I built 300+ free financial calculators and grew to 22K pages in 10 days — here's how

Hey IH 👋

I'm Jere, and I just launched CalcFi (https://calcfi.app) — a free financial calculator hub with 300+ tools covering retirement, tax, mortgage, FIRE, salary, crypto, and more.

The problem

Every time you Google something like "how much do I need to retire" or "mortgage payment calculator," you land on NerdWallet or Bankrate. The calculator is buried under 2,000 words of SEO filler, they want your email before showing results, and the "recommendation" is always a sponsored product.

I wanted something that just... works. Open page → use calculator → get answer → leave.

What I built

• 300+ calculators across 10+ categories (retirement, tax, mortgage, FIRE, salary guides, crypto, insurance, real estate, etc.)

• 22,000+ pages with localized data for all 50 US states and 160+ cities

• Embeddable widgets — any blogger or advisor can drop a calculator on their site with one line of code

• Zero signup, zero ads, zero email gates

Tech stack (for the nerds)

• Next.js 16 with full static generation — every single page is pre-built at deploy time

• React + TypeScript + Tailwind CSS

• Vercel for hosting (free tier handles it fine)

• Supabase for the email drip system

The entire site is SSG. 22,000+ pages build in about 4 minutes. Page loads are instant.

The pSEO play

This is where it gets interesting. The core product is 300+ calculator pages. But the real growth lever is programmatic SEO:

• Every calculator × every US state = 1,590 pages with real state-specific data (tax rates, cost of living, median home prices)

• 22 calculators × 163 cities = 1,793 pages

• 54 professions × 163 cities = 8,802 salary guide pages

• State comparison pages (Texas vs California, etc.)

• Spanish translations for 96 calculators

Each page has unique, genuinely useful content — not just the state name swapped in a template. Real data, real calculations, real value.

Growth strategy

No paid ads. Entirely organic:

1. SEO — 22K indexable pages targeting long-tail keywords

2. Embeds — free widgets for finance bloggers (they get a useful tool, we get a backlink)

3. Email outreach — 3 personalized emails/day to finance bloggers and resource page editors

4. Directory submissions — listed on 15+ directories so far

5. Content — blog posts targeting high-volume keywords (HYSA, savings rate, etc.)

Numbers (honest)

• Built in: ~10 days from zero to 22K pages live

• Revenue: $0 (pre-monetization)

• Costs: ~$0/month (Vercel free tier + Supabase free tier)

• Traffic: Too early to tell — waiting for Google to index 22K pages

• Monetization plan: Affiliate links (credit cards, savings accounts, investing platforms) + eventually display ads once traffic justifies it

What's next

• Waiting for Google to discover and index the 22K pages (IndexNow submitted, sitemaps live)

• Building backlinks through directory submissions and embed partnerships

• Writing 2-3 blog posts per week targeting high-volume finance keywords

• Tracking which calculator categories get the most organic traffic and doubling down

Lessons so far

1. pSEO works when the data is real. Swapping city names in a template is thin content. Pulling actual tax rates, median salaries, and cost-of-living indexes makes each page genuinely useful.

2. Embeddable widgets > "please link to us." Offering a free interactive tool converts way better than asking for a backlink.

3. Free tools can be a business. NerdWallet does $600M/year. Their calculators are the top of the funnel. Same model, smaller scale.

4. Ship fast, iterate later. 300 calculators in 10 days meant some rough edges. But live and imperfect beats perfect and invisible.

Ask

Would love feedback on the site. What calculators are missing? What would make you bookmark it? And if you run a finance blog — the embed widgets are free, hit me up.

🔗 https://calcfi.app

Happy to answer any questions about the pSEO strategy, tech stack, or the build process.