Claude vs GPT vs Gemini: Coding Costs in 15 Minutes
The cheapest coding model is not necessarily the one with the lowest token price. Repository context, generated patches, failed attempts and repeated tool calls all affect your bill. This quick-start guide shows how to compare Claude, GPT and Gemini using the number that matters: cost per successfully completed coding task.
1. Compare equivalent routes, not brand names
Each family includes models with different prices and capabilities. Start with one candidate per family rather than treating every Claude, GPT or Gemini model as interchangeable. Claude Sonnet 5.5 and Gemini 3.1 Pro are two concrete candidates available through 59API; choose a current GPT option from the same catalog.
Record each exact model, its input and output rates, the billing currency and any applicable caching or long-context charges. Compare either direct-provider prices or relay prices consistently. A provider's published rate is not automatically the rate charged by a relay.
- Claude: Measure how much repository context and how many revision rounds your chosen route needs.
- GPT: Include agent loops, tool-result tokens and any separately billed token categories shown in its pricing documentation.
- Gemini: Check whether your workload crosses a context-length pricing threshold and whether caching changes the effective rate.
These checks are not claims that one family always uses more tokens. They identify variables to verify on the specific routes you select.
2. Calculate a comparable coding request
Use this baseline formula when rates are quoted per million tokens: request cost = input tokens × input rate ÷ 1,000,000 + output tokens × output rate ÷ 1,000,000. Account separately for cached tokens or other billing categories when applicable.
Here is an illustrative calculation, not current vendor or 59API pricing. Suppose a coding task uses 20,000 input tokens and 4,000 output tokens:
- Hypothetical Claude route: $3 input and $15 output per million tokens produces a $0.120 request.
- Hypothetical GPT route: $2 input and $8 output produces a $0.072 request.
- Hypothetical Gemini route: $1 input and $4 output produces a $0.036 request.
Replace those assumptions with live quotes before making a purchasing decision. The example demonstrates the calculation, not a real-world price ranking. It also shows why output pricing matters: a long explanation accompanying every patch can materially increase spending.
3. Run a small, retry-aware benchmark
Choose five tasks from your actual backlog: a bug fix, a unit-test addition, a refactor, a dependency update and a repository-navigation question. Give each candidate the same starting files, instructions, tool permissions and acceptance criteria.
- Start each run from the same clean repository revision.
- Set identical limits for attempts, elapsed time and spending.
- Record total billed cost across every request, including failed attempts.
- Run tests and inspect the diff; plausible-looking code is not a passing result.
- Calculate total benchmark spend ÷ accepted tasks, and record review time separately.
Retries can reverse the apparent ranking. Using the hypothetical numbers above, four $0.036 attempts cost $0.144, exceeding one successful $0.120 attempt. Report success rate alongside cost so an inexpensive route does not win by leaving difficult tasks unfinished.
4. Test all three through one low-cost integration
59API provides inexpensive, pay-as-you-go access to Claude, GPT, Gemini and other families through an API relay. It offers native, official-quality models without downgrading, making it a useful low-cost option for running this comparison without separate provider integrations.
Its API base URL is https://api.59api.com. Create an API key, store it in an environment variable or secret manager, and follow the documented configuration for your tool. 59API supports Claude Code, Codex, Gemini CLI and OpenAI SDKs. Copy exact model identifiers and endpoint paths from its documentation rather than guessing them.
5. Keep the cheapest successful workflow
Route routine edits to the lowest-cost candidate that passes your checks, and escalate difficult failures to a stronger performer. Trim irrelevant context and request concise patches. Recheck prices periodically. If you want a convenient starting point, sign up for 59API and benchmark a small prepaid budget; its referral rebate can provide additional savings, subject to current terms.