Claude API Pricing vs OpenAI API Pricing for Coding

Claude API pricing vs OpenAI API pricing has no single winner. OpenAI's GPT-5.6 Luna is much cheaper than Claude Haiku 4.5 at the low-cost end. In the balanced and frontier pairs, Claude Sonnet 5 and Opus 5 have lower standard output prices than GPT-5.6 Terra and Sol. Above 272K input tokens, OpenAI's long-context multiplier can widen the difference again.

Those statements compare direct API rate cards, not model quality. A cheaper model can cost more per accepted coding task when it needs retries, misses a constraint, or produces more output. Start with the workload, then compare billed tokens and completed results.

Claude API vs OpenAI API pricing at a glance

The direct rate card favors OpenAI for small, bounded work and gives Claude a modest output-price edge in the two closer coding tiers. That still does not make unlike models interchangeable.

Current standard token prices

The order below is input / cache read / output, in USD per million tokens.

Haiku and Luna are not equivalent simply because both occupy a low-cost row. The same applies to Sonnet and Terra or Opus and Sol. These are useful budget pairs because they target similar buying positions, not because a benchmark proved equal capability.

The live model catalog shows current OmniaKey quotes separately from direct provider rates. Check it again before setting a production budget.

Cache writes and cache hits are different charges

Both providers price a cache hit at one tenth of standard input, but cache creation differs.

For example, a 5-minute cache write costs $2.50 per million tokens on Sonnet 5 and Terra. A one-hour Sonnet write costs $4.00. Sol and Opus both charge $6.25 for their shorter cache write, while Opus charges $10.00 for a one-hour write.

Caching wins only when the stable prefix is reused enough times to repay the write. Measure cache-write tokens, cache-read tokens, and misses separately. A prompt that changes near the top on every turn may never realize the advertised read discount.

Batch and Flex pricing

Anthropic's Batch API discounts both input and output tokens by 50%. OpenAI's Batch table also halves input, cache, cache-write, and output rates for GPT-5.6. OpenAI currently displays the same token rates for Flex processing, which trades speed and availability for lower cost.

Batch is appropriate for evaluation sets, offline classification, bulk review, or other work that does not need an interactive response. It is not a direct replacement for a coding agent waiting on the next tool call.

Provider-hosted tools can add separate charges. Web search, code execution, or another managed tool must be budgeted in addition to model tokens when the selected API surface bills for it.

OpenAI also adds a 10% uplift to regional-processing data-residency endpoints for eligible models released on or after March 5, 2026. The tables above use standard global rates; apply that premium before comparing a residency-bound workload.

Long context changes the comparison

Anthropic says Claude 4.6 and later use standard token rates across the full native 1M context window. A 900K-token request uses the same per-token rate as a 9K-token request, although the larger request still contains far more billable tokens.

OpenAI's GPT-5.6 rate card has separate long-context columns. When input exceeds 272K, the higher prices apply to the entire request:

• input and cached input become 2x the short-context rate;
• cache writes become 2x their short-context rate;
• output becomes 1.5x the short-context rate.

For Terra, that means $4 input and $18 output per million tokens. For Sol, it means $10 input and $45 output. Luna becomes $0.40 input and $1.80 output.

This is why a "1M context" badge is not a cost estimate. Retrieval, compaction, and a focused evidence set often save more than switching providers.

What a short coding task costs

Assume one uncached request uses 100,000 input tokens and 20,000 output tokens. Exclude tools, retries, regional premiums, and gateway pricing.

The arithmetic is reproducible:

cost = input_millions x input_rate
     + output_millions x output_rate

Luna's gap is large. The balanced and frontier gaps are small enough that one retry, a longer response, or a different tokenizer can reverse the result.

What repeated cached work costs

Now assume the same 100,000 input tokens are a warm cache hit and output remains 20,000 tokens. Do not include the earlier cache-write charge.

The relative answer is similar because both providers discount cache reads by 90%. Real savings depend on prefix stability and the number of successful reuses.

A 300K-input task tells a different story

Consider 300,000 uncached input tokens and 40,000 output tokens. This crosses OpenAI's 272K threshold but remains inside the native Claude 5 context window.

