Cost of living in Portsmouth (United Kingdom) is 47% more expensive than in Zaragoza (Spain)
This comparison is lacking data. It provides a decent comparison, but it is not yet reliable. It is based on 284 prices entered by 39 different people.
For example, you would need at least €4,121 (£3,672) in Portsmouth to maintain the same standard of living that you can have with €2,800 in Zaragoza.