Who builds EstimateBill

A one-person software business, and an app with no server behind it. Here is who makes it, why it works the way it does, and how the tax information is put together.

The person

Gurjeet Singh builds and maintains EstimateBill under Sharpen Solutions. I write the app, the tax registry, this website and the guides on it. There is no content team — if something here is wrong, it is my mistake and I would like to know about it: support@estimatebill.com.

I build offline-first software for small businesses. That is a narrow specialism and a deliberate one: most tools for sole traders are cut-down versions of products designed for companies with finance departments, and they carry the assumptions that come with that — an account, a server, a subscription, a sync you have to trust.

Why the app has no account

Every invoice app I looked at wanted an email address before it would let me type a line item. Then a verification link. Then a plan. Then it held the whole customer list on a server I had never seen, under terms that change when a company is acquired.

None of that is needed to produce a correct invoice. A phone from 2019 can store a few thousand invoices and render a PDF without help. So EstimateBill does exactly that: the database is on the device, the PDF is rendered on the device, and there is no server to hold anything. The honest cost of that decision is that backup is a manual step — the full trade-off is set out here, including the cases where a cloud product is the better tool.

How the tax data is put together

The app ships a registry of 58 countries: for each one, the tax's local name, the rates in use, the label for the registration number, and the format customers expect. That is the part of this work with the highest chance of being wrong, so it is worth saying plainly how it is maintained.

• Rates and registration thresholds are taken from each country's own tax authority, not from aggregator sites.
• Everything currently in the app and on this site was checked to mid-2026. That date is printed on every country page.
• Where a country has no single national rate, the app leaves it blank and asks you to enter yours. The United States is the clearest case — the rate depends on state, county and sometimes city — and inventing a default would be wrong nearly everywhere it was used. Brazil is left open for related reasons.
• Rates change, and some of these will be out of date before I notice. Your own tax authority is the only current source, and nothing here is tax advice.

If you find a rate or a rule that is wrong for your country, emailing me is genuinely the fastest way to get it fixed.

What I will not do

• No advertising. Not a banner, not an interstitial, not a watch-an-ad-to-unlock. An app holding your client list is the wrong place for an ad network's SDK.
• No analytics SDK. I do not measure how you use the app, because doing so would require sending something off the device.
• No invented reviews or ratings. When the app has real ratings they will appear here. Until then there are none, which is why you will not find a star rating anywhere on this site.
• No fake urgency. No countdown timers, no "3 people are viewing this".

The rest of the site

The same reasoning produced the browser invoice generator, which uploads nothing and stores nothing, and the guides library, which is free and asks for no email address. If a tool can work without collecting anything, it should.

Contact

Bugs, feature requests, corrections and awkward questions all go to the same place: support@estimatebill.com. The support page covers the common ones.