Amplitude Alternatives in 2026: What PostHog, Mixpanel, Heap, and GA4 Actually Cost

Amplitude alternatives get compared on feature checklists more often than on the number that actually changes a budget: the bill. That is the wrong axis to lead with, because on 2026-07-12 two of the five tools in this category - Amplitude and Heap - do not publish what a team pays once free-tier usage is exceeded. The other three - PostHog, Mixpanel, and GA4 - do, and the gap between them is large enough to change a decision on its own.

This guide pulls exact numbers from each vendor's live pricing page, runs a real monthly-cost model at a shared usage level, and calls out plainly which vendors cannot be modeled from public information. The goal is a decision a team can defend later, not a features table that reads the same on every analytics comparison site.

Quick Decision

If a team's usage sits inside the free tier for its shortlisted tool, the pricing question is moot and the decision should run on features and workflow fit instead - see the PostHog review for that comparison. Past the free tier, only PostHog and Mixpanel let a team compute a real number in advance; Amplitude and Heap require signing up or contacting sales to find out. That asymmetry, not any single feature, is the first thing to weigh.

What Each Vendor Actually Publishes

Two of these rows are more useful for what they refuse to say than for what they say. Amplitude's page states outright that Plus "starts at $0" and lists an event ceiling (70M/month) but shows no per-event or per-MTU dollar figure anywhere on the page - not even in a calculator range. Heap does the same thing one tier earlier: everything past the 10,000-session free plan is "custom pricing," full stop. A vendor that will not publish a rate card is not necessarily worse - Amplitude and Heap may legitimately negotiate volume discounts sales-led vendors with published rates do not offer - but it does mean a team cannot budget before talking to a salesperson, and that is a real cost in time even before money changes hands.

The Real Monthly Bill at 5M Events

Rather than compare list prices in the abstract, here is what 5,000,000 monthly events actually costs on the two vendors that publish enough to calculate it, plus the two vendors where it costs nothing regardless of volume.

PostHog (declining tiered rate, product analytics only): the first 1M events are free; the next 1M fall in the $0.00005/event band ($50.00); the remaining 3M fall in the $0.0000343/event band ($102.90). Total: ≈$152.90/month.

Mixpanel (flat rate after free tier): the first 1M events are free; the remaining 4,000,000 events bill at $0.28 per 1,000 events, or 4,000 × $0.28. Total: ≈$1,120.00/month.

GA4 standard: $0/month at this volume - the standard property has no per-event bill, only a 100,000-events-per-user-per-day ceiling that a normal product will not approach in aggregate.

Amplitude and Heap: not calculable from public pricing. Amplitude's free tier caps at 2M events, so a 5M-event team is already into the Plus tier's undisclosed usage-based pricing. Heap's free tier caps at 10,000 sessions (a different unit than events, which makes a direct comparison harder on its own), and every paid tier above that is custom-quoted.

The roughly 7x gap between PostHog and Mixpanel at identical volume is not a rounding difference - it is the entire monthly analytics line item for a small team, and it comes from one structural choice: PostHog's rate declines as volume grows while Mixpanel's stays flat at $0.28/1,000 events, with the page only noting that a volume discount is available without publishing the discounted rate. A team doing significantly more than 5M events a month should re-run this math at its real number, because the gap compounds - PostHog's rate keeps falling through six declining tiers down to $0.000009/event past 250M events, while Mixpanel's public page does not disclose where or how far its own step-down goes.

For a deeper breakdown of PostHog's full multi-product bill - including session replay and feature-flag pricing, which are metered separately from the analytics-events number used above - see PostHog Pricing 2026: What Usage-Based Pay-As-You-Go Actually Costs, which models 1, 5, and 10-seat scenarios in full.

Where Each Tool Actually Fits

Amplitude is the strongest pick when a team already runs product experimentation and behavioral cohorting as core workflows and is comfortable negotiating price directly - its free tier (2M events, 10K session replays, AI-assisted analysis) is also the most generous of the five on paper, which makes it a reasonable on-ramp for a team that expects to negotiate before it needs to pay. It is the wrong pick for a team that needs to forecast a SaaS budget line item without a sales call.

Mixpanel fits teams under roughly 1M events a month, where it is free with unlimited seats, or teams for whom the Growth plan's flat, easy-to-explain-to-finance rate ($0.28/1K events) is worth paying a premium over PostHog's more complex declining-tier math. Its startup program (first year free for companies under five years old with under $8M raised) is also broader than Amplitude's scholarship, which caps at $10M in funding and 20 employees and only applies to the Growth tier.

PostHog is the strongest pick on pure per-event economics past the free tier, and the only one of the three transparent vendors that also bundles session replay, feature flags, and surveys into the same metered platform rather than a separate product. It is the right call for an engineering-led team willing to own usage discipline (billing limits, replay sampling) in exchange for the lowest modeled bill at moderate-to-high volume. See the Mixpanel alternatives roundup if PostHog's usage-based model specifically is the sticking point.

Heap fits a narrower case: teams that want autocapture (no manual event instrumentation) and are already comfortable negotiating enterprise SaaS contracts, since nothing past the 10,000-session free tier has a public number to plan against.

GA4 is the right default when a team needs basic acquisition and engagement reporting tied to ad platforms and does not need session replay, feature flags, or a dedicated product-analytics workspace - and needs it at $0 regardless of scale. It is the wrong tool the moment a team's actual job is behavioral cohort analysis or in-product experimentation, which is what the other four are built for and GA4 is not.

Decision Checklist

Before picking one of these five, confirm:

• Real monthly event volume, not a rough guess - the PostHog/Mixpanel gap above only holds at 5M events; recompute at a team's actual number, since PostHog's declining tiers change the math more at higher volume.
• Whether a sales conversation is acceptable - Amplitude and Heap require one to get a real price past the free tier; PostHog and Mixpanel do not.
• Whether session replay and feature flags need to live in the same platform as analytics - PostHog and Amplitude bundle these; Mixpanel, Heap, and GA4 do not (or meter/limit them more narrowly).
• Whether GA4's ad-platform integration matters more than product-analytics depth - if marketing attribution is the primary use case, GA4's $0 cost is hard to beat and the other four are solving a different problem.

Bottom Line

The honest finding in this category is not which tool "wins" - it is that two of the five leading Amplitude alternatives will not tell a prospective buyer what they cost until that buyer talks to sales, while three will. At a shared 5M-event benchmark, PostHog costs about $153/month and Mixpanel costs about $1,120/month for the same workload, a gap driven entirely by rate structure rather than features. GA4 stays free but is not a substitute for the other four's core product-analytics workflow. Amplitude and Heap may still be the right technical fit for some teams - but that decision will be made with a sales rep, not with a pricing page.

Official Links

• Amplitude pricing
• Mixpanel pricing
• PostHog pricing
• Heap pricing
• Google Analytics 4 event limits