About ConvertNow
I am Prateek, an independent developer in Berlin. ConvertNow is the tool site I wanted to exist and could not find, so I built it one utility at a time.
No company behind it, no funding round, no growth team. Just the tools I kept needing, made free for everyone else who keeps needing them too.
The tab that started it
It was a Tuesday night and I had one job left before logging off: make an ugly API response readable so I could find the field that was breaking a build. Four seconds of work.
The first result asked me to sign in with Google. The second showed a cookie wall, then an ad that covered the input box on mobile. The third worked, but only for the first 500 lines, and told me to upgrade for the rest. By the time I found something usable, twenty minutes had gone and I was angrier than the bug deserved.
I have had that exact evening more times than I can count. A quick unit conversion, a percentage, a timestamp, an image that has to drop under five megabytes for some portal. Small jobs, all of them, sitting behind a signup form or a paywall or a page so cluttered that the tool itself was below the fold.
What I actually do
By trade I am a software developer, currently in Berlin, with roughly 8+ years of building things that have to work in production rather than in a demo. Most of that time has been spent in Software & ML Solutions, API Building, Dashboarding, etc which is exactly why the developer and data categories on this site are the deepest ones.
ConvertNow is not my job. It is the thing I open in the evenings and at weekends, usually because I hit a problem during the day and thought, that should have taken ten seconds. That is a slower way to build a site with 150 tools on it, but it does mean every single one exists because somebody actually needed it, starting with me.
How a tool gets made
The process is unglamorous and it is the same every time.
- It starts as an annoyance. Either mine, or an email from someone who could not find a tool that does the specific thing they needed.
- I read the actual specification. Not a blog post about it. If it is Base64, that means RFC 4648. If it is a BMR calculation, that means the Mifflin St Jeor paper. If it is contrast, that means the WCAG definition of relative luminance.
- I try to break it before you can. Empty input, enormous input, emoji, leap years, negative numbers, daylight saving boundaries, malformed syntax. A tool that only handles tidy input is not finished.
- It runs in your browser if it possibly can. Sending your data to a server is a last resort, not a default.
- The page says how it works. Which formula, which standard, and where the answer should not be trusted blindly. A number with no stated assumptions is worth very little.
Then it ships, usually the same weekend, and I move on to the next annoyance.
What it costs and how it is paid for
Hosting, domains, a few third party services and a fair amount of my own time. That is covered by a small amount of advertising through Google AdSense and an optional coffee button. Nothing else.
There is no premium tier and there never will be. No tool gets locked, no result gets watermarked, no export gets capped. Ads exist so the tools can stay free, which is the whole point. If I ever cannot make that work, I would rather say so plainly than quietly start charging for the thing you came here for.
Things I refuse to do
I will not put a tool behind an email form. I will not store what you paste in, or use it to train anything. I will not add a popup that covers the input on mobile. And I will not publish a calculator without saying what it assumes, because that is how people end up trusting a number that was never built to carry that weight.
Analytics on this site are aggregate only, through Google Analytics and Jetpack, and that is spelled out in the privacy policy rather than buried in it.
Where the roadmap comes from
Almost entirely from email. Someone writes in describing a job they do by hand every week, and if it is a fair fit for a browser tool, it usually exists a fortnight later. Bug reports go to the same inbox and land with the person who wrote the code, not a ticket queue.
If there is something you keep wishing existed, tell me about it. That is genuinely how most of this site got built.
Six things I hold myself to
These are not marketing lines. They are the constraints I check a tool against before it goes live, and the reasons people come back rather than searching again next time.
No sign up, ever
You will never hit an account wall to use a tool here. Open the page, get your answer, close the tab. There is no email capture, because there is nothing I want to send you.
It runs on your machine
Around 130 of the tools process everything locally in JavaScript. Your JSON, your salary figure, your photo, none of it is uploaded just to compute a result.
Built off the actual spec
Converters follow the published standard and calculators follow the named formula, and each tool page says which one. No guessing, no rounded constants copied from a forum.
One tool, one job
Every tool exists because a real task needed it, mine or someone else’s. Nothing is here to pad a category or catch a keyword.
Honest about tracking
Aggregate analytics through Google Analytics and Jetpack, ads through AdSense, and that is the full list. It is stated plainly in the privacy policy rather than hidden in it.
Your email reaches me
Bug reports and requests go straight to the person who wrote the code. No support queue, no ticket number, no bot asking you to rate the interaction.
