Gym Bag - The Gym Utility App

Welcome to my latest app, Gym Bag.

Gym bag is an all-in-one workout and nutrition utility app.

promo page image

You can see the official Gym Bag promotional page here.

It optimises and streamlines your workout and nutrition routine by:

  • Counting your sets
  • Timing your rests
  • Calculating which plates to use
  • Calculating macronutrient and creatine intake recommendations


  • Plate Calculator - Instantly calculates plates for any given weight, metric or imperial.
  • Set Rest Timer - Tracks sets and rest time between sets. Configurable to your routine.
  • One Rep Max Calculator - Calculates your one rep max.
  • Percent Of One Rep Max Calculator - Calculates the percentage of your one rep max to lift.
  • Macronutrients Calculator - Calculates daily protein, carbohydrate and fat target recommendations based on your fitness goals.
  • Creatine Intake Calculator - Calculates daily creatine recommendations based on phase; loading or maintenance.
  • Distance Calculator - Calculates the distance you will achieve by maintaining a specified pace.
  • Pace Calculator - Calculates the pace required to travel a certain distance in a specified time.

app image 1 app image 2 app image 3 app image 4 app image 5

Building the app


Why did I build this app?

My friend contacted me and suggested he needed something to help track his sets, time his rests and calculate his plates. I put together a super rough prototype in a couple of days - with no emphasis on UI, just something that worked.

To demonstrate how much of an MVP (well, not MVP - prototype :D ) this was, check the first screenshot I sent over below:

first prototype

Gradually, I added more features and expanded it to include things like basic nutrition calculators, as well as some basic cardio calculators. I tried to draw from my experiences too:

  • What have I needed before?
  • What will I need in the future?
  • What will add value?
  • How can I expand the audience of the app?

My plans are to keep expanding the features available - which I hope to be dictated by user-led demand.


This is a scary word, but kinda important. I need coffee to code and food to live - so it's important that I focus on this.

Once again I considered myself and how I treat apps. I'm a pretty frugal person, I will try to avoid even minimal financial risk if I am not sure about the value of the investment. I always ask myself:

How will this investment add value to my life?

Gone are the days when users will blindly buy apps, unless in rarer circumstances.

I want users to understand the value proposition of Gym Bag, without any commitment.

Thus I chose the following model:

  • Free app to purchase
  • Rest timer and plate calculator will need to be unlocked after they are used a certain amount of times
  • Additional themes can be purchased to change the look of the app

Using this approach, users can fully test and experience the app before purchasing, essentially going back to the days of game demos. If the user finds value in the app, they will be more likely to pay a little more for it than the standard lowest tier 1 entry price on iTunes.

I think this makes app pricing much fairer to everyone involved - and it avoids the messiness and ugliness of ad-supported free versions. Ads suck.


To aid launching I created an official Gym Bag promotional page here.

I also created a social promotion on the Facebook page of the app, for users to stand a chance of winning 1 in 10 free full app bundles - for liking the page and sharing the post. Pretty standard.

At this current date (25/03/2016) the app is pending review in the app store. Once it goes live, it will be available here..

The Facebook page is here too.

Please feel free to check out the app, it's free anyway! And if you know anyone else that might like it, please share with them too!

As ever, hit me up on Twitter @philhudson91 if you have any questions or suggestions.

Bye bye from Vietnam!

Phil Hudson

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