Over the past month, I built Landolio — a collection of 25 free browser-based tools for UK freelancers and sole traders. No sign-ups, no ads, no data collection. Everything runs in your browser with localStorage.
Here's what I built, why, and what I'd do differently.
The Tools
Tax & Money
- Day Rate Calculator — enter your target salary, get your day rate after tax and NI
- Self-Employed Tax Calculator — full Income Tax + NI + student loan breakdown
- VAT Threshold Calculator — check if you need to register based on rolling turnover
- Business Expense Tracker — track by HMRC category, export CSV
- Cash Flow Forecast — month-by-month projection with gap alerts
- Mileage Allowance Calculator — HMRC rates for cars, vans, bikes
- Profit Margin Calculator — what you actually take home per pound invoiced
Invoicing
- Free Invoice Template UK — 3 styles, VAT toggle, PDF download
- Invoice Generator — fill in, preview, save as PDF
- Payment Reminder Generator — friendly, firm, or final notice emails
- Late Payment Interest Calculator — statutory interest under UK law
- Late Payment Letter Generator — professional chase letters
Making Tax Digital
- MTD Readiness Checker — does MTD apply to you? 2-minute quiz
- MTD Penalty Calculator — new points-based penalty system
- MTD Cost Calculator — estimate your annual compliance costs
Business Management
- Client & Project Tracker — track clients, projects, invoices with dashboard
- Contract Generator — UK-compliant freelance contracts
- Project Quote Calculator — phase-based pricing with scope creep buffer
...and more.
What I Learned
1. Free tools are incredible SEO magnets
Blog posts get impressions, but interactive tools get engagement. Our day rate calculator started generating Google impressions within days. People search for calculators with very specific intent — they want an answer right now.
2. localStorage is underrated
Every tool stores data in the browser. No backend needed, no database costs, no GDPR headaches. Users can track expenses, manage clients, and forecast cash flow — all without creating an account. The data just stays on their device.
3. UK-specific beats generic
There are thousands of generic invoice generators. There are very few that know about UK statutory interest rates, HMRC expense categories, or Making Tax Digital requirements. Specificity wins.
4. Build for the pain, not the feature
The most popular tools aren't the most complex ones. The day rate calculator is simple — but it answers a question every new freelancer agonises over. The late payment interest calculator exists because people are angry about unpaid invoices and want to know their rights.
5. Cross-link everything
Every tool links to related blog posts. Every blog post links to relevant tools. The invoice generator links to the payment reminder generator. The tax calculator links to the expense tracker. This keeps people on the site and helps Google understand the content structure.
Tech Stack
- Hosting: Cloudflare Pages (free tier)
- Backend: None. Everything is static HTML + vanilla JS
- Storage: localStorage (per-tool)
- Export: CSV and PDF generation in-browser
- SEO: Schema.org markup, FAQ structured data, sitemap + IndexNow
- Cost so far: £0
What's Next
I'm building more tools based on what UK freelancers actually search for. If you're self-employed in the UK and there's a calculator or tool you wish existed, I'd genuinely love to hear about it.
All tools are free, no sign-up required: landolio.com/tools
Landolio is a free resource for UK freelancers and sole traders. We also publish guides on getting paid, chasing invoices, and staying HMRC-compliant.
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