A study evaluating the impact of the route on the community in the north of Scotland also found it resulted in 180 full-time equivalent jobs being created.
The research, by the Moffat Centre for Tourism at Glasgow Caledonian University, found an additional £13.5 million was spent on accommodation, activity and retail along or near the route throughout 2018.
Tourism-related businesses along the route also reported a 16% uptick in business between 2017 and 2018.
Hotels saw room occupancy rates jumping from 52% in 2014 to 78% in 2018.
David Whiteford, chairman of the North Highland Initiative, said: "From the very beginning, the North Highland Initiative's aim in creating the North Coast 500 was to market the north
Highland area's wonderful tourism offerings in a way that would stimulate economic growth.
"The North Coast 500 is now one of the top reasons for people to travel to Scotland, and with the stunning scenery, unique experiences, exceptional food and drink, the famous Highland hospitality, a wide range of activities and the fascinating history and heritage the north Highlands of Scotland has to offer, this is no surprise.
"The North Coast 500 has been the subject of a number of studies and surveys over the years, but none as comprehensive as the Moffat Centre's official North Coast 500 evaluation report.
"The findings within this report are so encouraging to see, with businesses throughout the north Highlands succeeding, developing and growing with the NC500 brand.
"Moving forward, we are very aware that the significant growth reflected here must be managed and not be at the expense of any community.
"Instead we want to see people and businesses across the north Highlands benefiting from the investment in the area and the increased attention brought by the North Coast 500.
"It is a once-in-a-generation chance to boost the area if we all work together and make the most of this opportunity.
"It is the North Highland Initiative's ambition to continue working with the Scottish Government, Highlands and Islands Enterprise and other external agencies in order to support communities throughout the North Highlands, and to ensure the ongoing growth of the NC500 route is sustainable."
Despite the economic boost, some locals have raised concerns about congestion, speeding and pressures on infrastructure on the route, which was re-branded in 2015.