Developer Tools

Add Linear, Conv2d, Embedding, MultiheadAttention, LayerNorm, and BatchNorm2d layers and instantly see total parameters, float32/float16/int8 memory estimates, and a comparison against BERT, GPT-2, and ResNet-50.

Plot LR over epochs for Cosine Annealing, Step Decay, Linear Warmup + Cosine Decay, Exponential Decay, and ReduceLROnPlateau. Copy the PyTorch scheduler code for any configuration.

Compute precision, recall, F1, F2, accuracy, specificity, MCC, and NPV from TP/TN/FP/FN values. Includes scikit-learn code.

Paste a list of numbers and instantly get mean, median, mode, std dev, variance, IQR, skewness, and more. Includes NumPy and Pandas snippets.

Multiply two matrices up to 6×6 with step-by-step results. Understand the shapes behind neural network layers. Includes NumPy and PyTorch code.

Estimate GPU memory needed for inference or training given parameter count and precision. Rule-of-thumb estimates, not exact figures.

Calculate cosine similarity, dot product, and Euclidean distance between two vectors. For comparing embeddings.

Get a heuristic score of AI-style writing patterns in a text. Not a calibrated probability and not a detector of specific models. Free, 5 checks per day with a Google account.

Estimate tokens for GPT-4o, Claude, and Llama from any text. Shows context window usage, estimated API cost, and includes Python tiktoken snippets.

Compare estimated API cost across GPT-4o, Claude, and Gemini for a given number of input and output tokens. Dated pricing snapshot.

Generate a word cloud from any text. Visualize term frequency and explore NLP preprocessing.

Convert HEX color codes to RGB and RGB to HEX instantly. Also shows HSL values, a live color preview, and CSS snippets. Includes a color picker and 12 common web colors.

Generate strong, cryptographically secure random passwords. Choose length (8–64) and character sets. 100% client-side — your password never leaves your browser.

Generate RFC 4122 version 4 UUIDs (GUIDs), one at a time or in bulk (up to 100). Optional no-dashes and uppercase formatting. 100% client-side.

Generate placeholder Lorem Ipsum text by paragraph count, optionally starting with the classic opening line. 100% client-side.

Write Markdown and see the rendered HTML preview live, side by side. 100% client-side.

Remove unneeded line breaks from text: rejoin hard-wrapped lines into paragraphs, collapse extra blank lines, or strip all line breaks into one line. 100% client-side.

Turn any text or URL into a scannable QR code, with adjustable error correction, downloadable as SVG. 100% client-side.

Test and debug regular expressions in real time with match highlighting. Supports global, case-insensitive, multiline, and dotAll flags. Includes Python re snippets.

Format and beautify SQL queries instantly. Uppercases keywords, puts each clause on its own line, and indents columns and conditions.

Convert CSV to JSON and JSON to CSV in your browser. Handles quoted fields, nested values, and automatic type coercion. Includes Pandas snippets.

Validate, format, and convert YAML files online. Supports YAML → JSON and JSON → YAML. Includes PyYAML Python code snippets.

Encode text to Base64 or decode Base64 strings instantly. UTF-8 safe. 100% client-side — nothing leaves your browser. Includes Python and JS snippets.

Convert strings between camelCase, PascalCase, snake_case, kebab-case, SCREAMING_SNAKE_CASE, Title Case, and more. Instant copy for each variant.

Pretty-print, validate, and minify JSON instantly. 100% client-side — your data never leaves the browser. Includes Python and JS code snippets.

Compare two text files or code blocks side-by-side with GitHub-style red/green highlighting. Generate a shareable diff link for teammates.

Build a cron expression from plain English dropdowns, or paste any expression to translate it to a human-readable schedule. Includes a full cron cheat sheet.

Convert between Unix timestamps and human-readable dates. Includes Python, JavaScript, Pandas, and SQL snippets.

Paste a JWT to decode its header and payload instantly, with expiry status. 100% client-side. Decode only, does not verify the signature.

Type randomly generated key sequences, not memorized words, and see live WPM and accuracy plus a color-coded histogram of exactly which keys you mistype most.

Learn German by reading a free graded A1 story (Lena in Leipzig), Grimm fairy tales and Kafka's Die Verwandlung: pick the missing word from 3 choices, with translations and grammar explanations. Free, no signup.

Estimate monthly payments, total cost, and total interest for a fixed-rate amortizing loan.

Open up to three finance calculators side by side and see how one scenario plays out across all of them at once.

Project investments, debt, and net balance through retirement using adjustable savings and capital assumptions.

See how a lump sum grows over time with compound interest. Compare annual, monthly, and daily compounding frequency.

Compare the debt snowball (smallest balance first) and debt avalanche (highest interest first) methods side by side.

Find your target emergency fund size based on months of essential expenses, and how long it will take to reach it.

Split your net income into needs, wants, and savings targets, then compare against your actual spending.

Itemize your assets and liabilities to find your total net worth, with a reference table for typical net worth by age.

Rule of 72 doubling-time estimates, plus a goal-based calculator for how long it takes to reach a savings target.

Find the hourly rate you need to charge as a freelancer or contractor to hit a target income, after overhead, time off, and profit margin.

See how long a single card takes to pay off at the minimum payment versus a higher fixed payment, and how much extra interest the minimum payment costs.

Calculate net present value from a discount rate and future cash flows, or simple future value of a lump sum.

Estimate future cost or lost purchasing power using an assumed average annual inflation rate. Not official CPI data.

Calculate Body Mass Index and its screening category in metric or imperial units, with limitations explained.

Estimate your one-rep max from any weight and rep count using the Epley and Brzycki formulas, plus a training percentage table.

Split a daily calorie target into protein, carb, and fat grams using common macro ratios.

Find what % of a number is, calculate percentage increase or decrease, add or subtract a percentage, and more. Five calculators in one — instant results.

Find what day number any date falls on (1–366), or convert a day number back to a calendar date. Handles leap years automatically.

Find the day number of any date, track how much of the year has elapsed, or calculate how many years ago a given year was.

Browse countdowns for Christmas, New Year, Halloween, Thanksgiving, Easter, and other major holidays from 2025 through 2030.