OpenAI API Pricing Guide 2026

OpenAI API pricing is usage-based: you pay per million tokens processed. This guide covers current rates for all major models, cost calculation examples, and how to reduce your OpenAI API bill with APIMaster.ai.

OpenAI API Pricing Table (Official Rates)

Model	Input (per 1M)	Output (per 1M)	Cached Input
GPT-5	$15.00	$60.00	$3.75
GPT-4o	$5.00	$15.00	$1.25
GPT-4o mini	$0.15	$0.60	$0.075
o3	$10.00	$40.00	$2.50
o4-mini	$1.10	$4.40	$0.275
GPT-4o Realtime	$5.00	$20.00	—

Rates from OpenAI. Check OpenAI pricing page for latest.

Discounted OpenAI API Pricing via APIMaster.ai

APIMaster provides the same OpenAI models at discounted rates through an aggregated relay with fingerprint verification.

Visit the APIMaster marketplace for live prices on each model tier.

Typical savings: 30–70% off official OpenAI rates, depending on model and tier.

How OpenAI API Pricing Works

What Is a Token?

1 token ≈ 4 characters of English text:

• "Hello, world!" = 4 tokens
• A 750-word essay ≈ 1,000 tokens
• Average API call: ~500 input + 300 output tokens

Input vs Output Tokens

OpenAI charges separately for input (your messages) and output (the response). Output tokens are typically 3–4× more expensive than input tokens.

Example:

• 10,000 API calls/day
• Avg 800 input + 400 output tokens per call
• Monthly usage: 240M input + 120M output tokens
• GPT-4o cost: 240 × $5 + 120 × $15 = $1,200 + $1,800 = $3,000/month
• GPT-4o via APIMaster: significantly lower—see marketplace for current rates

Prompt Caching

OpenAI's prompt caching reduces costs by 75% for repeated context (system prompts, long documents). Cached input tokens are billed at 25% of the standard input rate.

APIMaster passes through caching pricing where supported.

Cost Optimization Strategies

1. Choose the Right Model

Don't use GPT-5 where GPT-4o mini will do:

Task	Recommended Model	Approx. Cost vs GPT-5
Classification, extraction	gpt-4o-mini	~100× cheaper
Customer support, Q&A	gpt-4o	~12× cheaper
Complex analysis, research	gpt-5	baseline
Real-time math/science	o3 or o4-mini	depends

2. Use Prompt Caching

Place static content (instructions, reference docs) at the beginning of your prompt to maximize cache hits:

# The long system prompt is cached after the first call
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system", "content": LONG_SYSTEM_PROMPT},  # cached
        {"role": "user", "content": user_message},            # not cached
    ],
)

3. Truncate Long Contexts

Token usage scales linearly with context length. Summarize or truncate conversation history for long sessions:

def trim_history(messages, max_tokens=4000):
    # Keep system prompt + last N messages
    if len(messages) > 10:
        return [messages[0]] + messages[-9:]
    return messages

4. Batch Requests

For non-real-time tasks, OpenAI's Batch API offers 50% off standard prices with 24-hour turnaround. APIMaster supports batch-compatible workflows.

OpenAI API Cost Calculator

Quick formula:

cost = (input_tokens / 1_000_000 × input_price) 
     + (output_tokens / 1_000_000 × output_price)

Python cost estimator:

def estimate_cost(input_tokens, output_tokens, model="gpt-4o"):
    prices = {
        "gpt-5":      (15.00, 60.00),
        "gpt-4o":     (5.00, 15.00),
        "gpt-4o-mini": (0.15, 0.60),
        "o3":         (10.00, 40.00),
    }
    inp, out = prices.get(model, (5.00, 15.00))
    return (input_tokens / 1e6 * inp) + (output_tokens / 1e6 * out)

print(f"${estimate_cost(1_000_000, 500_000, 'gpt-4o'):.2f}")

Reduce Your OpenAI API Bill

APIMaster.ai offers the same GPT models at lower rates with:

• Fingerprint-verified authentic models (not cheaper substitutes)
• No geographic restrictions—works without VPN
• Local payment methods for non-US users
• Real-time pricing dashboard

Check current OpenAI API prices on APIMaster →