QuickToKnow is a collection of free calculators and plain-English explainers for the moments when a number actually matters — what a salary is worth after tax, how much a bank will lend against an income, what a currency is really worth before anyone adds a margin, what today’s expense will cost after ten years of inflation.
There are ten calculators on the site today, grouped around money, health, property, education and travel: a currency converter running on live mid-market rates across 160 currencies; take-home pay for the United States, Canada and the UAE; VAT for the UK and the EU; an inflation projection that compares four major economies; a financial health check; mortgage affordability; BMI; daily calorie needs; GPA; and a time zone converter. Alongside them sit longer guides — one on the world’s most exclusive credit cards, one on the Moon’s phases through the year.
Built for more than one country
Most calculators on the web quietly assume you are American. These do not. Take-home pay switches between US federal and state withholding, Canadian federal and provincial tax with CPP and EI, and the UAE, where salaries carry no income tax at all but GCC nationals contribute to the GPSSA. Mortgage affordability applies the lending guidelines actually used in the US, the UK and Canada rather than one blended rule of thumb. The financial health check rewrites its own questions for India, the US, the UK, the UAE and Singapore — because “how is your health insurance covered?” means something quite different in each of them.
Where the numbers come from
Every financial and health tool names its sources on the page itself, rather than burying them in a policy document. US payroll figures come from IRS Publication 15-T and Publication 15 (Circular E), with the Social Security wage base from the SSA. Canadian brackets, CPP and EI rates come from the Canada Revenue Agency. UAE pension contributions come from the GPSSA. BMI categories follow the World Health Organization’s classification. Calorie estimates use the Mifflin-St Jeor equation. Mortgage rules cite Fannie Mae, Freddie Mac and the CFPB in the US, the FCA’s MCOB rules in the UK, and CMHC in Canada. Passport rankings come from the Henley Passport Index.
Exchange rates are pulled live from a public mid-market feed. When that feed cannot be reached, the page says so plainly and shows the date of the stored rates it fell back to — a tool that quietly shows stale numbers as live ones is worse than one that admits it.
What these tools are, and what they are not
They are estimation tools built for planning and understanding, not financial, medical or legal advice — and every one of them says so on its own page, not only in the site disclaimer. A calculator cannot know your benefit elections, your local city taxes, your medical history or how a particular lender underwrites. Treat the output as a well-sourced starting point for a conversation with a professional, not as a substitute for one.
Using the site
Nothing here asks you to create an account, hand over an email address, or pay. The calculators run in your browser, and they do not store what you type into them.
Found a figure that looks wrong, or a country whose rules have changed? Tell me — corrections get made, and every tool page carries the date it was last updated so you can see how current it is.