Mon–Fri 08:00–17:00
Rooka Systems RookaSystems

Free tools

IT tools

Small calculators we use ourselves. Everything runs in your browser — nothing you type here is sent anywhere, including to us.

Subnet calculator

What a CIDR block actually gives you: the range, the broadcast address and how many devices fit.

Backup window

How long a backup takes over a given link — the number that decides whether an overnight backup actually finishes overnight.

GB
Mbps

How long would that password last?

A rough time-to-crack for an offline attack. It is an order of magnitude, not a promise — but the difference between “minutes” and “centuries” is the point.

Nothing is sent anywhere — but type something like your password rather than the real one. That is good practice on any site, including this one.

Monthly filing calendar

The recurring Tanzanian deadlines, by day of the month.

DayWhatWho
7 PAYE and SDL
Employment taxes for the previous month.
TRA
15 NSSF contributions
Employee and employer pension contributions for the previous month.
NSSF
20 VAT return
For VAT-registered businesses only. Due even in a month with no sales.
TRA
30 WCF contributions
Monthly, against the payroll.
Workers Compensation Fund

Deadlines only — no rates or thresholds, because those change and a stale number here would cost somebody money. Confirm the amounts with TRA or your accountant. Annual filings (BRELA returns, licence renewals) sit outside this monthly cycle.

Why there is no “send me the results” button

A subnet plan and a backup window are facts about your network. We would advise a client against typing those into somebody else's website, so this page has nowhere to send them — no form action, no analytics on the inputs, nothing. Everything above is computed by your own browser.