FREE TOOL · PRICES VERIFIED AUGUST 31, 2026

OpenAI API Pricing

Every current GPT model with its real per-million-token price — input, output, and cached input — plus a calculator for your own workload and a straight comparison against Claude and Gemini.

MODELS
6
INPUT FROM
$0.20/1M
OUTPUT UP TO
$30.00/1M
MAX CONTEXT
1.05M
ESTIMATE YOUR WORKLOAD
MODELINPUT $/1MCACHED INOUTPUT $/1MBLENDEDCONTEXTYOUR COST
GPT-5.6 Sol
gpt-5.6-sol · ≥272K: 2×/1.5×
$4.00$0.40$20.00$8.001.05M$14.00
GPT-5.6 Terra
gpt-5.6-terra · ≥272K: 2×/1.5×
$2.00$0.20$12.00$4.501.05M$8.00
GPT-5.5
gpt-5.5 · ≥272K: 2×/1.5×
$5.00$0.50$30.00$11.251.05M$20.00
GPT-5.6 Luna
gpt-5.6-luna · ≥272K: 2×/1.5×
$0.20$0.02$1.20$0.451.05M$0.80
GPT-5.4 Mini
gpt-5.4-mini
$0.75$0.075$4.50$1.69400K$3.00
GPT-5.4 Nano
gpt-5.4-nano
$0.20$1.25$0.463400K$0.82

USD per 1M tokens from OpenAI’s official pricing page as of August 31, 2026. Blended assumes a 3:1 input:output ratio. Get keys at the OpenAI console.

HOW OPENAI PRICING WORKS

Three tiers, one cache discount, and a new long-context catch.

The GPT-5.6 line is a three-step ladder: Sol is the frontier flagship, Terra the workhorse at half the price, and Luna the fast tier at a twentieth. All three share the same 1.05M-token context window. The older GPT-5.4 Mini and Nano stay on the price list for legacy workloads.

New in the 5.5/5.6 era: a long-context surcharge. Prompts beyond 272K input tokens bill the whole request at 2× input and 1.5× output — and it applies on Batch and Flex too. If you routinely fill a large share of that 1.05M window, price your workload at the surcharge rate.

Cached input is the discount that matters: resend the same prompt prefix and OpenAI bills those tokens at about a tenth of the fresh-input rate (the pricing page now also lists a per-model cache-write fee). For agents and RAG apps with a long, stable system prompt, caching often cuts the input side of the bill by 80–90%.

For anything that can wait, the Batch API processes requests within 24 hours at half price on both input and output, and the Flex service tier gets the same 50% off synchronously when latency doesn’t matter — the cheapest ways to run evaluations, backfills, and bulk classification on GPT.

How much does the OpenAI API cost?

OpenAI bills per token, with separate input and output rates quoted per million tokens. The current GPT-5.6 line runs from $0.20 input / $1.20 output per 1M tokens on Luna up to $4 / $20 on Sol, with cached input at roughly a tenth of the fresh rate. The table above has every current model.

What is the cheapest OpenAI model?

GPT-5.4 Nano at $0.20 input / $1.25 output per 1M tokens, essentially tied with GPT-5.6 Luna ($0.20 / $1.20). Luna is the better default — same price class, newer model, full 1.05M context, and the deepest cache discount at $0.02 per 1M cached input tokens.

How does cached input billing work on OpenAI?

When a request repeats a prompt prefix the API has recently seen (system prompts, few-shot examples, long documents), those tokens bill at the cached rate — about 10× cheaper than fresh input. Caching happens automatically, with a per-model cache-write fee listed on the pricing page. The savings show up in the cached_tokens field of the usage object.

Is GPT cheaper than Claude or Gemini?

Tier for tier, GPT-5.6 sits between them: Sol ($8/1M blended) costs less than Claude Opus 5 ($10) but more than Gemini 3.1 Pro ($4.50), while Terra ($4.50) lands right between Claude Sonnet 5 ($4) and Gemini 3.7 Flash ($1.50). The matchup table below compares all three, tier by tier.

Does the OpenAI API have a free tier?

No — API usage is pay-as-you-go from the first token (new accounts occasionally get trial credits). A ChatGPT Plus or Pro subscription is a separate product and includes no API allowance.

HOW OPENAI STACKS UP

GPT vs. its closest rivals, tier by tier

BLENDED $/1M · 3:1 IN:OUT
FLAGSHIP
GPT-5.6 Sol
$8.00/1M
Claude Opus 5
$10.00/1M
Gemini 3.1 Pro
$4.50/1M
COMPARE
WORKHORSE
GPT-5.6 Terra
$4.50/1M
Claude Sonnet 5
$4.00/1M
Gemini 3.7 Flash
$1.50/1M
COMPARE
SMALL / FAST
GPT-5.6 Luna
$0.45/1M
Claude Haiku 4.5
$2.00/1M
Gemini 3.5 Flash-Lite
$0.85/1M
COMPARE

Also see: Claude API pricing · Gemini API pricing · Grok API pricing · DeepSeek API pricing · Kimi API pricing · GLM API pricing · MiniMax API pricing · MiMo API pricing · all 58 models

BUILDING ON THE OPENAI API?

Your users will spend these tokens. Meter them per API key.

ReqKey gives every key a credit balance — validate, deduct, enforce limits, and watch per-consumer GPT spend in real time.