To calculate All Time Budget, you take the entire total media spend for a specific time period and you add it up.
EXAMPLE: Tedy needed to find out the total media spend for 2017 for three of the ninety-six campaigns that ran on his DSP.
Campaign (1) total media spend was $19,874.92, campaign (2) total media spend was $24,584.08 and campaign (3) the total media spend was $48,732.34.
The All Time Budget that Tedy spend in 2017 on the three campaigns is $93,191.34.