The AI API billing-units zoo
Seventeen meters in three layers, plus a modifier layer that changes rates, not units.
Consumption units
1-10
1
Text tokens
Per tokenizer
2
Reasoning tokens
Invisible output
3
Cached tokens
1.25x write, 0.1x read
4
Media-input tokens
Image, audio, PDF
5
Realtime audio tokens
100 ms per token
6
Aa
Characters
TTS and guardrails
7
Minutes / seconds
STT, video, music
8
Output objects
Images, songs, tasks
9
Requests
Search and grounding
10
Pages
OCR, document AI
Time and capacity units
11-16
11
GPU-seconds
Priced by card
12
Container-hours
5-min minimum
13
GB-days
File storage
14
Token-hours
Cache storage
15
PTU-hours
Reserved capacity
16
Training tokens
Epochs multiply
Synthetic wrappers
17
17
Credits / CCUs
A scalar over the real rate card: 100 CCU = $1.00 on AWS Marketplace, and subscription credits work the same way
Modifiers
Change the rate, not the unit
×0.5
Batch tier
×0.5
Off-peak clock
×1.1
US-pinned inference
×2
Fast service tier
×36
Quality knob
Step
Long context >200k
Cliff
After free quota
Multipliers stack: cached, batch,
and US-pinned apply at once.