The event, which has brought more than 450 bands to the city, was under threat because of funding cuts.
Organisers set up funding page so they could raise enough money to stage the festival next summer.
And music fans dug deep by pledging £6,000 in just nine days so the event could go ahead.
Long Division founder Dean Freeman said: “We set out to raise £6,000 in 42 days to ensure Long Division continued into 2016. I am thrilled that is only took us nine days.
“Now we have reached the £6,000, we feel confident to push ahead with the festival and hopefully Long Division 2016 can be the best yet.”
Northern Irish rockers Ash headlined the fifth Long Division festival in June this year.
Other acts who have played at the event include The Cribs and Fat White Family.
Mr Freeman has now set a new fundraising target of £10,000 to help make next year’s event the best yet.
To donate, log onto www.crowdfunder.co.uk/longdivision2016.