OpenAI API Monthly Cost Calculator: GPT-4o, mini & o3
Estimate your monthly OpenAI API bill instantly. Enter model, tokens per request, and daily volume — see cost per day, Batch API 50% savings, and side-by-side comparison with Claude and Gemini.
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Data updated: · Source: OpenAI API Pricing
Reviewed by: Martín Rodríguez (editorial policy ) · Last reviewed:
Result
Cost per Day
Estimated Monthly Cost
Monthly Input Token Cost
Monthly Output Token Cost
Batch API Savings vs Standard
Total Tokens per Month
vs. Claude & Gemini (same workload)
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Your result
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API costs spiral fast without a clear estimate. This calculator gives you an exact monthly OpenAI API bill based on your model, average tokens per request, and daily request volume. It applies the real 2026 pricing, shows the 50% Batch API discount impact, and compares your cost against Claude Sonnet and Gemini 2.5 Pro — so you can pick the right model before you see the invoice.
When to use this calculator
- Estimating monthly API budget before launching an AI-powered product
- Comparing cost impact of upgrading from GPT-4o-mini to GPT-4o or o3
- Calculating Batch API savings for offline or asynchronous workloads
- Projecting costs as daily request volume scales up over time
- Benchmarking OpenAI pricing against Claude Sonnet and Gemini 2.5 Pro
- Planning infrastructure spend for a SaaS product with embedded AI features
OpenAI API & Competitor Pricing — June 2026 ($/1M tokens)
| Provider & Model | Input ($/1M tokens) | Output ($/1M tokens) | Batch API (50% off input) | Batch API (50% off output) |
|---|---|---|---|---|
| OpenAI GPT-4o | $2.50 | $10.00 | $1.25 | $5.00 |
| OpenAI GPT-4o mini | $0.15 | $0.60 | $0.075 | $0.30 |
| OpenAI o3 | $2.00 | $8.00 | $1.00 | $4.00 |
| Anthropic Claude Sonnet | $3.00 | $15.00 | — | — |
| Google Gemini 2.5 Pro (≤200K ctx) | $1.25 | $10.00 | — | — |
Fuente: OpenAI, Anthropic, Google DeepMind (2026). Batch API discount (50%) applies only to OpenAI models for asynchronous requests. Competitor models do not offer Batch API pricing via this calculator.
How it works
OpenAI API Pricing in 2026
OpenAI charges per token — roughly 4 characters per token in English. Pricing varies by model and is billed separately for input (your prompt + context) and output (the model's completion). The Batch API cuts all rates by 50% for non-urgent, asynchronous requests.
Pricing Table (June 2026)
| Model | Input ($/1M tokens) | Output ($/1M tokens) | Best for |
|---|---|---|---|
| GPT-4o | $2.50 | $10.00 | General tasks, vision, function calling |
| GPT-4o mini | $0.15 | $0.60 | High-volume, cost-sensitive workloads |
| o3 | $2.00 | $8.00 | Complex reasoning, coding, math |
Cost Formula
daily_input_cost = (input_tokens × requests_per_day / 1,000,000) × input_price
daily_output_cost = (output_tokens × requests_per_day / 1,000,000) × output_price
cost_per_day = (daily_input_cost + daily_output_cost) × discount_factor
cost_per_month = cost_per_day × 30.44discount_factor = 0.50 with Batch API, 1.0 otherwise. One month = 30.44 days (Gregorian average).
Worked Example
Model: GPT-4o, 500 input + 500 output tokens, 1,000 requests/day, no Batch API:
daily_input = (500 × 1,000 / 1,000,000) × $2.50 = $1.25
daily_output = (500 × 1,000 / 1,000,000) × $10.00 = $5.00
cost_per_day = $1.25 + $5.00 = $6.25
cost_per_month = $6.25 × 30.44 ≈ $190.25With Batch API enabled: $3.125/day → $95.13/month.
Common Workloads: Cost Reference
| Workload | Tokens (in/out) | Req/day | GPT-4o/mo | GPT-4o-mini/mo |
|---|---|---|---|---|
| Simple classifier | 200 / 50 | 5,000 | ~$152 | ~$9 |
| Chatbot turn | 500 / 300 | 2,000 | ~$259 | ~$16 |
| RAG answer | 2,000 / 500 | 500 | ~$152 | ~$9 |
| Long-form summary | 4,000 / 800 | 100 | ~$55 | ~$3 |
| Code review | 1,500 / 1,000 | 200 | ~$84 | ~$5 |
Competitor Comparison (same workload, June 2026)
| Provider & Model | Input ($/1M) | Output ($/1M) |
|---|---|---|
| OpenAI GPT-4o | $2.50 | $10.00 |
| OpenAI GPT-4o mini | $0.15 | $0.60 |
| OpenAI o3 | $2.00 | $8.00 |
| Anthropic Claude Sonnet | $3.00 | $15.00 |
| Google Gemini 2.5 Pro (≤200K) | $1.25 | $10.00 |
Limitations
Frequently asked questions
What does GPT-4o actually cost per request?
