LLM Speed Simulator
A tool for visualizing LLM token-generation speeds.
Controls output rate after the response starts.
Adds variability between tokens to imitate uneven pacing.
Stream
No prompt is sent to an AI model. No account is required. The simulator runs in your browser.
What is a token?
A token is the unit a language model processes and generates. One token can be a whole word, part of a word, punctuation, or whitespace. In English, a useful rough estimate is that 1 token is about 4 characters, 30 tokens is about 1-2 sentences, and 100 tokens is about 75 words.
Why TPS alone is not enough
A response feels fast or slow because of three things: how long it takes before the first token appears, how quickly tokens arrive after that, and how long the answer is. Streaming lets people begin reading earlier, but it does not make a long answer short.
What this simulator shows
This tool focuses on output pacing after an answer starts. Change the TPS rate, add jitter, and toggle paragraph formatting to see how speed, variability, and presentation change the feeling of waiting.
Why you may want to use it
Use TPS Simulator when you want to make AI response speed easier to understand. You can compare what 10 TPS versus 40 TPS feels like before choosing a model, designing a chat interface, or explaining latency to someone who does not work with model metrics every day.
It is also useful when a number on a benchmark chart is too abstract. Watching text arrive makes it easier to see why technically correct and feels fast are not the same thing. A system may produce the right answer, but if the first visible token arrives late or the output is long, the experience can still feel slow.
What real systems add
Real deployments are affected by more than one steady TPS number. Model choice, prompt size, generated output length, queuing, concurrency, caching, and system load can all change perceived speed. Longer prompts often increase time to first token, and longer outputs often dominate the total wait.
What this tool does not do
TPS Simulator is a pacing simulator, not a benchmark. It does not call a live model, test quality, measure provider latency, or compare vendors. It answers a narrower question: if text starts now and arrives at this rate, how fast does that experience feel?
FAQ
What is TPS?
TPS means tokens per second: how many output tokens a system generates each second. It is useful, but it does not describe the full user experience on its own.
Is TPS the same as words per second?
No. Tokens can be full words, word fragments, punctuation, or spaces. The same TPS can reveal different amounts of visible text depending on the language and content.
Does streaming make a model faster?
Usually not in total completion time. Streaming improves perceived responsiveness because people can begin reading while the rest of the answer is still being generated.
Why can the same TPS feel different?
Answer length, time to first token, formatting, and tokenization all change the feel. A short answer can feel quick at modest TPS, while a long answer can feel slow at the same speed.
What does jitter simulate?
Jitter is a simplified stand-in for uneven pacing. Real streams can vary because of prompt size, system load, queuing, concurrency, and network conditions.
When is streaming worth it?
Streaming is most valuable when answers are long enough that a blocking interface would leave people staring at a spinner for several seconds.