How to Compare LLM Models Side by Side

A practical guide to evaluating GPT, Claude, Gemini, and other large language models with repeatable, data-driven comparisons.

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Define your evaluation criteria

Start by listing the dimensions that matter for your use case: output quality, latency, cost per token, context-window size, and instruction-following accuracy. Weight each criterion so you can score models objectively rather than relying on anecdotal impressions.

Select models to compare

Choose at least three models that span different providers and price tiers. For example, pair a frontier model like GPT-5.2 against a cost-efficient option like DeepSeek V3 and a balanced choice like Claude Sonnet 4.5. LLMWise gives you access to nine models through a single API, making selection painless.

Run controlled, identical prompts

Send the same prompts to every model under identical settings (temperature, max tokens, system prompt). Use LLMWise Compare mode to run prompts against multiple models in parallel and collect structured output in a single request, eliminating the need to juggle separate API keys and SDKs.

Analyze metrics and outputs

Review latency, time-to-first-token, token throughput, and total cost alongside qualitative output quality. Look for patterns: one model may excel at code while another handles creative writing better. LLMWise logs every request with these metrics automatically so you can query historical data.

Iterate and refine your model strategy

Use the results to build a routing strategy: assign the best model per task category and set up fallback chains for reliability. Re-run comparisons periodically as providers release updates. LLMWise Optimization policies can automate this cycle by analyzing your request history and recommending model changes.

Key takeaways

✓Always compare models on identical prompts and settings to get apples-to-apples results.

✓LLMWise Compare mode lets you test up to nine models in parallel through a single API call.

✓Revisit comparisons regularly, because model performance and pricing change with every provider update.

Common questions

How many models should I compare at once?

Start with three to five models that span different price and quality tiers. Comparing too many at once creates noise. LLMWise lets you test up to nine models in a single Compare request, so you can start broad and narrow down quickly.

Do I need separate API keys for each provider?

Not if you use a multi-model platform. LLMWise provides access to GPT-5.2, Claude Sonnet 4.5, Gemini 3 Flash, and six more models through one API key and one unified endpoint. You can also bring your own keys for direct provider routing.

Try it yourself

500 free credits. One API key. Nine models. No credit card required.

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