Background: The 6 min walk test (6MWT) is the gold standard for field-based functional assessment, yet the 3 min walk test (3MWT) offers a time-efficient alternative. However, a lack of localised normative reference values (NRV) and an over-reliance on simple 6 min extrapolation limit its clinical utility. Objectives: To establish the NRV and reference equations for the 3MWT in a healthy cohort and investigate the physiological relationship between 3 min performance and 6 min predictions. Methods: This cross-sectional study recruited healthy community-dwelling adults (aged 20 to 80, BMI < 27.5 kg/m²). Participants performed two 3MWT trials on a 30 m indoor course. Primary outcomes included the best 3MWT and physiological parameters. Reference equations were derived using multiple linear regression. Results: In total, 240 participants were recruited with an overall median 3MWT of 290 metres (m) (IQR 257.0–323.0). Males walked significantly farther than females (p = 0.002). While 3MWT remained stable across age decades in males (p = 0.225), females’ performance declined with age (p = 0.005). Older adults maintained walking distances comparable to younger cohorts by operating at a higher relative percentage of their predicted maximum heart rate and exhibiting prolonged recovery profiles. Doubling the 3MWT significantly overestimated 6 min capacity (p < 0.001), highlighting non-linear pacing strategies. Conclusions: This study provides the first age- and gender-specific NRV for the 3MWT in Singapore, supporting its use as a rapid functional walking assessment tool in healthy adults. The findings suggest that the 3MWT should not be interpreted as a direct linear surrogate for the 6MWT. Further research is required to validate these reference equations externally and determine their clinical sensitivity in disease populations.