Cost per GPU hour is the effective price of renting one GPU for one hour. It's the universal comparison metric for GPU cloud pricing.
Why do we need it? Because providers price instances differently:
- Lambda sells 1×H100 for $2.49/hr → cost per GPU hour = $2.49
- AWS sells 8×H100 for $98.32/hr → cost per GPU hour = $98.32 ÷ 8 = $12.29
- Some providers bill per-minute or per-second
Without normalization, you'd compare $2.49 to $98.32 and think AWS is 40× more expensive. In reality, it's about 5× more per GPU — still significant, but a completely different story.