Foreign Minister Urmas Reinsalu made his comments in an interview with Reuters during a trip to Kyiv with six other foreign ministers.
The visit was intended to show support for Kyiv as it struggles with power outages following a wave of drone and missile strikes by Russia, which invaded Ukraine in February.
"We would like to see European countries doubling their defence expenditure in the time of the Ukrainian war and after the war, and we are going to spend 3% of our GDP on national defence," he said.
NATO Secretary-General Jens Stoltenberg said last week that countries in the military alliance, of which Estonia is a member, may decide to aim to spend more on defence than their current target of 2% of national output.
Many NATO allies have already increased their military spending since Russia's invasion of Ukraine in February.
Ukraine, which is not a NATO member but has applied to join the alliance, has increasingly called for support from its Western allies since Russian increased its missile strikes on Ukrainian energy infrastructure.
Reinsalu said the 27-nation European Union, which includes Estonia, should also increase the level of funding it earmarks in military support for Ukraine.
"The European Union combined has supported around 0.2% of its GDP to military assistance to Ukraine and I made a pledge if we could reach 1% it would make a grand difference on the ground in changing the course of the war," he said.
Ukrainian Prime Minister Denys Shmyhal wrote on Twitter that Monday's trip by Reinsalu and the six other ministers had included discussion of tightening EU sanctions, rebuilding Ukrainian energy infrastructure, financial support and Ukraine's "Euro-Atlantic aspirations."
(Reporting by Tom Balmforth; editing by Timothy Heritage)
By Tom Balmforth
