About TaxRationale
TaxRationale was built on a simple idea: personal tax software should explain its reasoning, not just produce a number. We combine accurate calculations with plain-language explanations so that South African individuals and tax practitioners can prepare, compare scenarios, and file at SARS with confidence.
Show the reasoning
A tax number you can’t explain is a tax number you can’t defend. Every computation in TaxRationale shows which schedules applied, how each figure was reached, and what the effective rate is, from basic income tax to capital gains and cross-border scenarios. The result is something a practitioner can defend and a client can understand, and it exports to a plain-language report you can keep or attach when you file.
Private by design
Tax data is sensitive, so the engine runs entirely on your device and works offline. Your data is encrypted; we can’t read it from our servers. The keys are derived from your password on your device, and what reaches us is ciphertext. The full mechanism is described in plain language on the Security page.
Checked against SARS tables
Every rate, rebate and threshold in the engine is checked against the published SARS tax tables for each supported year of assessment, and an automated accuracy suite guards the math on every change. The engine, every schedule and the reports are free, because stale or paywalled tax math is a trust hazard; encrypted sync across devices is the paid feature.
Who is behind it
TaxRationale is built and run by Thomas Lobban, a SARS-registered tax practitioner (LLB, LLM in Tax Law, and a Master Tax Practitioner (SA) with the South African Institute of Taxation). It is a division of Ibex Consulting (Pty) Ltd (registration 2017/283495/07), a South African company. Questions are welcome at hello@taxrationale.com.