Growing a Body Measurement App to $3,000 in Monthly Revenue

Hello! What's your background, and what are you working on?

Hi! My name is Lewis, and I'm from the UK. I was first introduced to programming around the age of 10, when my dad brought home a BBC Micro Computer from the school he was teaching at. I've been coding one way or another since then.

I took up programming as a career and eventually worked for a consultancy where I did projects for companies like Barclays, Electrolux, Marks & Spencer, and BAE Systems (a huge military defence supplier in the UK).

My app Body Tracker (formerly "Progress") was designed to help people track weight loss, but it goes beyond the usual metrics of weight and BMI. Tracking weight in isolation can be really misleading, so the app allows users to see a much more rounded picture by giving them the tools to track body measurements, body fat percentage, and progress photos, as well as their weight.

The app makes $2k-4k per month, and on New Years Day 2018 I had my best day ever, taking over $1k in 24 hours — that's 4x the amount I took on the same day last year.

Body Tracker Website

What motivated you to get started with Body Tracker App?

I wanted to lose weight for my wedding in 2011, so my fiancée recommended The 4-Hour Body by Tim Ferriss. Apart from dietary advice, Tim suggests tracking weight, measurements, and photos. I didn't want to use a spreadsheet to log the data — it would take too long, plus I hate spreadsheets — but when I turned to the App Store to find an alternative, nothing fit the bill.

As I was already looking for an excuse to learn how to make iPhone apps, I decided to make it myself.

You have to solve a real problem and create unique value. I think this is where a lot of app developers go wrong.


I made it purely to fit my own purposes, and that first iteration was very, very basic, but I decided to put it in the App Store anyway. I was amazed to find that people paid for it. I've been working on it on and off ever since.

What went into building the initial product?

I was working a full-time job, and I knew I would be too tired after work to learn new skills, so I started getting up an hour early and working on learning iOS development before heading to the office. I found this to be a great way to start the day, and it was really enjoyable working on something totally for myself before going to work.

I bought a book on iOS development for about $30, and an Apple Developer account is about $100, but other than that I had no expenses. But you do need an Apple computer to make apps for iOS devices.

The app took around three months to build from idea to App Store. As someone who worked in software development I was very conscious of "scope creep" and wanted to make the ideal MVP. I also hacked things I couldn't figure out. For example, at that time there weren't many libraries for making charts in iOS, but there were a lot of libraries for the web. So I made a web page for the graphs and included it in the app instead of doing native graphs.

I had a couple of tools that really helped me along the way: The Head First series of books is an incredible resource for learning programming, but sadly they're no longer updating for iOS. I also used a bunch of tutorials from Ray Wenderlich, and they are still the main resource I would recommend to anyone looking to learn iOS development.

How have you attracted users and grown Body Tracker App?

Over time I have tried a lot of things to grow the app, but nothing has come close to making the app more visible in organic search in the App Store. For me, that has been the number one element in attracting users.

One of my other apps was featured in the US App Store, and it was getting one million impressions a day. The market is huge, but you need to be findable to take advantage.

It's no easy task though — the weight loss space is very competitive, and most of my competitors have much higher LTV than I do, so they can afford to spend a lot more on advertising. I am effectively priced out of the paid ads route. I haven't been able to generate ROI out of PR or sponsored articles either.

Body Tracker Features

My biggest success so far has been through focusing on ASO (App Store Optimisation). This has had a huge impact on how many people have been able to find the app, and it's really easy and quick to do, at least to start with.

I've also found that releasing regular updates, keeping crashes to a minimum, and encouraging users to leave reviews (and more recently, ratings) have all fed into my ASO efforts.

What's your business model, and how have you grown your revenue?

The app is monetised in two ways: In-App Purchases (IAP) to unlock more features, and adverts. The money returned from adverts is trivial, but I think the option to pay to remove them is a nice incentive to upgrade.

With my initial product I was charging up front and making less than $100 a month.

After giving it a more professional redesign for iOS 7, I made it free with IAP, and it started taking up to $500-1,000 per month.

