The four leaders discussed the meeting in a phone call Sunday as part of their efforts to achieve a "comprehensive settlement" in the conflict between Ukrainian forces and pro-Russian rebels, Berlin said.
Russia President Vladimir Putin, however, warned that the summit planned in the Belarussian capital Minsk would only take place if the leaders agreed on a "number of points" by then.
"We will be aiming for Wednesday, if by that time we manage to agree on a number of points which we've been intensely discussing lately," Putin told Belarus President Alexander Lukashenko in televised remarks on Sunday.
Merkel and French President Francois Hollande have ramped up their push for peace in recent days, jetting to Kiev first for talks with Ukrainian President Petro Poroshenko and then to Moscow to meet Putin, who the West accuses of masterminding the 10-month-old conflict.
On Monday, foreign ministry officials from the four countries will hold preparatory talks in Berlin while Merkel briefs US President Barack Obama on the latest peace initiative during a visit to the White House.
In their telephone conversation on Sunday, Putin, Poroshenko, Merkel and Hollande "continued to work on a package of measures to achieve a comprehensive settlement of the conflict in eastern Ukraine," Merkel's office said.
The Ukrainian government said the leaders expected their efforts to lead to "an immediate and unconditional bilateral ceasefire".
Fresh fighting claimed 12 civilian lives, separatist and Kiev authorities said, with 12 Ukrainian troops also killed in the last 24 hours.
The conflict in the former Soviet republic has left at least 5,400 people dead.
A previous peace deal agreed in Minsk in September has been largely ignored, with fighting escalating in recent weeks as the rebels push further into government-held territory.
French Foreign Minister Laurent Fabius told a security conference in the German city of Munich that "what Germany and France are seeking right now is not peace on paper, but peace on the ground."
European Union foreign ministers meeting in Brussels on Monday are to confirm the addition of 19 people to a list of EU sanctions over the conflict in Ukraine.
Divisions over arming Ukraine
In Washington, Obama is set to host Merkel as the worsening violence confronts them with a choice between pursuing the risky peace talks or throwing more weapons into the war.
At home Obama is facing increasing calls to supply the outmatched Ukrainian army with more weapons to shore up its faltering defences.
But Merkel and many European nations believe weapons could not overturn the military mismatch between Ukraine and the might of the Russian army, and would simply escalate the conflict.
"I think that the progress Ukraine needs won't be achieved with even more weapons," Merkel told the Munich conference on Saturday.
"I am very, very doubtful."
Also speaking in Munich, US Secretary of State John Kerry dismissed talk of a rift with Europe on the issue.
"Let me assure everybody, there is no division, there is no split," Kerry said.
"We all agree that this challenge will not end through military means (but) the longer it takes, the more the off-ramps are avoided, the more we will be forced to raise the costs on Russia and its proxies."