Type 1 Back to basics - ratios

Hi everyone, hope you’re all well

I’m having a bg wobble and have been checking my basal rates etc.

Can someone remind me how to check my carb:insulin ratio?

I’ve always been 10g:1 unit but find I’m doing lots of corrections. It’s been so long since I last did it I can’t remember the best process.

Thanks guys!

Nomi