Ashar Pervaiz
Who I Am
I am a software engineer from Karachi, Pakistan, with a degree in Software Engineering from the University of Karachi (UBIT), where I studied from 2021 to 2024. I work as a web developer at Social Gravity and have been building for the web for over two years, mostly in React, Next.js and WordPress.
Numbers On Your Tip is mine. I designed it, wrote the code for all 62 calculators and tools, and wrote the twenty-nine guides that sit alongside them. There is no content team and no ghostwriter — if something on this site is wrong, it is my mistake.
What I Am Qualified to Say, and What I Am Not
This is the part most author pages skip, and it is the part that actually matters when you are deciding whether to trust a number.
My expertise is engineering: implementing a published formula correctly, handling the edge cases, and building an interface that does not mislead. I am not a doctor, a pharmacist, an accountant or a financial adviser, and this site never claims otherwise.
That is why the clinical calculators and health guides are reviewed by someone who is qualified. Dr. Syeda Khadija Akbar, PharmD reviewed the dosing logic, unit handling and safety wording on every medical page. Her review covers clinical content only — it does not extend to the finance or maths tools, and those pages do not claim it does.
How I Build a Calculator
Every tool starts from the source that professionals in that field actually use — WHO standards for BMI, the U.S. Navy method for body fat, Mifflin-St Jeor for calorie needs, the standard reducing-balance formula for loans, published IRS and HMRC rates for tax.
Before a calculator goes live I test it against worked examples where the correct answer is already published, so I am checking the output against a known result rather than against my own arithmetic. Each page then shows the formula and a worked example in plain text, so you can verify the maths yourself instead of trusting a black box.
Where a figure changes over time — a tax bracket, a clinical cut-off — the page states the year it applies to and gets updated when the underlying number moves. Review dates are recorded on the about page.
Why I Built This Site
Most free calculator sites answer the question and stop. You get a number with no formula, no worked example, and nothing about when the method stops being reliable — which is exactly when you most need to know.
I wanted the opposite: the answer, the working, and an honest statement of the limits. That is why the guides spend more time on where a calculation goes wrong than on the arithmetic itself, and why every calculation runs in your browser rather than on a server. Your figures are never transmitted or stored, which is a design decision rather than a marketing line.
Technical Background
| Area | Tools and technologies |
|---|---|
| Frontend | React, Next.js, JavaScript, HTML5, CSS3, Tailwind CSS |
| Backend and data | Node.js, PHP, MySQL, Supabase |
| CMS and platforms | WordPress, Shopify, Webflow |
| Design | Figma, Adobe XD, Photoshop, UI/UX design |
Numbers On Your Tip runs on Next.js and React as a fully static export, which is why pages load quickly and why no calculation needs a server round trip. Other work of mine — PHP applications, WordPress themes and Shopify storefronts — is on my portfolio.
Corrections
If you find a wrong result, a broken edge case or an out-of-date rate, tell me and I will fix it. Corrections to a live calculator go out the same week, and the page's review date is updated when they do. The fastest route is the contact page.
Articles by Ashar Pervaiz
Twenty-nine guides, newest first. Each one is written to be read alongside the calculator it relates to.