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WorthSpan Case Study: Salary and Tax Calculators You Can Check Line by Line

Screenshot of getworthspan.com (opens in a new tab), taken 2026-11-04.
WorthSpan tells people what their income is really worth: take-home pay after tax and statutory deductions, what a raise is worth, and what a salary buys after inflation. We built and run it.
At a glance
- Owner: Kavenacc (our own product)
- Sector: Personal finance web app
- Location: 89 countries, Kenya first
- Live site: getworthspan.com (opens in a new tab)
The goal
Give accurate take-home pay figures that anyone can check, with no login and no black box.
What we built
- A salary-after-tax calculator with verified 2026 payroll rules for 89 countries and US states
- Pay raise, salary-to-hourly and inflation-adjusted salary calculators
- Net-to-gross calculation and a payslip PDF
- Every result shows the exact formula and each step
- Tax rules versioned by tax year and dated when verified, from named government and statistical agencies
- Calculations run in the browser, figures stay on the device, and no signup is needed
Numbers you can check
Salary tools usually ask you to trust a number. WorthSpan shows the working, so a payroll officer, an employee or an HR team can check it line by line.
This is one of our own products, built and run by the same team that builds client sites.
Lessons for similar businesses
- Show your working; it builds more trust than a nice design.
- Date and version any rules that change every year.
- Keep personal figures on the user's device.
More work
See all case studies, or read our guides to website costs in Kenya and choosing a web design company in Nairobi.
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