Screening tools. None of these is a substitute for professional judgement. Every tool here is a first-pass aid, built and maintained by one person, and none of it is certified, validated or independently reviewed software. Each tool carries its own scope limits; this is what applies to all of them. Open for the full notice.
What these are
Browser-side calculators, converters and reference tables. They run locally, they cost nothing, and they are built to be open about their method and their sources rather than authoritative about their answers. Several show their working, cite what they were checked against, and say plainly where a check was not performed.
What none of them is
- A design, clinical, safety or compliance tool.
- A substitute for a licensed professional, the governing standard or code, a manufacturer's data, a product label, or a measurement.
- Validated software. Nothing here has been through independent verification, qualification, or a quality system.
- Complete. A tool that reports no problem has usually not checked for every problem, and several say so explicitly.
Status labels in the catalog are literal. Under Review, Prototypical and Experimental mean the tool has not finished being checked.
Never use anything here for
- Safety-critical, life-safety or life-support decisions, or any protective or safety instrumented function.
- Clinical diagnosis, treatment, or dosing for any person or animal.
- Relief, blowdown, overpressure or emergency-system sizing.
- Structural, electrical or pressure work that a person could be hurt by.
- Regulatory submissions, certification, or anything requiring a professional stamp.
- Legal, forensic, employment, academic-integrity or financial determinations about another person.
Before you act on any number here
Check it against the governing standard, the manufacturer's data, the datasheet or the label. Reproduce it by an independent method. Have a qualified professional review it. A result that agrees with what you expected is not verification.
Engineering Calculators
-- toolsSimple Unit Converter
Convert between metric, imperial, and engineering units with precision.
Ohm's Law Calculator
Calculate voltage, current, resistance, and power relationships.
Linear Thermal Expansion
Calculate material expansion and contraction due to temperature changes.
Visual Integration Tool
Interactive numerical integration (Area Under Curve) using the trapezoidal rule.
Graph Paper Generator
Generate printable graph paper PDFs with cartesian, dot, boxed, and XY-axis templates.
ESP32 Pinouts
Reference diagrams for ESP32 development board pin configurations.
Raspberry Pi Pinouts
GPIO reference diagrams for Raspberry Pi board configurations.
Sensors Reference
Common sensors for temperature, pressure, flow, proximity, vibration, and more.
Battery Capacity Calculator
Calculate how long a battery will last based on its capacity and device power consumption.
Beam Deflection Calculator
Deflection, bending moment, and support reactions for cantilever, simply supported, fixed-fixed, and propped beams, with the boundary condition picked from its own diagram.
Control Valve Sizing
Flow coefficient to the ISA-75.01.01 procedure for liquid and gas service, with the choked flow, cavitation and flashing checks the one-line formula leaves out.
Uncertainty Propagation Calculator
Propagate measurement error through an arbitrary formula via symbolic partial derivatives (first-order Taylor), with a foldable steps panel, per-variable contribution breakdown, and a Monte Carlo cross-check.
Steam Tables Lookup
Lookup water and steam properties from vendored saturation, compressed-liquid, superheated, and supercritical tables.
PID Playground
FOPDT process with parallel-form PID controller, exact zero-order-hold, fractional dead time, derivative filtering, anti-windup, and Ziegler-Nichols / Cohen-Coon / AMIGO / lambda tuning rules.
Psychrometric Calculator
Calculate moist air properties (Tdb, Twb, Tdp, RH, humidity ratio, enthalpy, specific volume) using ASHRAE equations with interactive psychrometric chart.
IT & Coding Tools
-- toolsColor Picker & Converter
Pick colors and convert between HEX, RGB, HSL, and other formats.
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal.
JSON Formatter
Format, validate, and minify JSON data with syntax highlighting.
Excel Formula Extractor
Extract workbook formulas, defined names, hidden sheets, and external workbook references locally from Excel files.
Regex Tester
Test and debug regular expressions with live matching and explanation.
Markdown Preview
Write and preview Markdown with Markdown, CommonMark, and Github modes. Export to HTML, download files, and manage local images.
Markdown Exporter
Standalone Markdown editor with live side-by-side preview and direct export to PDF or DOCX.
PDF Diff Checker
Compare multi-page PDFs with semantic text diffing, in-place highlighting, change navigation, and a visual pixel diff. Word or character granularity, ignore-case and page-break options, TXT/JSON reports.
Database Tools
-- toolsDuckDB Playground
A browser-based SQL playground powered by DuckDB-WASM. Execute SQL queries against imported data files entirely client-side with no server dependencies.
