Tokenizers split text into small pieces, not words.
11 tokens, 8 words

Free calculators for LLM costs and machine learning

Count tokens, compare API prices, size GPU memory, and explore the maths behind regression, PCA and neural networks. We built these for our own work first, and now they are free for everyone.

Count tokensCompare API costs

LLM tokens and costs

Know what a prompt costs before you send it.

Token CounterPaste text and see the token count, a colored token view, and the cost on each model.Token Cost CalculatorEnter one request size and compare OpenAI, Claude, Gemini, DeepSeek, Grok and Perplexity, with a monthly forecast.Tokens to WordsTurn a token budget into a rough word count, and the reverse.Token Speed SimulatorSee how tokens per second changes real generation time.LLM Memory (VRAM) CalculatorSize the GPU memory needed to run or fine-tune a model yourself.

Machine learning and statistics

Interactive calculators you can change and watch respond.

Activation Function VisualizerPlot ReLU, sigmoid, tanh and others, with their derivatives.Bayes Theorem CalculatorUpdate a probability from prior, likelihood and evidence.Confusion Matrix CalculatorGet precision, recall, F1 and accuracy from your counts.Gradient Descent VisualizerWatch learning rate and steps move a point down a loss curve.Linear Regression CalculatorFit a line to your data and read slope, intercept and R².Logistic Regression CalculatorClassify two outcomes and see the decision boundary.Multinomial Logistic RegressionClassify three or more outcomes with softmax probabilities.Matrix Multiplication CalculatorMultiply matrices step by step.Neural Network CalculatorTrain a small network online and follow it step by step.NN Parameter and FLOPs CounterCount the parameters and compute cost of a network design.PCA CalculatorReduce dimensions and see the variance each component keeps.