# What a 500-page crawl costs, and why Lighthouse is opt-in > A crawled page costs a credit; a performance check costs 50. Why the check runs on a sample of ten pages, so audits fit a month. Source: https://netweft.com/blog/what-a-crawl-costs Updated: 2026-10-17 **A crawled page costs one credit, so a 500-page crawl is 500 credits. A Lighthouse pass costs 50 credits a page, so netweft measures a sample, the start URL and one page per URL shape up to 10, adding at most 500 credits. It is opt-in per audit.** The [site audit](/features/site-audit) is the one part of netweft that does not buy its data. The crawler is ours, so a crawled page costs compute and bandwidth rather than a vendor call. That makes it cheap, and it makes one adjacent decision expensive. ## The two numbers A crawled page is one credit. Five hundred pages, five hundred credits — about five cents of infrastructure at the basis the credit is priced on. A performance check on a page — the [Core Web Vitals](/glossary/core-web-vitals) pass — is 50 credits. Same page, 50 times the cost, because that one is a vendor call. Measured on every page of a five-hundred-page crawl, the run would go from 500 credits to 25,500, 20% of the 125,000 a Pro workspace gets in a month. So netweft does not measure every page. It measures the start URL, then one page per URL shape it has not measured yet, up to 10. The most a performance pass can add to any audit is 500 credits. ## Why not just make it cheaper Because we would be lying about what it costs. The rate card is derived from the vendor rate card at a fixed basis; moving one line to make it look better would either move the margin or move the truth. Measuring fewer pages changes neither: each page measured still costs what the vendor charges. ## What to do instead The useful shape is not "audit everything, measure everything". It is: **Crawl wide.** The structural findings — broken links, missing [canonicals](/glossary/canonical-url), redirect chains, thin or duplicated titles — come from the crawl itself, at one credit a page. Run that across the whole site as often as you like, subject to your own [crawl budget](/glossary/crawl-budget) rather than ours. **Measure narrow.** Performance is a page-template problem far more often than a page problem, which is why the sample is one page per URL shape. Ten pages that represent your templates tell you almost everything a five-hundred-page sweep would, and the sample keeps the pass at 500 credits at most. The [template guide](/blog/auditing-by-template) shows how the sample is chosen. **Re-measure on change.** A performance check is worth spending after a deployment that touched the template, not on a schedule that touches nothing. ## Severity is the other half An audit that returns four hundred equal-weight findings is a backlog nobody starts. netweft classifies findings by severity so the list has a top, which is the difference between a report and a morning's work. The crawl respects [`robots.txt`](/glossary/robots-txt), which is worth saying plainly: netweft will not fetch what you have asked crawlers not to fetch, including on your own site. If a section is disallowed and you want it audited, the fix is in the robots file, not in a setting here. ## The general rule Where a check is cheap because we run it, run it broadly. Where a check is expensive because someone else runs it, run it where it changes a decision. The [rate card](/pricing) is published in full precisely so that this is a calculation you can do before the run rather than a number you find afterwards. The wider argument for pricing lookups this way is in [what an SEO data lookup actually costs](/blog/what-an-seo-lookup-costs).