Website: unique visitors, pages per session, time on site, conversion rate on key actions (donations, signups, contact forms). Google Analytics 4 is free and, once set up properly, gives you what you need.
Email: click-through rate, conversion rate, unsubscribe rate, list growth. As noted above, open rates are less reliable than they used to be.
Social media: engagement rate (not follower count), click-throughs to your website, and direct conversions (phone calls, form completions or emails) – particularly if you’re running a fundraising campaign. Follower count is a vanity metric; engagement tells you whether people actually care.
SEO: track your organic traffic, the keywords you’re targeting, your number of backlinks and your domain authority. The number of users arriving at your site by organic search (Google etc) is the most important SEO metric – and whether these visits are generating conversions.
Overall: track where your donors, volunteers, and supporters first found you. A simple “how did you hear about us?” question on forms gives you attribution data that’s more useful than most analytics dashboards.
The goal isn’t perfect measurement. It’s knowing enough to do more of what works and less of what doesn’t. We’ve worked with nonprofits that were pouring hours into channels that generated zero conversions, simply because nobody had checked. A monthly 15-minute review of your key metrics will save you from that.