The triple-lock guarantee on state pension increases will be protected up until 2025 if Labour wins the next election, the opposition has promised.
Shadow chancellor John McDonnell has put the commitment on a pensioners' pledge card, along with other promises aimed at wooing older voters.
Labour will also promise compensation for women hardest-hit by increases in the state pension age, protection for elderly Britons living overseas, and a commitment to keep winter fuel payments and free bus passes.
The triple-lock mechanism guarantees that the state pension increases annually by the highest measure out of average wages, inflation, or 2.5%.
Chancellor Philip Hammond's Autumn Statement gave a signal that while the triple-lock is safe for now, it may not be immune from cuts in the longer term - which Labour believes offers the opportunity to win over older voters.
The party said the commitment to maintain the triple-lock would increase pensioners' incomes by at least £650 between 2021/22 and 2023/24, compared with increasing the state pension in line with inflation.
House of Commons Library analysis showed that for those on the basic state pension, the triple-lock will be worth £652.60 over the period, while for those on the new state pension the guarantee will be worth £852.80.
Mr McDonnell said: "I am delighted to be launching this pledge card that will inform many elderly people in our communities that Labour is not only promising to stand up for pensioners, but is determined to ensure they keep the hard-won entitlements they currently hold.
"It's a national scandal that pensioner poverty is rising and the Tories are refusing to commit to keeping the triple-lock or compensate women worst affected by the speeding up in the state pension age.
"Only a Labour government will stand up for pensioners and protect them throughout the next parliament."
The pledge card will be launched by the shadow chancellor during a visit to Coventry.
A pledge card listing eye-catching policies was used by Labour in the run-up to the 1997 landslide victory under Tony Blair, and repeated at subsequent general elections.
Labour's latest promises were dismissed by the Tories, who claimed that pensioners would suffer because Jeremy Corbyn's party would "crash" the economy by failing to control public finances.
Conservative MP Kelly Tolhurst said: "Labour's economic mismanagement hit older people hard when they were in government, and Jeremy Corbyn and John McDonnell's reckless plans would do the same all over again.
"Our careful management of the economy, changes to help people save more for their retirement, and protections for pensioner benefits and the state pension are all helping people have dignity and security in retirement."