The formula links firefighters' pay to the upper quartile of average male manual earnings. The Fire Brigades Union heard on Tuesday the calculations had generated a figure of 1.4%.
If the formula had thrown up a figure above the 1.5% public sector pay limit the employers would have faced a difficult choice between challenging the government to satisfy the firefighters or sticking to the limit and risking costly strikes.
Although the firefighters will receive 0.1% less than other local government groups the FBU presented the award as a victory in the battle to preserve the pay formula.
The employers have also given a commitment to honour the pay formula next year.
The 1.4% award adds about £10 million to the £730m fire service pay bill and around £4.50 a week to the average firefighter's £320 weekly pay.
Until Tuesday no-one knew what the formula figure was. There was widespread speculation that it was likely to be slightly above 1.5%.
The employers had said they would not exceed 1.5% but there were suggestions recently that if the formula had given rise to a higher figure the employers might have agreed to arrangements to pay the difference in stages.