BRUSSELS—European Union sanctions on Russia over the Ukraine crisis will have only a modest impact on Europe’s economy this year and next but hit Russia’s growth rate harder, according to an EU analysis seen by The Wall Street Journal.

EU member states decided Tuesday to maintain their current sanctions, which include restrictions on trade with Russia’s defense, financial, and energy sectors, after a promised review. Diplomats said there was broad consensus at a meeting of EU ambassadors that there were no grounds for easing...