Google Analytics (GA4) vs Amplitude: Which Do You Actually Need?

This information is correct as of August 2026. Growth Method has made every attempt to ensure the accuracy and reliability of the information provided.

Most “GA4 vs Amplitude” comparisons treat these as rivals. They mostly aren’t. Google Analytics is a web and marketing analytics tool: sessions, channels, campaigns, conversions, wired into Google Ads. Amplitude is a product analytics platform: events, funnels, retention, cohorts, experimentation. The real question is not which is better; it is which job you need done, and whether GA4’s limits have started to bite.

A disclosure before we start: we tend to recommend PostHog when teams consolidate their analytics, largely because we believe it has the strongest AI and MCP story of any provider. Growth Method itself is agnostic (customers can connect any analytics provider via MCP), including both of these.

Quick verdict: keep GA4 for what it is genuinely good at: free campaign and acquisition reporting inside the Google ecosystem. Add Amplitude (or a rival) when you need to understand behaviour: where funnels leak, who retains, what to test next. If you are trying to make GA4 answer product questions with explorations and workarounds, you have already outgrown it.

GA4 vs Amplitude comparison

What GA4 is actually for

GA4 is the reporting layer of the Google advertising ecosystem, and judged on those terms it is unbeatable value: free at any traffic volume, natively linked to Google Ads for audiences and conversion import, and connected to Search Console. If your marketing runs on Google media, GA4 is not optional, and nothing here suggests removing it.

Its problems start when teams ask it to be a product analytics tool. Explorations sample once data volumes climb, cardinality limits collapse detailed reports into “(other)”, user-level retention analysis is shallow, and there is no session replay, no experimentation and no surveys. Simo Ahava, one of the most respected voices in the Google analytics community, put it plainly in his open letter about the platform:

What Amplitude is actually for

Amplitude was built for the questions GA4 fumbles: which behaviours predict retention, where activation funnels leak, which cohorts come back and why. Every plan now bundles session replay, feature and web experimentation, guides and surveys, and its AI features, priced on events (its old, hard-to-predict user-based pricing is gone). Cofounder Spenser Skates has been consistent about the founding aim since before the company listed:

What Amplitude is not is a media-buying tool. It imports ad spend, clicks and impressions from Google, Meta and LinkedIn, which is enough to put campaign cost next to product outcomes, but the Ads audience-sharing and conversion loops stay native to GA4.

Marketing analytics, product analytics, and the warehouse

This pairing is the clearest illustration of a distinction we push in every comparison: marketing analytics (channels, campaigns, spend, attribution) and product analytics (what users do once they arrive) are different jobs, and most teams need both done.

GA4 holds one unique card here: its free BigQuery export streams raw, unsampled event data into a warehouse you own, sidestepping every sampling and cardinality limit in the interface. Amplitude’s equivalent, warehouse-native Amplitude, is now a legacy feature closed to new customers. Our view is that every marketing team, regardless of size, should run a marketing data warehouse: GA4’s export makes BigQuery the natural start, with ad platform, CRM and product data joined alongside. Use GA4 and Amplitude as interfaces; own the data underneath. Route by job.

AI and MCP

Amplitude ships AI Agents that monitor dashboards, review replays and synthesise feedback, plus a hosted MCP server (we cover it in our Amplitude MCP guide) and AI Visibility for tracking how your brand appears in AI assistant answers. Google’s equivalent for GA4 is thinner: Gemini-powered insights in the interface, and an official MCP server that is experimental, self-hosted and read-only. For teams moving their analysis into AI assistants, Amplitude’s story is meaningfully ahead; GA4’s answer is, as ever, “export to BigQuery”.

How to choose

• Don’t frame it as either/or. Most B2B teams should run a free web analytics layer for media and campaigns, and a product analytics tool for behaviour.
• Let the questions decide. Write down the last ten questions your team asked of analytics. Channel and campaign questions point at GA4; behaviour and retention questions point at a product analytics tool.
• Set up the BigQuery export today regardless of anything else. It is free, it removes GA4’s sampling from the equation, and it future-proofs your marketing data warehouse.
• Shortlist the product analytics field. Compare Amplitude vs Mixpanel, PostHog vs Amplitude and PostHog vs Google Analytics before you commit.

Reviews

• G2: Google Analytics vs Amplitude

Final thoughts

GA4 is free, entrenched and genuinely good at Google-ecosystem marketing reporting; it is a weak product analytics tool wearing an event-based data model. Amplitude is a strong product analytics platform that cannot replace GA4’s Ads plumbing. Run the right tool for each job, export GA4 to BigQuery either way, and spend the time you save arguing about tools on the campaigns the data suggests.

About Growth Method

Analytics tells you what happened. It doesn’t decide what your team should do about it, or track whether the fix worked. That’s the gap Growth Method closes as the agentic marketing platform for B2B teams: connect your analytics stack (GA4, Amplitude or anything with an MCP server), and Growth Method turns insights into prioritised marketing campaigns, then closes the loop with data-driven attribution once they’re live. Your team gets a shared, first-party record of what you tried, what moved, and why.

Get started to see how it fits your stack.

Frequently asked questions

Is Amplitude better than Google Analytics?

They do different jobs. GA4 is a free web and marketing analytics tool wired into Google Ads, built for campaign and acquisition reporting. Amplitude is a product analytics platform built for funnels, retention, cohorts and experimentation. Amplitude is far better at behavioural analysis; GA4 remains the default for media buying and Google ecosystem reporting.

Can Amplitude replace Google Analytics?

For behavioural analysis, yes; entirely, usually not. Amplitude imports ad spend, clicks and impressions from Google, Meta and LinkedIn, and covers events, funnels and attribution. But teams buying Google Ads typically keep GA4 for its native Ads linkage, audience sharing and conversion export, and run Amplitude alongside it for product analytics.

Is Amplitude free like Google Analytics?

Amplitude has a free plan with 2M events per month, 10K session replays and its AI features, which is enough for many small teams. GA4 is free at any traffic volume, with paid Google Analytics 360 for enterprises. At scale Amplitude becomes a paid contract, so GA4 stays the cheaper tool; the question is whether it answers your behavioural questions.

Does Google Analytics do product analytics?

Only superficially. GA4 moved to an event-based model and offers funnel and path explorations, but reports are sampled at scale, retention analysis is limited, there is no session replay, no experimentation (Google Optimize was discontinued in 2023), and no surveys. Teams that need real product analytics pair GA4 with a tool like Amplitude, Mixpanel or PostHog.

Can GA4 or Amplitude replace a marketing data warehouse?

No, but GA4 has the best on-ramp: its free BigQuery export streams raw, unsampled event data into a warehouse you own. Amplitude’s warehouse-native mode is now legacy and closed to new customers. Every marketing team, regardless of size, should run a marketing data warehouse alongside whichever analytics tools it uses.