Text Entry on Tiny QWERTY Soft Keyboards


Wearable devices (e.g., smartwatches, smartglasses, and digital jewelry) featuring a touchscreen are becoming widely available to consumers. On these devices, entering text with a qwerty soft keyboard is troublesome mainly because of the very small screen space. However, qwerty keyboards have the advantage that users are already familiarized with the layout and the input technique is easy to understand. Motivated by this fact, we conduct fundamental research on this topic using 3 qwerty-based soft keyboards for 3 different screen sizes. In addition to ZoomBoard (a soft keyboard for diminutive screens), we propose a callout-based soft keyboard and ZShift, a novel extension of the Shift pointing technique.

We conducted a comprehensive user study followed by extensive analyses on performance, usability, and short-term learning. Our results show that different small screen sizes demand different types of assistance. In general, manufacturers can benefit from these findings by selecting an appropriate qwerty soft keyboard for their devices.

We also investigated 3 simple mechanisms to auto-correct typing errors as they go, at the word level: spell checker with n-best lists, language models, and a combination of both. These mechanisms have potential for wearable devices, which have limited autonomy and limited computing capabilities, even when paired to a smartphone.

In sum, this work provides designers, researchers, and practitioners with new understanding of qwerty soft keyboard design space and its scalability for tiny touchscreens, together with a series of simple but efficient error auto-correcting mechanisms for tiny touch-capable devices.


Source Code

The keyboard prototypes are web-based and should work on all major browsers.


Our software is free for scientific use (MIT license). The software must not be distributed without prior permission of the authors. Please contact us if you are planning to use the software for commercial purposes. The authors are not responsible for any implication derived from the use of this software.

ZoomBoard was developed by S. Oney, our version was adapted for conducting the paper experiments. You can download the source code of the original ZoomBoard prototype at github.

Live Demos

Try yourself the keyboard prototypes within your web browser, either desktop or mobile based:


If you use the code (or a derivation thereof) in your work, please cite as

  • L. A. Leiva, A. Sahami, A. Catalá, N. Henze, A. Schmidt. Text Entry on Tiny QWERTY Soft Keyboards. Proceedings of the SIGCHI conference on Human Factors in Computing Systems (CHI), 2015.

LaTeX users can use the following BibTeX entry for citation:

  author    = {Luis A. Leiva and Alireza Sahami and Alejandro Catalá and Niels Henze and Albrecht Schmidt},
  title     = {Text Entry on Tiny QWERTY Soft Keyboards},
  booktitle = {Proceedings of the SIGCHI conference on Human Factors in Computing Systems (CHI)},
  year      = {2015},