About Calculator

Calculator is a working reference for the money questions people in Tanzania actually have: what reaches your bank account after PAYE, NSSF or PSSSF and an HESLB deduction; what an employer pays on top of a wage; what it costs to send or withdraw mobile money at each network; what 18% VAT does to a price; what a loan, a mortgage or a plot of land really costs once the fees are counted.

It is built and published by Delta Tech Solutions in Dar es Salaam, Tanzania. It is independent: not affiliated with the Tanzania Revenue Authority, NSSF, PSSSF, HESLB, WCF, EWURA, TANESCO or any bank, telecom, lender or bureau de change whose rates appear in the calculators. Nobody pays to appear in a result, and no provider has any influence over what a calculator says.

Alongside the Tanzanian tools there are everyday utilities — percentages, BMI, loans, unit and currency conversion — kept because people arrive looking for them. They are supporting tools, not the reason the site exists.

Who is accountable for the figures

The site’s figures are maintained by David M at Delta Tech Solutions. Every tool, guide and category page is stamped with the date its figures were last checked and the date the next check is due — 6 months later — so a page that has gone unchecked is visible as such rather than quietly ageing. Where a page publishes a rate that has not been checked against a readable source yet, the line says that instead of printing a date: five payroll and mobile-money figures are in that state today (NSSF, PSSSF, SDL, HESLB and the withdrawal levy), and the register shows them alongside the figures that are dated. The most recent hand revision of the site’s reference text is 12 October 2026.

No page here has been reviewed by an external qualified professional. Nobody with a tax, accounting, legal or medical qualification has checked these calculations or this wording, and we do not claim otherwise. The calculators apply published rules to the numbers you type in; they are not advice, and they cannot see your circumstances.

How we ensure accuracy

Because people rely on these tools for payroll and regulatory calculations, accuracy is engineered in rather than assumed. Every control below is live on this site:

One dated register for every figure. Rates and rules (PAYE bands, VAT, NSSF and PSSSF contribution rates, WCF, mobile-money tariffs, electricity rates, exchange-rate sourcing) live in a single verification register with the authority behind each one, the method used to check it, and the date it was last checked. The sources and methodology page publishes the whole register.
A weekly re-check of the sources. Figures an authority publishes in a form we can read automatically — the PAYE bands, the standard VAT rate, the WCF rate, published electricity rates — are re-read every week. An unchanged figure’s date moves forward; a changed one is published only if it passes structural and size checks, and is otherwise held for a person to look at. Figures no machine can read keep the date a person last checked them and appear on a monthly review list. No date on this site is written by a clock.
Known-value tests. Every money, tax and conversion engine is checked against hand-computed results for fixed inputs, so a change can never silently shift an answer.
Boundary-condition tests. Tax bands and fee tiers are tested exactly at their edges — salaries and transfer amounts that fall right on a band limit — where off-by-one errors are most likely.
Shared calculation engines. The calculator, its comparison view and its worked examples all call the same engine functions, so there is no second copy of a formula to drift out of sync.
Programmatically generated examples. Worked examples and guide figures are generated from those same engines, so when a rate changes the published example updates with it, and a test verifies the two can never disagree.
Every page says what it cannot do. Tools state the assumptions they make and the situations where the answer does not apply, and financial and health pages say plainly that no external professional reviewed them.

Corrections and updates

If a figure is wrong, that matters more than anything else on this page. Email calculatorcotz@proton.me with the page, the figure, what you believe it should be, and the source you are checking against — a TRA notice, an operator tariff sheet, an EWURA order, whatever the number actually comes from. A correction is applied once in the shared engine, every dependent example and page is regenerated, and the full test suite has to pass before the fix is published.

Material corrections are listed publicly in the corrections log, alongside the sources, the review cadence for each figure, and how to report an error.

Using the site

Everything is free, with no account and no sign-up. Any calculator can be embedded on another site — see “Embed this calculator” on each tool — and calculators that follow Tanzanian rules can be switched to show results in shillings. Journalists can find logo files, a ready description and a fact sheet on the press page, and questions, corrections or ideas for new calculators are welcome by email.