Usually, but it's tighter than it feels. For an international departure from Changi, our model's typical (median) door-to-gate time is about 73 minutes at midday, rising to around 90 minutes at evening peak - and the busier-than-usual (90th percentile) case reaches 89-114 minutes. Two hours (120 minutes) covers the typical case comfortably but leaves less margin than most travellers assume during evening peak or with checked bags.
Changi is efficient by global standards - it's why the numbers above are lower than many other major hubs. But "2 hours is plenty at Changi" as a blanket rule ignores time of day, which terminal you're in, and whether you're checking a bag.
Use the estimate below with your real time, terminal, and bags for a specific answer instead of a rule of thumb.
These are general, statistically-modelled estimates - not a guarantee. Always allow extra time for anything unusual, and check your airline's and airport's own current guidance.