DAWs and dedicated audio editors usually have tools that allow for gradual tempo changes, say 50% over 30 seconds. If BIAB can do that, I've never seen it but there are inexpensive tools that can do this with your finished audio.

As has been mentioned, you're still doing math so that you can calculate the finished result.


BIAB 2024 Audiophile Mac
24Core/60CoreGPU M2 MacStudioUltra/8TB/192GB Sequoia, M1 MBAir, 2012 MBP
Digital Performer11, LogicPro, Finale27/Dorico/Encore/SmartScorePro64/Notion6 /Overture5