Performance budget calculator.
A performance budget is a ceiling on how heavy your pages can get. Set a target load time and the connection you want it to hold up on, and this shows roughly how much page weight — images, scripts, fonts, everything — you can afford before you blow past it.
Roughly how that budget could be spent:
How to use this
The calculation is deliberately simple: it estimates how many kilobytes can transfer within your target time on the chosen connection, allowing for real-world overheads (latency, protocol inefficiency, and the fact that not all bytes arrive at full speed). It's a planning guide, not a precise physics model — but it gives you a concrete number to design against, which is the whole point of a budget.
To check what your site actually weighs today, run it through PageSpeed Insights or our website checker, then compare against your budget. If you're over, the speed optimisation guide covers where to cut — usually images first. For why load time matters this much, see Core Web Vitals.
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