About Zhaku

Why Zhaku exists

Somewhere between "just Google it" and "download our app" there's a gap: simple money questions that deserve a fast, honest answer without pop-ups, cookie walls or an email signup form standing in the way. Zhaku fills that gap. Eleven calculators, no accounts, and no adverts chasing you down the page.

The name is short, made up, and easy to type on a phone - which is roughly our design philosophy for the whole site.

How the calculators are built

• Everything runs in your browser. When you type a mortgage balance or an invoice amount, that number never leaves your device. Our server sends you the page; the arithmetic happens locally.
• Standard, published formulas. Mortgage and loan payments use the textbook amortisation formula; VAT follows HMRC's net-based method; the overpayment tool runs a month-by-month simulation. Each page explains its method in plain English.
• Workings shown. Wherever practical, the sum is written out under the result so you can check us - or repeat it yourself later.

What we don't do

We're not advisers, brokers or lenders, and nothing here is financial advice. Calculators like ours are ready-reckoners: brilliant for comparing options and building intuition, no substitute for a formal quote, a mortgage illustration, or a conversation with a qualified professional when the stakes are high.

We also don't profile you. There's a single anonymous counter that tallies how many times each calculator is used per day - that's the entire analytics stack. The details are in our privacy policy, which is mercifully short.

Keeping the numbers current

Rates and thresholds mentioned in the written content - VAT rates, the registration threshold, typical lending multiples and tax bands - are reviewed against official sources such as GOV.UK and the Bank of England periodically, and corrections are usually shipped quickly. Each calculator explains its assumptions on the page, including the tax year or rate basis used.

Our editorial standard

Zhaku's explanations are written for this site, not copied from another calculator. We separate a mathematical estimate from financial advice, link readers to primary or impartial sources, and avoid making promises about approval, savings or returns. When a rule can change, we show the date or tax year and tell you where to verify it. If you spot an error, the best route is to use the official source linked on the relevant page and treat the result as a sense-check while we correct the copy.

We do not sell mortgages, loans, tax services or financial products. The site is funded by advertising, but advertising does not determine the formulas, editorial explanations or links we publish.