You don't have to create all the value before you release it. Release early, and really listen to your feedback.


At the end of 2016 I started really focusing on ASO, and that allowed me to bring it up to $2-4k per month. I also improved the app's icon and sales pages, which I'm sure contributed too.

Now I like to do experiments, picking a particular conversion rate and trying something to increase it. I'm also increasing the A/B tests that I do.

What are your goals for the future?

After experiencing a $1k day, I'd really like to hit that every day.

One area I've been planting seeds for is to have a mailing list so I can sell related products to people who already trust the Body Tracker brand — selling healthy recipes, for example.

I'd also really like to get the app to the point where it is a subscription service. It will probably require adding calorie tracking, weight loss plans, or another feature that's valuable on an ongoing basis.

I also have a long wish list of features I want to add that I think will increase retention.

I'd love to replicate the success of Body Tracker with another app I have. I think it's underperforming at the moment, so it will be interesting to see if I can turn it around using a similar methodology.

Finally, I'd like to build a community of full-time app developers so we can help each other out with feedback and support as we grow our businesses.

What are the biggest challenges you've faced and obstacles you've overcome?

The toughest thing was to keep believing in the app for so many years when it was still an underperforming side hustle. I struggled for a long time with balancing the need to pay the bills and wanting to work on the app. But I kept making improvements when I could.

In 2016 I took a full time six-month contract with the intention of being able to take a few months off to work on the app once the contract came to an end. I then set myself a three-month deadline to make the app a full-time concern. It was only in the very last week that I was able to turn it around. Those kinds of deadlines are hard to impose on yourself and take seriously, but it made a big difference for me.

Have you found anything particularly helpful or advantageous?

I mentioned Ray Wenderlich already — you can get a lot of good info there. I'd also recommend the book Badass: Making Users Awesome, which gives you a totally new perspective on what your software (and all products) means to your customers. And for ASO, the App Masters Podcast has lots of good info.

I think it's also a really good idea to keep up with trends set by Apple. Get on board with new technology quickly — that way, you'll have a better chance of being featured by Apple, and you won't have to waste time playing catch-up with competitors who took the cues when they were given. With hindsight, it's easy to see how they signalled the bigger iPhone sizes coming from the UI tools they released in the years running up to it.

That said, one really important thing is to be super pragmatic. Developers have a tendency to want to make perfect code and refactor forever and ever. You have to ask yourself: "Will this make a difference for my customers?" If the answer is no, it's probably not worth your time.

And related to this, if you are going to make your own products and keep costs down you are probably going have to be a Jack of all trades. Study design, marketing, sales, customer communication, and statistics. Being an okay coder and okay at these things is better than being a world class coder and having no ability in other areas.

What's your advice for indie hackers who are just starting out?

You have to solve a real problem and create unique value. I think this is where a lot of app developers go wrong. It would be relatively easy to make yet another weight-tracking app — there are plenty of them in the App Store, and very few of them get a decent volume of downloads. It's the layers of extra features in Body Tracker that make it stand out from the rest and make it far more difficult to replicate.

That said, you don't have to create all the value before you release it. Release early, and really listen to your feedback. Do whatever you can to encourage feedback.

If you are going to make your own products and keep costs down you are probably going have to be a Jack of all trades.


Another thing that I've found useful: when considering new features to add, ask yourself if it's going to make it into your sales copy. If the new feature isn't going to encourage more people to download your app it probably isn't worth adding.

And for app developers, put effort into ASO. It might seem like a distraction, but if you want to make a living in the App Store, it's essential.

Where can we go to learn more?

My personal blog is Lewis Makes Apps, and I'm @lewisMakesApps on Twitter. I've recently found my way onto YouTube too. There aren't many full-time iOS indie devs out there, so please connect if you are in the same boat!

And if you have any questions about app development or indie life then hit me up in the comments!

Lewis Smith , Founder of Body Tracker App

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  1. 4

    One of—if not—my favourite stories so far on IH!

