In Beijing, it was one centimetre.
In London, multiply that by 30.
Canada's big man delivered the first truly huge let down of the Olympics on Friday night, as shot putter Dylan Armstrong finished in fifth place and 30 centimetres off the podium less than a year after winning silver in the world championships.
His best throw of the day – 20.93 metres – was a long way off of his personal best and even further from the heavy expectations placed on him as the country's lone legitimate medal threat in track and field.
While Armstrong managed to put a brave face on yet another crushing outing four years after unexpectedly finishing fourth in his Olympic debut, he and Athletics Canada were clearly expecting more.
"It's tough," Armstrong said, acknowledging an elbow injury in February had set back his training. "Fourth in Beijing. Fifth here. We'll have to think about [the 2016 Games in] Rio. I don't know yet. I'll be 35 years old when that comes around."
Athletics Canada head coach Alex Gardiner was rather frank in his assessment of what went wrong afterwards, noting that he was concerned Armstrong was off his game that morning when he came up well short until his final throw in qualifying.
Between all nine attempts on the day, Armstrong never matched the 21.04 metres he threw in Beijing, a mark he had since bettered roughly 50 times in competition.
"He was really, really nervous this morning," Gardiner said, calling the performance flat and not inspired. "And I don't think he shook all of that off."
Part of those nerves may have stemmed from the pressure put on Armstrong the past four years, time with which he's had to mull missing a medal by a centimetre and also watch his profile grow astronomically, in his home country and abroad.
Armstrong, after all, is one of the Canadian athletics team's only household names and has become a star internationally en route to winning the Diamond League circuit last year.
That left an Olympic podium as the final, defining accomplishment to pull off in his sport.
But no Canadian has ever won a medal in shot put – or in any throwing sport in 100 years – and this was a field so strong that many oddsmakers had Armstrong running fourth or fifth heading in.
That was ultimately how it went, too, with favourites like Poland's Tomasz Majewski and Germany's David Storl putting up several tosses of nearly 22 metres en route to gold and silver.
Another contender, Reese Hoffa of the United States, appeared to have similar jitters to Armstrong but had an early throw of 21.23 that held up for bronze.
"There's probably nothing harder than to medal at an Olympic Games," Hoffa said of their event. "I take my hat off to Tomasz and David. They have figured out the puzzle."
Armstrong, meanwhile, simply looked puzzled out in the middle of Olympic Stadium, with his final three throws all going well left and substantially shy of 21 metres.
Despite the obvious letdown, the 6-foot-4, 310-pound native of Kamloops was his cheerful self in meeting with the media afterward, even as he lamented what could have been.
"It would have meant everything to strike gold here," he said. "It's like winning the lottery, man. It really is. What can happen when you win a gold."
"He had a lot of hopes riding on him," Gardiner explained. "We tried to pull back on those, but he had sponsors, he had family, he had the whole city of Kamloops. And I don't know what that does to you. But it's got to do something."
Armstrong now will likely never personally know what happens when you win that Olympic lottery, but he certainly has experience with the near-miss and its particular cruelty.
In Beijing, however, his fourth place came out of nowhere, and it became an unexpected boost that increased his profile and helped propel him to become one of the top five or six throwers in the world.
Here, there's not that silver lining, not with 2016 so far – maybe even too far – away and shot put set to fade back into relative obscurity, at least at home.
No, London was his one big chance, and he fell just short once again.
And having only the one big chance may have even been why he didn't deliver.
"Fourth or fifth at the Olympics, at the end of the day, I can deal with that," Armstrong said. "At least it wasn't by a centimetre this time, if you want to look at it that way."