Free tools
The sums I do every week on Google Ads and paid social accounts, as calculators. The CTR, CPC, CPM and conversion rate tools compare your numbers with the Google Ads accounts I can see. No sign-up and nothing to download.
Start with the break-even ROAS calculator if you sell online, or the CPA calculator if you sell leads. Both give you the line a campaign has to beat. The CPC calculator then turns that line into the most you can pay per click.
Planning a new account? The budget calculator works back from a lead or sales goal. Tag every link with the UTM builder before it goes live, so the reports show which ad brought each visit.
For prompts, playbooks and Claude Code skills, see the free PPC tools library.