SQLite Viewer
Browser-based SQLite database viewer using sql.js WASM. Browse tables, view schemas, execute queries, and export results, all client-side with no server uploads.
CSV Profiler
Inspect CSV and TSV files locally in the browser. Infer column types, flag sparse or inconsistent data, preview rows, and generate schema exports without uploading anything.
Parquet Viewer
Inspect Apache Parquet files locally: schema, row-group and per-column compression stats, footer statistics, and a paginated data preview. No uploads, all in the browser.
General Utilities
-- toolsMeeting Planner
Share a link, mark when you're free. Availability heatmap with no accounts, no tracking, no ads.
Timestamp Converter
Convert between Unix timestamps, ISO dates, and human-readable formats.
Crypto Lab
Encrypt and decrypt via AES/DES, or generate MD5/SHA hashes.
Word Count
Count words, characters, sentences, and paragraphs in your text.
Case Conversion
Convert text between uppercase, lowercase, title case, and more.
Encoding / Decoding
Encode and decode Base64, URL, HTML entities, and other formats.
Productivity Timer
Focus timer for deep work sessions with automatic breaks, completion tracking, and adjustable alarm + notifications.
Workweek Planner
Generate printable daily planner sheets with configurable time blocks, date selection modes, combined layouts, and saved print plans.
Screenshot Tool
Capture a screen frame (or upload/paste), crop precisely with pan/zoom + optional aspect lock, then export PNG/JPEG/WebP or copy to clipboard(all local).
Biochemical Engineering Utilities
-- toolsHED Calculator
Translate preclinical animal doses to Human Equivalent Doses (HED) via BSA normalization.
Toxicology Body Burden
Estimate total systemic load from plasma concentration using volume of distribution models with optional kinetic back-calculation.
Oral Multi-Dose Simulator
Simulate oral dosing regimens (single or repeated) with first-order absorption and elimination to visualize concentration-time profiles and key PK metrics.
Creatine Lab
Estimate how much creatine dissolves, how storage changes it, and how daily use changes a rough body-pool estimate.
Seed Storage Lab
Look up seeds per ounce and pound, count your own sample, and estimate how long orthodox seed keeps at a given temperature and moisture.
Hormone Research Reference
Browse source-linked hormone reference rows, cycle profiles, production estimates, assay notes, and citation details. Experimental reference only; not for medical interpretation.
Yogurt CFU/g Estimator
Explore literature-anchored yogurt starter counts, pH trajectory, refrigerated CFU retention, and coarse set proxies for classical St/Lb cultures.
Species Doubling Reference
Reference tool for bacterial doubling times in yogurt fermentation processes.
Stoichiometry Calculator
Advanced chemical formula parsing, automated equation balancing, and interactive mass-mole calculations.
Data Science
-- toolsScientific Graph Compare
Rapid paper-figure measurement for images and PDFs. Crop to ROI, place baseline and axis tick, compare control versus treatments, and export annotated PNG or CSV.
DBSCAN Visualizer
Interactive density-based clustering with Rust/WASM performance. Features 2D/3D visualization, step-through animation, k-distance plots, and validation against scikit-learn.
Linear Regression
Simple and multiple OLS regression with multicollinearity detection (VIF). Upload CSV/Excel data, paste from clipboard, or use built-in examples. Output includes coefficients, R², F-stat, p-values, 95% CI, residuals table, and interactive charts (scatter, Q-Q plot, residuals).
AI
-- toolsAI Image Detector - FFT Noise Freq Analysis
Inspect an image's frequency spectrum for periodic upsampling artifacts, with a grid prominence score. Rust/WASM FFT with JS fallback; a heuristic, not a verdict.
Face Blur
Privacy-focused face blurring using MediaPipe. Oval-shaped face regions from 468 landmarks, 7 blur modes, manual draw mode, and undo/redo support.
Token Throughput Visualizer
Visualize how a given tokens per second rate, startup delay, and output length feel in practice with a live offline stream preview.
Local LLM TCO Calculator
Calculate the Total Cost of Ownership (TCO) for local LLM inference vs commercial cloud APIs and plans.
Educational
-- toolsLamport Timestamps
Interactive learning tool for Lamport clocks and vector clocks. Explore causal ordering, message passing, and concurrency with visual process diagrams and event tracing.
Moody Chart Reader
Interactive Moody chart reader for pipe flow: drag to read Re vs Darcy fD, compute friction factor or infer ε/D, export PNG.