GPT-3.5 Turbo Instruct API Pricing
OpenAI · context window 4K · prices updated 2026-09-29
Where GPT-3.5 Turbo Instruct sits on price
At $2.00 per million output tokens, GPT-3.5 Turbo Instruct is a mid tier model — right at the median output price of $2.20, which puts it cheaper than 55% and pricier than 45% of the models we track. It sits 29th cheapest of the 100 OpenAI models we track. Output is only 1.3× the input price, an unusually flat spread: long prompts hurt about as much as long answers, so prompt size is where the savings are.
What real workloads cost on GPT-3.5 Turbo Instruct
These three workloads are the ones teams actually run on a mid-priced model — a $2.00/1M model is not bought for the same job as one ten times the price.
| Workload | Per request | Per month |
|---|---|---|
| Support chatbot — 500 conversations/day (5K in / 1.4K out) Conversation history re-sent each turn — the classic prompt-caching win. | $0.0103 | $155 |
| Document pipeline — 10K docs/day (3K in / 500 out) Batch-friendly: no user waiting, so a ~50% batch discount usually applies. | $0.0055 | $1650 |
| Small app — 1K requests/day (500 in / 150 out) The baseline most side projects actually run at. | $0.001 | $31.50 |
Model your exact traffic in the API cost calculator — it preloads GPT-3.5 Turbo Instruct with caching and batch options.
GPT-3.5 Turbo Instruct price history
GPT-3.5 Turbo Instruct's price has not moved since we began tracking it on Aug 2, 2026 — 58 days of stability in a market where 88 of the 353 models we track have repriced over the same period, including 12 of OpenAI's own 100 models.
Change-points from our daily price snapshots (tracking since Aug 2, 2026; intraday moves between snapshots are not captured).
GPT-3.5 Turbo Instruct vs Devstral 2 2512
The closest-priced alternative from another vendor is Devstral 2 2512 (Mistral) — priced within a rounding error on output, with $1.10 less per million input tokens. When two models land this close on price, the decision is quality on your own workload, not the price sheet: run 50 real requests through both and compare.
See Devstral 2 2512 pricing →Cheaper alternatives
More OpenAI models
Frequently asked questions
› How much does the GPT-3.5 Turbo Instruct API cost?
GPT-3.5 Turbo Instruct costs $1.50 per million input tokens and $2.00 per million output tokens and no discounted cached-input tier. That works out to roughly 500,000 output tokens per dollar.
› What does the support chatbot workload cost on GPT-3.5 Turbo Instruct?
Support chatbot — 500 conversations/day (5K in / 1.4K out) costs about $0.0103 per request and $155 per month on GPT-3.5 Turbo Instruct. Conversation history re-sent each turn — the classic prompt-caching win.
› What does it cost to fill GPT-3.5 Turbo Instruct's 4K context window?
Sending 4K of input in a single request costs $0.0061 at $1.50 per million tokens — before any output. There is no cached-input tier on this model, so every repeat of that context is billed at full price. This is why large context windows are cheap to advertise and expensive to actually use.
› Is GPT-3.5 Turbo Instruct worth the price?
GPT-3.5 Turbo Instruct sits in the middle of the market (29 of 100 by price within OpenAI). The honest test is a routing experiment: send the same 200 real requests to this model and to a tier below, and compare failure rate against the price gap — most teams find a majority of traffic never needed the pricier model.