This does not prove Claude is the better long-context model. It proves that the same reported token counts have different direct-provider costs under current rules. Model quality, tokenization, retrieval, and accepted-task rate still matter.

Current OmniaKey prices are a separate route

OmniaKey exposes both model families under one prepaid balance. The current catalog quote is not the direct Anthropic or OpenAI price and can change independently.

These gateway prices currently favor GPT across all three pairs. That is a route comparison, not a claim that one provider's direct list price changed. Use the live catalog and your usage ledger rather than copying this table into a permanent budget.

The balance and usage guide explains how to inspect spend. The Claude Code pricing guide owns the separate subscription-versus-API decision.

Choose by workload, not provider logo

Start with Luna when the task is narrow, repeatable, cheap to verify, and high volume. Its direct rate is the clearest price winner in this comparison.

Start with Sonnet or Terra for daily repository work. Direct short-context prices are close, so protocol fit and accepted-task cost matter more than four cents in the example. The Sonnet 5 vs Terra comparison owns that model decision.

Start with Opus or Sol when ambiguity and the cost of a wrong answer justify a frontier model. Opus has the lower direct output price; Sol fits OpenAI Responses and Codex-native workflows. Use the Opus 5 vs Sol comparison for the capability boundary.

For a wider provider and model-family view, use the coding-model guide. This page stays focused on price mechanics.

Compare completed-task cost

Token cost is only one term:

completed-task cost = accepted run
                    + failed attempts and retries
                    + provider-hosted tool charges
                    + developer correction time

Record model ID, protocol, effort, input, cache write, cache read, output, tool calls, retries, elapsed time, and the acceptance result. Compare the same repository commit and the same test command. Without that control, a cheap transcript can hide an expensive failed task.

Final verdict

OpenAI API is cheaper at the low-cost coding tier because GPT-5.6 Luna is priced far below Claude Haiku 4.5. Claude API has lower standard output prices in the matched Sonnet/Terra and Opus/Sol pairs. Claude's current long-context rule is also simpler, while OpenAI's full-request multiplier above 272K can materially increase a large task.

There is no universal cheaper provider. Match models by workload, include cache writes and tools, then measure accepted-task cost on the route you will actually buy.

Frequently asked questions

Is Claude API or OpenAI API cheaper?

It depends on the model tier and workload. GPT-5.6 Luna is much cheaper than Haiku 4.5. Sonnet 5 and Opus 5 have lower standard output rates than Terra and Sol, while input prices tie in those two pairs.

What is the main difference between Claude and OpenAI API pricing?

Claude offers 5-minute and 1-hour cache-write prices and keeps standard rates across Claude 4.6+ native 1M context. OpenAI uses one cache-write rate and raises the full GPT-5.6 request price above 272K input. Both offer 90% cache-read discounts and 50% batch rates.

Which API is cheaper for long context?

At identical reported token counts above 272K, current direct rates favor Claude Sonnet 5 or Opus 5 over Terra or Sol. Tokenizers and model results differ, so verify with billed usage rather than character count.

Are Claude and ChatGPT subscriptions included in these prices?

No. These are developer API token rates. Claude and ChatGPT subscriptions have separate allowances and terms. Do not compare a monthly plan directly with one million API tokens.

Can one API key access both Claude and GPT models?

An OmniaKey account can access supported Claude and GPT models under one prepaid balance, using the documented Anthropic-compatible or OpenAI-compatible route. The requested model and protocol still remain explicit.

Do Batch discounts work for interactive coding agents?

Usually not as a drop-in replacement. Batch is asynchronous and fits offline work. Interactive agents need the next response to continue tool use, so standard or another synchronous service tier is normally the relevant comparison.

Sources checked

• Anthropic API pricing
• OpenAI API pricing
• OpenAI GPT-5.6 Sol
• OpenAI GPT-5.6 Terra
• OpenAI GPT-5.6 Luna
• Anthropic model overview

Information was verified August 16, 2026. Provider rates, regional premiums, service tiers, tool charges, and gateway quotes can change. Check both official pricing pages and the live catalog before production use.