At the June 2026 public rates, GPT-4o costs $2.50 per 1M input tokens and $10.00 per 1M output tokens. A typical chatbot turn with 500 input + 300 output tokens costs about $0.00125 + $0.003 = $0.00425 per request — or $4.25 for 1,000 requests. GPT-4o-mini ($0.15/$0.60) cuts that to ~$0.255 for the same 1,000 requests.
How does the OpenAI Batch API work and when should I use it?
The Batch API lets you submit a JSONL file of requests processed asynchronously within 24 hours. In exchange, every input and output token costs 50% less. It's ideal for data annotation, content generation pipelines, evals, embeddings, and any use case where you don't need a real-time response. Not suitable for user-facing chatbots or real-time features.
How is o3 priced compared to GPT-4o in 2026?
o3 costs $2.00/M input and $8.00/M output — very close to GPT-4o ($2.50/$10.00) after its 2025–2026 price cuts. o3 is optimized for complex reasoning tasks (code, math, multi-step logic) and often produces better results on those tasks, making it competitive in cost-per-accuracy terms despite the slightly different rates.
What is a token and how do I estimate how many I use?
A token is roughly 4 characters or ¾ of a word in English. The phrase 'OpenAI charges per token' is about 6 tokens. A 500-word blog post is roughly 650–700 tokens. For exact counts, use OpenAI's open-source tiktoken library or the Tokenizer tool in the OpenAI Playground.
Does this calculator include image, audio, or embedding costs?
No. This calculator covers text tokens only. Vision inputs are priced per image based on detail level. Audio via Whisper or TTS is priced per minute. Embeddings use a separate per-token rate. Enter 0 for output tokens if you only use the Embeddings API.
How accurate is the monthly estimate?
It assumes uniform daily usage multiplied by 30.44 days. Real traffic has weekday/weekend variation. Treat this as a planning estimate for budgeting — your actual invoice will differ due to prompt caching, retries, and any enterprise tier pricing. Check your Usage dashboard at platform.openai.com for live spend.
Is GPT-4o-mini good enough to replace GPT-4o for most apps?
For the vast majority of structured tasks — classification, extraction, summarization, simple Q&A — GPT-4o-mini delivers near-identical results at ~6% of GPT-4o's cost. The quality gap widens mainly on complex multi-step reasoning, nuanced writing, and tasks requiring strong instruction-following on ambiguous prompts.
Does OpenAI offer Prompt Caching and how does it affect cost?
Yes. For prompts longer than 1,024 tokens, OpenAI automatically caches the repeated prefix across API calls. Cached input tokens cost 50% less than standard input tokens. This is highly effective for RAG pipelines with a large, stable system prompt — you only pay full price for the first call, then half-price for subsequent calls with the same prefix.
How does OpenAI pricing compare to Claude and Gemini in 2026?
For a typical text workload in June 2026: Gemini 2.5 Pro is $1.25/$10.00 per 1M tokens (cheapest input); GPT-4o is $2.50/$10.00; Claude Sonnet is $3.00/$15.00. GPT-4o-mini at $0.15/$0.60 is the cheapest of all four for high-volume, lower-complexity workloads. o3 at $2.00/$8.00 is competitive for reasoning-heavy tasks.
What if my prompt changes every request (no caching opportunity)?
Then you pay the full standard rate for every input token. To reduce costs, focus on keeping system prompts concise, avoid sending unnecessary context, use GPT-4o-mini for initial filtering or routing, and reserve GPT-4o or o3 only for requests that truly need their capabilities.
Sources & references
- OpenAI API Pricing — OpenAI (2026)
- OpenAI Batch API Documentation — OpenAI (2026)
- Anthropic Claude API Pricing — Anthropic (2026)
- Google Gemini API Pricing — Google DeepMind (2026)
- OpenAI Tokenizer (tiktoken) — OpenAI (2026)
Methodology & trust
Editorial
Calculadora de tecnología revisada por el equipo editorial de Hacé Cuentas, contrastada con OpenAI API Pricing, según nuestra política editorial y metodología.
Updates
Última revisión: June 20, 2026. Los parámetros se verifican periódicamente con las fuentes citadas.
Privacy
Calculations run 100% in your browser. We do not store or transmit your data.
Limitations
Indicative results. For critical decisions, consult a professional.
📌 How to cite this calculator
Rodríguez, M. (2026). OpenAI API Monthly Cost Calculator: GPT-4o, mini & o3. Hacé Cuentas. https://hacecuentas.com/openai-api-monthly-cost-estimator
Contenido bajo licencia CC-BY 4.0 — reutilizable citando la fuente con enlace a Hacé Cuentas.