 45 days |
| August 2024 core update | 15 August 2024 | 19 days, 4 hours |
| November 2024 core update | 11 November 2024 | 23 days, 13 hours |
| December 2024 core update | 12 December 2024 | 6 days, 4 hours |
| March 2025 core update | 13 March 2025 | 13 days, 21 hours |
| June 2025 core update | 30 June 2025 | 16 days, 18 hours |
| December 2025 core update | 11 December 2025 | 18 days, 2 hours |
| March 2026 core update | 27 March 2026 | 12 days, 4 hours |
| May 2026 core update | 21 May 2026 | 11 days, 21 hours |
Spam updates, reviews updates and Discover updates get their own rows, and they overlap core updates regularly. The dashboard shows three spam updates in 2026 alone, in June, August and September, with the September one running 13 days and 16 hours. If your traffic moved in a week with two rollouts in it, the honest answer is that you cannot attribute it to one of them, and that is a useful thing to know before somebody asks you to fix it.
The named updates people still bring up
Everything in this list predates Google's own dashboard history, which is exactly why a third party record still matters. The dates are the ones recorded in Moz's history.
- Hummingbird, announced around 20 August 2013. A rewrite of how queries were interpreted rather than a filter. Our page on what Hummingbird changed covers why it still shapes how pages are written.
- Panda, a series through 2011 to 2015, with Panda 4.0 on 19 May 2014. Thin and duplicated content.
- Penguin, a series from 2012, with Penguin 4.0 announced on 23 September 2016, at which point Google described it as real time and part of the core algorithm. See what Penguin was and how link problems are handled now.
- Pigeon, 24 July 2014. Local results.
- The mobile friendly update, 22 April 2015, the one the industry nicknamed Mobilegeddon, followed by the mobile first index rollout from 26 March 2018.
- RankBrain, 26 October 2015, and BERT, 22 October 2019. Both are language understanding systems rather than ranking filters.
- The helpful content update, 25 August 2022. Moz's entry for the March 2024 core update records that it folded the helpful content work into the core algorithms, and that Google said the changes would reduce unhelpful content in results by 40 percent.
What the independent record adds that the official one cannot
Moz pairs its entries with a volatility reading taken from its own measurement of ranking movement, which lets it log days Google never acknowledged. Two examples from its history show why that is worth having: it recorded its highest ever reading of 149.1 during August 2024, in a period when the Status Dashboard was also reporting an ongoing ranking issue alongside the core update, and it recorded an unexplained reading of 175 on 5 March 2026 with no confirmation from Google at all.
The practical use is narrow and real. When your traffic drops on a day with no confirmed update, a volatility record tells you whether the whole results landscape moved or only you did. Those are completely different problems, and they have completely different fixes.
How to use a dated list against your own traffic
Google's guidance on core updates sets out the method, and it is stricter about timing than most reporting cycles are:
- Confirm the update has finished rolling out, using the start and end dates on the status dashboard.
- Wait at least a full week after it completes before analysing anything.
- Compare that week with a week before the rollout started, so you are comparing two settled periods rather than one settled and one mid flight.
- Review your top pages and queries and size the movement. Google's own threshold: a small drop, position two to four, calls for no drastic action, and it specifically recommends not changing content that is already performing well. A large drop, position four to twenty nine, earns a deeper assessment.
- Separate the search types, so you know whether you lost web results, images, video or news rather than guessing.
Then write the finding down in one sentence before you touch the site. For the fuller diagnostic when the cause is not an update at all, work through the traffic drop checklist in order, and for the case where the cause is a manual action rather than an algorithm, see diagnosing and recovering from a penalty.
Three ways the history gets misused
- Attributing a change to an unconfirmed spike. A volatility reading says the landscape moved. It does not say what moved, and treating it as a named update invents a cause.
- Quick fixes. Google asks you to avoid removing a page element because you heard it was bad for SEO, and calls deleting content a last resort, only for content that cannot be salvaged.
- Reading the announcement date as the impact date. With rollouts running from six days to forty five, the day the blog post went up is rarely the day your rankings moved.
Keep your own dated change log alongside the public one. One line per change, with the date. A site with a change log can answer what happened; a site without one has to guess for the rest of its life. Where to read each announcement first, and what to do in the week afterwards, is covered in our page on where to read the latest SEO updates.
Questions about Google's update history
Is there an official list of Google algorithm updates?
Yes. The ranking history on the Search Status Dashboard is Google's own record, with start dates, durations and rollout status. It covers confirmed updates from November 2021 onwards.
How many updates does Google make in a year?
A handful are announced, typically a few core updates and a few spam updates, and Google states that it makes smaller changes continually without announcing them because they are not widely noticeable.
Why do third party histories list updates Google never confirmed?
Because they are measuring ranking movement rather than reporting announcements. An unconfirmed entry is a record that something changed across many results on that date, which is genuinely useful context and is not the same as a named update.
How far back does the record go?
Google's ranking entries start in November 2021. Moz's history runs from 2000, which is where the Panda, Penguin, Hummingbird and Pigeon era dates come from.
How long after an update should I expect a recovery?
Google says improvements can take effect in a few days but may take several months for its systems to confirm that the site as a whole has improved, and that you do not have to wait for the next big core update to see an effect. Plan the work on a quarter, not on a fortnight.
A record exists because somebody decided to publish one
The reason this history is useful is mundane: dates, durations, and a public note of what changed, which lets you line your own numbers up against a known event. That discipline exists for ranking and nowhere else yet. When a buyer asks ChatGPT, Gemini, Perplexity or Claude who to use in your category, the set of companies named shifts as the web those systems read shifts, and there is no dashboard, no start date and no duration to compare your numbers against. The only version of this history that will ever exist for that surface is the one you keep yourself: the same question, asked on a schedule, with the names and the cited sources written down each time. AI Knows Us keeps that record for the companies that want it: aiknowsus.com.