I automated my entire freelance admin with free tools I built myself

I got tired of paying for five different SaaS tools to run my freelance business. So I built my own — and made them all free. Here's the stack I use now, all browser-based, no sign-up, no subscription: Invoicing Invoice Generator — Fill in details, preview, download PDF. That's it. No account needed, no watermarks. Takes about 90 seconds. Payment Reminder Generator — When clients don't pay (and they won't), this generates the right email for the right stage. Friendly nudge → firm reminder → final demand. Copy, paste, send. Late Payment Interest Calculator — Under UK law, you can charge 8% + base rate on late commercial invoices. Most freelancers don't know this. This calculator tells you exactly how much. Tax Self-Employed Tax Calculator — Income tax, NI, student loan, take-home. Instant breakdown for 2025/26. Day Rate Calculator — Back-calculates your day rate from target salary, accounting for tax, expenses, sick days, and holidays. Most freelancers undercharge because they don't do