# c15t vs Usercentrics: cookie banner speed and features

On desktop, c15t showed its banner sooner, in a median 60 ms against 672 ms for Usercentrics. Their delay to the main content was about the same. The 95% intervals overlap. Both held trackers back in every check. Per vendor docs, only c15t offers open-source code and self-hosting. Per vendor docs, only Usercentrics offers a Google-certified CMP.

We measured both in the same run, in a Next.js app. We measured each against the same page without a consent manager. They also share Script tag, React, Nuxt, Astro, TanStack Start integrations.

## Which is faster on desktop?

Desktop profile: 1365 × 768 · No CPU slowdown · 12.5 MB/s, no added latency.

| Question | c15t | Usercentrics | Difference |
| --- | --- | --- | --- |
| How fast does the banner appear? | 60 ms | 672 ms | c15t’s banner appeared 612 ms sooner. |
| Does it slow the page down? | +16 ms (95% interval 8 ms to 40 ms) | No measurable change | About the same. The 95% intervals overlap. |
| How fast does a click respond? | 16 ms | 16 ms | About the same. They are less than 16 ms apart. |
| Does it block trackers until consent? | 4 of 4 checks passed | 4 of 4 checks passed | Both held trackers back in every check. |
| How much does it add to the page? | +112 KB (95% interval: 112 KB) | +164 KB (95% interval: 164 KB) | c15t added 52 KB less to the first load. |

## Which is faster on mobile?

Mobile (emulated) profile: 390 × 844, DPR 3 · Mid-tier phone CPU (4× slowdown) · 200 KB/s, 150 ms latency.

On emulated mobile, c15t showed its banner sooner, in a median 240 ms against 4.16 s for Usercentrics. c15t delayed the main content 436 ms less. Both held trackers back in every check. Per vendor docs, only c15t offers open-source code and self-hosting. Per vendor docs, only Usercentrics offers a Google-certified CMP.

| Question | c15t | Usercentrics | Difference |
| --- | --- | --- | --- |
| How fast does the banner appear? | 240 ms | 4.16 s | c15t’s banner appeared 3.92 s sooner. |
| Does it slow the page down? | +408 ms (95% interval 396 ms to 420 ms) | +844 ms (95% interval 836 ms to 864 ms) | c15t delayed the main content 436 ms less. |
| How fast does a click respond? | 32 ms | Under 16 ms | Usercentrics responded at least 16 ms sooner. Both are under 200 ms, which feels instant. |
| Does it block trackers until consent? | 4 of 4 checks passed | 4 of 4 checks passed | Both held trackers back in every check. |
| How much does it add to the page? | +112 KB (95% interval: 112 KB) | +164 KB (95% interval: 164 KB) | c15t added 52 KB less to the first load. |

## Which features differ?

| Feature | c15t | Usercentrics |
| --- | --- | --- |
| IAB TCF | Per vendor docs | Per vendor docs (Pro plan and up) |
| IAB GPP | Per vendor docs (GPP 1.1) | Per vendor docs (v3 script tag) |
| Google Consent Mode v2 | Per vendor docs | Per vendor docs |
| Google-certified CMP | Not supported (Not on Google’s list) | Per vendor docs |
| Global Privacy Control | Per vendor docs | Per vendor docs |
| Geo-targeted banners | Per vendor docs | Per vendor docs (Plus plan and up) |
| Script blocking | Per vendor docs | Per vendor docs (Paid plans) |
| Consent records | Per vendor docs (With a backend) | Per vendor docs (Kept 12 months) |
| Cookie scanning | Per vendor docs (Via Inth Website Audit) | Per vendor docs |
| Open source | Per vendor docs (Apache-2.0) | Not supported (Commercial licence) |
| Self-hostable | Per vendor docs | Not supported (Hosted backend) |
| Headless UI | Per vendor docs | Per vendor docs |
| TypeScript types | Per vendor docs | Per vendor docs |
| Free tier | Per vendor docs (Open source; hosted free plan) | Per vendor docs (1,000 sessions a month) |
| Script tag | Per vendor docs | Per vendor docs |
| React SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |
| Next.js SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |
| Vue SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |
| Nuxt SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |
| Svelte SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |
| SvelteKit SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |
| Astro SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |
| TanStack Start SDK | Per vendor docs (First-party SDK) | Not supported (Script tag only) |

## Which should you choose?

### Choose c15t if

- You want open-source code and self-hosting
- You want a first-party SDK for React, Next.js, Vue, Nuxt, Svelte, SvelteKit, Astro and TanStack Start
- A fast banner matters to you: c15t’s banner appeared 612 ms sooner
- Page weight matters to you: c15t added 52 KB less to the first load

### Choose Usercentrics if

- You need a Google-certified CMP

## Questions about this pair

### Is Usercentrics slower than c15t?

On the desktop profile, c15t’s banner appeared in a median 60 ms and Usercentrics’ in 672 ms. Their delay to the main content was about the same. The 95% intervals overlap.

### Does c15t support Google-certified CMP like Usercentrics?

No, per vendor docs. Usercentrics documents Google-certified CMP support. c15t does not.

### Do c15t and Usercentrics block trackers before consent?

Both held trackers back in every check. Each check loads the page. Then it looks for trackers that ran, cookies that the page set or data that left the page before the visitor chose.

## Related comparisons

- [c15t vs OneTrust](https://cookiebench.com/compare/c15t-vs-onetrust.md)
- [c15t vs CookieYes](https://cookiebench.com/compare/c15t-vs-cookieyes.md)
- [c15t vs Didomi](https://cookiebench.com/compare/c15t-vs-didomi.md)
- [c15t vs Osano](https://cookiebench.com/compare/c15t-vs-osano.md)
- [c15t vs iubenda](https://cookiebench.com/compare/c15t-vs-iubenda.md)
- [c15t vs Ketch](https://cookiebench.com/compare/c15t-vs-ketch.md)

Methodology [cookiebench-v3.2.4](https://cookiebench.com/methodology). inth, the team behind c15t, maintains CookieBench. c15t is one of the consent managers we measure ([disclosure](https://cookiebench.com/methodology)). Feature support comes from vendor documentation unless a row says "Verified by test".