Abstract: Large displays are often constructed by tiling multiple small displays, creating visual discontinuities from inner bezels that may affect human perception of data. Our work investigates how bezels impact magnitude judgement, a fundamental aspect of perception. Two studies are described which control for bezel presence, bezel width, and user-to-display distance. Our findings form three implications for the design of tiled displays. Bezels wider than 0.5cm introduce a 4--7% increase in judgement error from a distance, which we simplify to a 5% rule of thumb when assessing display hardware. Length judgements made at arm's length are most affected by wider bezels, and are an important use case to consider. At arm's length, bezel compensation techniques provide a limited benefit in terms of judgement accuracy.