Simplifying bill-splitting with friends
iOS Mobile App  •  Usability Case Study


What are Splitwise’s current iOS mobile app usability issues? How might Splitwise reduce friction in the bill-adding process?


As a product designer (not affiliated with Splitwise), I took on this personal project to explore applying the human-centered design process to improve the usability of Splitwise.


Research, Information Architecture, Ideation, Interaction, Visual Design, and Prototyping & Testing.

Project Outcomes

Working within Splitwise’s current design guidelines, I implemented changes to reduce friction in the app.




I interviewed 6 people to identify existing pain points, jobs to be done, and how they are currently being solved for.

By using job stories, I was able to better understand why and how people would use Splitwise and ensure that I was helping to solve a core problem that the app attempts to solve.

Usability Testing

To discover pain-points in the user experience of the Splitwise iOS mobile app, I started my research by conducting guerrilla usability tests at coffee shops around the San Francisco and San Jose area. I made a few assumptions as to who the common user of the app would be and set out to find people who:

1. Were approximately in their 20s-30s
2. Shared expenses with others at least once every few weeks.

User Tasks

I talked to 7 participants and had them use Splitwise to complete a few tasks similar to the following:
You’ve paid for a meal ($25) that you split with 2 other friends. One of your friends decided to order an extra drink ($3) for him/herself. Find out how much each person owes you.


Synthesis & Analysis

After reviewing notes & video recordings of my test subjects, I documented key questions, hesitations, frustrations, and points of confusion they encountered on post-it notes. I used a different color post-it note for each participant and then grouped pain points into key themes.


In order to prioritize the key pain points to focus on, I proceeded to map out the pain points on a 2×2 grid.  I considered factors such as the level of importance to the user, ease of implementation, and the level of importance to the business to help identify quick wins for the business that would have the most impact.

This process allowed me to identify the scope of work for improvements I wanted to make and cut out work that did not directly impact a high priority user need.

pain points & takeaways

Based on this exercise, I was able to identify the following key pain points and takeaways to focus on:

Key Takeaway:

Speed and accuracy are key for the adoption of Splitwise. If a user felt a particular feature took too long to understand, they would just give up on using the app.

“At this point, if I couldn’t figure it out, I would just do the calculations myself.” 

Task Flow Analysis

After identifying and prioritizing key pain points, I mapped out a task flow to help identify the key areas my changes would impact (denoted in red).



For each part pain point in the task flow, I made an effort to think broadly by exploring at least 3 potential solutions for each paint point, and then slowly narrowed down my options to a solution that would be relatively easy to implement, but have a high impact for the users. I made it a goal to bring in additional perspectives as I mixed and remixed design ideas.


Once I synthesized the various ideas into a specific design, I transformed the sketches into wireframes.


I leveraged my wireframes to get feedback on the feasibility and impact of my ideas. After iterating on the design and changes to the flow, I worked in Sketch and Marvel to create an interactive prototype of my version of the Splitwise app. This prototype was then used to test and validate my designs with users.

Before & After Comparison

Here is a comparison of the pain points and my recommended solutions:
Pain Point #1: Adding a bill
There was no option to review your bill prior to saving, which led users to be hesitant in submitting their bill.
Allow users the option to review the bill breakdown after saving the bill by reusing the “Details” screen and placing it earlier in the task flow.
Pain Point #2: Adjusting split options
  • Choosing the correct option to split the bill is difficult due to the lack of intuitive information hierarchy.
  • Users were unsure how to use certain features like “split by adjustment” or “split by share” and ended up ignoring it. 
  • Adjust the information hierarchy by re-grouping the split options based on similar outcomes (e.g. splitting vs. owing the entire bill). This allows users to more easily skim and select the correct option.
  • Add descriptions for product features that are less intuitive and a sticky button above the keyboard for easy saving.
Pain Point #3: Reviewing bills
Users often doubted the accuracy of the cost breakdown due to poor readability and confusing language.
Add color, spacing, and slight copy tweaks to improve reading comprehension and readability.

Test & Validate

I sought out 6 more users to validate my changes. Through this testing, I observed the following:

Closing Thoughts

Usability testing made a significant impact on how much information I was able to uncover around the pain points of users and their mental models approaching the issue of splitting bills.

The exercise of using a 2×2 matrix also proved to be effective in prioritization. I recommend using this tactic to make sure all key stakeholders understand the primary scope of work and the low hanging fruits to execute against for maximum impact to both the user and the business.
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