ModelFusion is a toolkit aimed at people who work with many large language models at once and want to make better cost and capability decisions. Its core is a set of free, browser-based utilities: an LLM cost calculator that estimates API spend across providers, a prompt tokenizer for counting tokens and trimming prompt length, a model selector quiz, a benchmark comparator using metrics like MMLU and HumanEval, a local LLM runner guide for Ollama and LM Studio, an open-source model directory and a glossary of AI terms.
Beyond the calculators, ModelFusion also markets a product layer: MultiChat for comparing responses from multiple models side by side, document projects for chatting with uploaded PDFs and Word files, a unified API that presents one interface across providers, and usage analytics for tracking cost and performance. The site positions these as suitable for research, business, development and education audiences.
Much of the toolkit is completely free and needs no registration, with the latest model pricing and benchmark data refreshed regularly. Because the underlying costs it reports come from third-party providers, users should still confirm current rates with OpenAI, Anthropic, Google or whichever vendor they rely on, as provider pricing changes often.
