In the SpeakOut! WordPress Petition plugin it is possible to set a goal for how many signatures you wish to collect. This can be displayed as a bar graph.

It is possible to have the goal automatically increase when you reach a specified percentage of your goal.

In dashboard > SpeakOut! > petitions > edit > petition options there is an option to set the signature goal

Check the box and it reveals another option to auto increase goal

selecting that reveals some options

This is pretty self-explanatory. However you may not want to have to update manually.

If you would like SpeakOut! petition plugin to manage the goal increase automatically set the auto increase by value to 0

When your trigger % is reached e.g. 85%, SpeakOut! will do some calculations and add around 50% to your goal, also rounding it so the goal is “pretty” e.g. 1,500, instead of a literal calculation that could end up being 1,432

There is a webhook associated with this