One of the billionaire bosses of one of Australia’s most successful start-ups says he’ll give away half of his $7 billion fortune.

The Giving Pledge is a promise by the world’s wealthiest people to dedicate the majority of their wealth to charitable causes.

The couple have also signed up for the London-based not-for-profit, Founder’s Pledge, committing to give away 25 per cent of their wealth over the next five years.

“We particularly like the disciplined approach that the Founder’s Pledge takes towards giving – it’s a good muscle to build into normal operations,” he told the paper.

“The vast majority of our wealth is still embodied in Canva, so as it continues to grow so does our potential impact.

“We feel an immense responsibility to put the value of Canva back into serving our communities and the world.”

In the last few years, the couple has already donated “tens of millions” to support biodiversity causes and climate start-ups, the paper reported.

They are especially interested in environmental causes, and former zoologist Miller already runs “nature positive” financier, Wedgetail.

“Lisa’s background as a zoologist and her work at the Australian Museum give her deep roots in this space, and her love of animals and the environment has rubbed off on me, and our whole family,” Adams said.

“Our focus really crystallised during the devastating 2019 east coast bushfires when we read that an estimated three billion animals died or were displaced,” he said.

“That was a pivotal moment for us to start putting our plans together, and it inspired Lisa to focus full-time on establishing Wedgetail and regenerative work.”

Adams is the Chief Product Officer of the company, which he started with Melanie Perkins and Cliff Obrecht.

It offers online design tools and was launched in 2013.

The other founders are also giving away much of their wealth via The Giving Pledge. Last year they handed out $19 million.