How much of the context window am I paying for?
Need to see how much of the context window you're using and paying for? Tokens are the unit AI providers bill in, and getting the count wrong throws off every cost estimate. This page helps teams auditing prompt efficiency get an accurate count and the cost that follows from it.
Results update automatically as you type.
- Tokens used
- 20,000 tokens
- Context window
- 128,000 tokens
- Used
- 15.6%
- Remaining
- 108,000 tokens
Why this isn't trivial
The part people underestimate: you pay for the tokens you send, not the window size, so knowing your real usage reveals waste. In practice the biggest savings come from removing unused context to cut the tokens you actually pay for, so it is worth modelling before you commit.
How it's calculated
We estimate this by comparing tokens used against the window and pricing the used portion. Every figure uses the current provider prices baked into the site (reviewed daily), and you can override any input to match your own assumptions.
Frequently asked questions
Do I pay for the whole window?+
No — only for tokens you send, so trimming unused context saves directly.
What's a good usage level?+
Enough to answer well without padding; audit for context the model ignores.
Are these prices up to date?+
Yes. The model prices behind this calculator are refreshed and reviewed daily, so your estimate reflects current provider rates rather than a stale snapshot.
Related
Estimates for planning. Pricing data last reviewed 28 July 2026.