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Homepage vs Cart — The Session Penalty

22,634 WooCommerce stores with both cached homepage + cart measurements

Median Homepage TTFB

410ms

Cached (no cookies)

Median Cart TTFB

1008ms

With session cookies

Median Slowdown

2.15x

Cart vs homepage

Sites Tested

22,634

With both measurements

Cart pages are 2.15x slower than homepage for the median store

67.1% of stores (15,189) deliver a slower cart experience than their homepage

11,688 sites (51.6%) have a severe penalty — cart is 2x+ slower than homepage

Slowdown Distribution

Bucket	Count	%	Interpretation
< 1x	7,435	32.8%	Cart faster than homepage (rare)
1-1.5x	2,017	8.9%	Minimal penalty
1.5-2x	1,494	6.6%	Noticeable slowdown
2-3x	2,244	9.9%	Significant penalty
3-5x	2,884	12.7%	Severe penalty
> 5x	6,560	29.0%	Critical

Slowdown Distribution

Homepage vs Cart at Key Percentiles

The gap between cached homepage and cart TTFB grows at higher percentiles

Homepage TTFB vs Cart TTFB

Points above the diagonal = cart is slower than homepage (expected for most stores)

Percentile Comparison

Homepage and cart columns are independent distributions. Slowdown is the percentile of the per-site ratio (cart / homepage).

Percentile	Homepage (cached)	Cart (uncached)	Slowdown
p10	101ms	409ms	0.52x
p25	188ms	640ms	0.82x
p50 (median)	410ms	1008ms	2.15x
p75	1034ms	1619ms	5.91x
p90	2144ms	2486ms	13.23x

Methodology

Homepage TTFB is measured in a clean browser session without any cookies — this captures the true cached/CDN response time as a regular visitor would experience.

Cart TTFB is measured with WooCommerce session cookies set (woocommerce_items_in_cart, woocommerce_cart_hash, wp_woocommerce_session_*), which forces the server to bypass page cache and generate a dynamic, personalized response.

Slowdown = Cart TTFB / Homepage TTFB. A value of 2.0x means the cart page takes twice as long to respond as the cached homepage.

The "session penalty" measures the performance cost of transitioning from an anonymous visitor (who benefits from page cache) to an active shopper (whose requests bypass cache). This penalty is what every potential customer experiences the moment they add an item to their cart.