Public Statum product - Case study
Kenya salary calculator: showing where the money goes
A take-home figure is easier to check when you can see the deductions behind it. We built a salary calculator that keeps the selected period, PAYE calculation, and net salary together.
By Statum Company Ltd - Published
Try the salary calculator ->The problem behind a single number
Someone comparing a job offer needs to understand how gross pay becomes take-home pay. An employer checking a payroll figure needs to see which period and deductions were used. A result with no explanation makes both tasks harder.
Our public calculator starts with gross salary and a statutory period. It also accepts pension contributions, mortgage interest, insurance premiums, post-retirement medical fund contributions, and residency status. These are separate inputs because changing one assumption can change the result.
What we built
- A breakdown of NSSF, SHIF, Housing Levy, PAYE, total deductions, and net salary.
- PAYE band calculations and reliefs shown separately from the final tax amount.
- A period selector so the calculation uses the relevant configured contribution schedule.
- A downloadable salary breakdown using the same calculation service as the result endpoint.
One service for API results and exports
The PHP calculation service produces a structured result containing gross pay, taxable income, individual deductions, reliefs, and net pay. The result also carries the selected period and a PAYE band breakdown. That gives the interface more to work with than a single total.
The JSON response and PDF export call that same service. This reduces the number of places that need to change when a calculation rule is updated. Monetary results use an explicit rounding rule, and the request validates the inputs before calculating.
The selected period matters. NSSF contribution settings are resolved from that period instead of applying one schedule to every calculation. Tax and contribution settings live in configuration, making the assumptions easier to inspect and review.
What a reader can check
The calculator is public. A reader can choose a period, enter a gross salary, change an optional input, and compare the displayed components. The PDF gives them a copy of the calculation to discuss with a payroll team.
This case study describes the software we built. A calculator estimate does not establish an employee's full tax position or replace a payroll review. The applicable rules, supporting documents, and individual circumstances still need to be checked.
KRA explains the employer's PAYE responsibilities in its PAYE guidance. Its notice on deductions, reliefs, and exemptions provides further context. These are reference sources, not an endorsement of Statum.
Applying the same approach to business software
A financial workflow needs a clear record of its inputs and assumptions. The same questions come up in billing, commissions, loan schedules, and reconciliation: which rule was used, what changed, and can someone explain the total?
Our ERP and workflow automation service covers the wider records, approvals, and reporting around those calculations. The vehicle import duty calculator case study shows how we handled another rules-based product.