Fair & Square

Fair & Square is a rental calculator application that takes into account rooms sizes and income, helping people split and pay their rent with ease. 

  • Client: Will Lundy

  • Role: Product Designer

  • Tools: Figma, Illustrator

  • Team: Engineer + Me


The Team

Will Lundy is an engineer I know who approached me about an app idea he had. Throughout this process we worked together to design an application that we knew would be something he could code in Xcode. Engineer and Designer speak is very different, and learning how to bridge that gap was educational for both of us. 

The Problem

Rental calculators are not comprehensive enough to cover multiple rooms, who uses them, and how much each tenant makes. Using more exact details will help each tenant feel they are paying their fair share. 

The Solution

Fair & Square helps calculate what everyone owes and helps keep track of rent payments. Income is a factor with the ability to change how much it factors in.

Extra rooms like private closets and bathrooms are taken into account. 

Competitive Analysis


Easy to split bills and rent with roommates. Can pay through the app. Can only pay equally or by %, doesn’t help split rent based on specific factors. They have a website feature outside of the app that loosely values the rooms based on things like windows, closets, bathrooms. 

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Fairly split rent and bills. Demo feature is nice, can see how it works clearly. They have a useful feature to rate the rooms perceived values on sliders and every roommate can rate it. Processing took a long time. No other values like room measurements or income are taken into account. 


A website to help split rent. This calculator is very simple. It’s smart how they give the total square footage and then each room, so it is a simple way to split the shared space equally. It also accounts for private bathrooms automatically assuming they are 100 sq feet. it doesn’t include income and makes the user calculate room sizes outside the website. 


How this affects Fair & Square

We want to emulate the ease and widely adopted nature of Splitwise but focus on fair rental splits and developing out from there. There is a place for us in the market to enter competitively as a detailed and customizable way to make every tenant feel like they are paying the fair amount.

User Interviews

"My roommate and I just guessed a number, but their room is so big and they have their own bathroom."

"I pay less because I've been living in my place much longer than the other roommates"

"My roommate makes double what I make, and their room is much bigger than mine, I'd like to factor in pay just a little bit."

"We use Venmo to pay rent."

"It would be nice to have a small rent reminder and show when a roommate has paid rent."

What I learned from talking to people

There are mulitple factors that go into a fair rent situation. Everyone must agree on the factors and be able to see the results and agree on those together. Room size, length of stay, income, and special features like privates closets or bathrooms matter to people. 


I was given this sketch by the engineer I am working with. We discussed what features were most important to set our app apart in the app store. I strongly felt having income be a factor would set our app apart as a rental calculator. There were already apps that helped pay rent and split bills. 


Wireframes + Flows

From here we pivoted features and kept many of the concepts laid out in this sketch. We took out "compare rent" and "find roommate". We reorganized the information architecture. 


Hifi screen designs

Next in my design process I started fleshing out a logo and screen designs. Here are are some of the screens I created but didn't make it through. I like to design a lot of very different screens and iterate, showing my designs to people and seeing which one they respond to best. I had to view the screens on both iphone and android, the colors can vary a lot from device to device. 


Clickable Prototype

This is my current MVP design for a rental calculator app with the ability to take income into account. 

This is not finished, this will be iterated but currently this is at an okay place to start showing around and testing. 

I am working with a programmer, who will start developing this version so we can start identifying where some of the UI/UX will needs to be altered.

I used Figma and Adobe Illustrator.