James Hartley

James Hartley is a Chartered Management Accountant (CIMA) with more than eight years of experience in UK tax, payroll and compliance. He holds a BSc in Finance and Economics from the University of Manchester and spent his early career at a Big 4 accounting firm. He founded WhatsUK to build free UK financial calculators and guides verified against official HMRC sources.

James founded WhatsUK because he recognised a significant gap in the market: most free UK financial calculators online were either inaccurate, out of date, or so poorly explained that users could not understand the results. As someone who spent years working with HMRC tax legislation every day, he was well placed to fix this. WhatsUK launched with a small set of salary and tax tools, and has grown to cover more than 40 calculators across salary, tax, property, business, and personal finance.

James personally builds every calculator on WhatsUK, writes the methodology behind each tool, and verifies all rates against official HMRC publications before each tax year begins on 6 April. He specialises in making complex UK tax rules - personal allowance tapering, corporation tax marginal relief, IR35 status assessment, CIS deduction rates, and stamp duty first-time buyer relief - accessible to everyday people without a background in accountancy.

He also authors all articles on the WhatsUK blog, translating changes to UK tax rates and legislation into plain-English guides that anyone can follow. All articles are fact-checked against official HMRC sources before publication.