The same engineering, pointed at your problem
Everything on this site is something we built to solve a real problem quickly and properly. We do that as consulting work too. If your team has a job that a spreadsheet has outgrown, or a process that runs on somebody manually copying data between two systems, that is the kind of thing we are good at.
Small, focused engagements rather than year long programmes. Usually a scoped build with a clear finish line, handed over with documentation so you are not tied to us afterwards.
Custom internal tools
The calculator, converter or dashboard your team keeps rebuilding in a spreadsheet. Built once, properly, with your rules and your edge cases baked in.
APIs and integrations
Designing, building and documenting APIs, or wiring two systems together that were never meant to talk. Including the unglamorous parts: auth, rate limits, retries and error handling.
Web platforms
Full builds from the database up, or rescuing something that already exists and has become slow, fragile or impossible to change safely.
Data and machine learning
Turning messy data into something you can actually decide with. Cleaning and modelling, forecasting, classification, and getting a model into production instead of leaving it in a notebook.
Where we tend to be a good fit
- You know the outcome you need but not the shape of the solution
- A repetitive manual process is quietly eating hours every week
- You have data and a hunch, and want to know whether the hunch holds
- You want one senior person who ships, not a team you have to manage
Where we are honestly not
- Large multi team programmes that need a full agency behind them
- Anything that needs an answer today, since good scoping takes a week
- Projects where the brief is add AI to it with no problem attached
- Ongoing staff augmentation billed by the seat
Tell us what is slowing you down
A paragraph is enough to start. Describe the problem, roughly what success looks like and any deadline you are working to, and you will get an honest answer on whether it is a fit, including if the answer is no.
The questions people email me
Who runs this, how it pays for itself, and what happens to the things you paste in.
One person. I am Prateek Zare, an independent software developer based in Berlin, and I design, build and maintain every tool on the site myself. You can find me on LinkedIn or email me directly at [email protected].
No. It is an independent project, not a funded startup and not a product owned by a larger business. There is no team, no investor and no roadmap decided in a meeting. That is also why the tools stay simple: there is nobody here whose job depends on adding features you did not ask for.
Hosting, domains and third party services cost real money, and that is covered by a small amount of advertising through Google AdSense plus an optional coffee button. Nothing else.
Yes, it stays free. There is no premium tier planned, no tool will be locked, no result watermarked and no export capped. Ads exist so the tools can stay open to everyone, which is the entire point of the project.
No. For most tools the question does not even arise, because the processing happens in your browser and the input never reaches a server at all. That covers every formatter, converter and calculator on the site.
A smaller group has to contact a server, since a browser cannot run those checks alone. DNS lookups, WHOIS, ping, port checks, SSL certificate checks, page speed and some heavy file conversions all work that way. In those cases only the domain, IP or file you submit is sent, it is used for that one request, and it is not kept. The details are in the privacy policy.
Because each tool tells you what it is doing. Converters follow the published standard, such as RFC 4648 for Base64 or RFC 4180 for CSV, and calculators follow the named public formula, such as Mifflin St Jeor for BMR or the WCAG relative luminance definition for contrast. Unit conversions use exact SI factors rather than rounded ones.
Where a result depends on assumptions, the page states them. Health tools are general estimates and not medical advice, and finance tools are arithmetic rather than financial advice. If something ever looks wrong, send me the input and I will reproduce it.
Please do. Most of the site exists because somebody asked. Email [email protected] and describe what the tool should take as input and what it should give back. If it is a fair fit for a browser tool it usually appears within a couple of weeks, and requests that arrive more than once move to the front.
Yes. Alongside the free tools we take on a small number of consulting projects: custom internal tools, APIs and integrations, full web platforms, and data and machine learning work. Engagements are scoped with a clear finish line and handed over with documentation, so you are not tied to us afterwards.
Describe the problem in an email to [email protected] and you will get an honest answer on whether it is a fit, including if the answer is no.
Yes, and plenty of people do. Anything a tool produces from your input is yours, including QR codes, barcodes, generated passwords, converted files and generated markup. There is no attribution requirement and no watermark. The generated privacy policy and cookie consent text are starting points rather than legal advice, so have a professional review them before publishing.
Go and use something
That is what the site is for. Browse the full library, or write to me if there is a tool you keep wishing existed, or a problem at work that needs building properly.
No sign up. No paywall. Just tools that work.