    As someone who's developing a workout builder (closely related category of app) it was great to hear your experience in building this... Especially liked learning it was an on-and-off thing you worked on for so many years, it's cool to hear this unorthodox, but seemingly viable way of building an app.
    Congratulations on all your success mate, I hope I can join you in that one day :)

    Would love to hear your more about your marketing, like other than ASO, how exactly did people know your product existed? Was it a slow trickle of users throughout the years just randomly stumbling across it in the Appstore?

    1. 3

      I have not had any success with marketing at all :(

      Weight loss is very competitive and the costs are higher than the profits I make. One of my long term goals is to make the app valuable enough that I can charge a subscription, that would make advertising more viable.

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      I see on Lewis' YouTube channel (linked in the article) he has some videos related to ASO and app marketing. Perhaps that can be of use to you?

      BTW, I like your presentation style in those videos Lewis

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        Thanks Jerrie :) YouTube is something I want to do more of, but I need to get faster at it.

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        Already checked them out, they were definitely informative.

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          Definitely experiment with ASO though. I used to hate it, but now I realise it's fairly quick to do, and when you do get good results it's a great feeling.

          Plus, all your competitors are doing it.

  2. 2

    Wow Lewis, those are quite good numbers. I never thought there would be anywhere near that amount of money to be made in a mobile app.

    Well done to you and Jenny for persisting with this for so long. I hope this inspires others as well!

    1. 1

      Thanks Jerrie, I never thought it would be possible either. Some luck I guess and being in a space where people are willing to spend money. There are certainly other people doing it though.

  3. 2

    Awesome story Lewis! Very inspiring for indie iOS developers, as many falsely believe it is not possible to make a living on the App Store as a on-man-shop. You are the proof that while it requires a lot of work, it is possible. Looking forward to get there!

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      I can assure you it is very doable. I know at least two people who have done it with niche apps, built from scratch after work. One of them made a real fortune and even after a few years it still makes ~$2.5k / month - a pretty nice long tail.
      I have grown my app to ~$3k / month in a few years and it's still organic searches only, haven't had time for marketing yet.

      Lewis's advice is spot on - build something useful and the word will spread. The market is incredibly huge, 1 billion users and 1.5b more if you create an Android version.

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        Amazing. Please fill out your IH profile with contact info, would love to get in touch!

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          I will eventually but I'm a bit hesitant at present :-) There are competitors out there and I still have some work ahead. There is one particular app that is a bit better in some aspects but has a terrible UI, bad name, and ASO and therefore sells much less from what I can tell. Any hints might help them, which is not what I'd need right now.

          My main learnings are:

          • Solve a real problem but ideally very difficult to implement => it will be difficult or impossible to copy. This creates a threshold to the market for others.
          • If you do it in your free time and it takes a lot of time to make it happen, small investors / businesses will have difficult time to compete with you - e.g. 2 years of my free time as a dev might be easily worth $100-200k, if someone wants hire a freelancer (not mentioning that they might fail and not deliver - see the previous point). If it's a niche and unsolved problem, it will be very risky for them to invest. This is another threshold to the market for others.
          • Listen to your unhappiest customers, they are the best source of feedback on what to focus on. Don't make excuses why it's not doable, just make it work.
          • If there is a big company as a competitor, under-do them - focus on the basics and do them better, forget the bells and whistles, and sell for much less than them.
    2. 2

      Thanks Kevin, it is not the gold rush it was once perceived to be, but there are people doing it. And Apple is helping more than ever.

      Find something people like and stick with it and keep experimenting :)

  4. 1

    Lewis, this is great! I think building mobile apps are a lot of fun, especially if they are also a successful business like yours! I am onboard with building a community of app developers on how we can help each other.

    1. 1

      Thanks, I'm glad you liked it :)

      There certainly is a lot of fun, although once it is your livelihood that adds a dimension of stress sometimes for sure! Same as any business :)

  5. 2

    This comment was deleted a year ago.

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      All of the devs I know who succeed on their own prioritise pragmatism over theoretical perfection. It's great advice :)