Expert tools for real-world systems and decisions
A working reference platform for electrical work, building and materials, unit conversion, math, and finance — over a thousand tools, formulas, tables, and datasets, each showing its method, units, and the standard it cites.
Browse by domain
One platform, built domain by domain
Each domain pairs working tools with the reference material behind them — standards, assumptions, units, and worked examples — so a number you take away is a number you can defend.
The toolkit underneath
Every domain draws on the same core surfaces. Open one directly, or jump into a proven starting point.
Featured workflows
Start from the decision, not the tool
Common professional workflows, each landing on a worked example with its inputs and assumptions in the open.
Electrical sizing
Wire-gauge selection with NEC ampacity and voltage-drop checks, from branch circuits to EV charging.
Material properties
Volume-to-weight decisions for concrete, metals, and fuels — with the density assumptions stated.
Body metrics
BMI, BMR, and body-fat estimation with the formula, its population limits, and disclaimers on the page.
Everyday & reference math
Percentage, tip, and geometry math, plus derivations and lookup tables you can cite.
Why the numbers hold up
Auditable by design, not by claim
Four commitments behind every calculation. Tap any to read the policy.
Tied to NIST + BIPM
Unit conversions trace back to recognized measurement standards.
Formulas on the page
Every calculator shows its inputs, method, and assumptions.
Rounding stated
Precision and final-rounding guidance for professional use.
Public corrections
Source or method issues have an open, documented review route.
Most-used tools
New: AI assistant connector
Use ExpertToolkit inside ChatGPT, Claude & Cursor
Call our NEC wire-sizing checks, material-density workflows, unit converters, and calculators directly from your AI assistant over MCP — every answer cites the standard it used. No sign-up, no API key.
A platform for technical and professional decisions
ExpertToolkit spans more than a thousand tools, references, formulas, and structured datasets. Calculators and converters are part of the toolkit — the platform around them is what makes a result usable: stated methods, cited sources, and reference pages you can return to.
Working tools across professional domains
Electrical and power, engineering and materials, HVAC and building systems, logistics, finance, and nutrition each get purpose-built workspaces. Wire-gauge tools check a gauge against NEC ampacity, run length, and voltage drop, then say what to change; density workflows move between volume and weight for steel, gravel, concrete, and fuels; every result names the standard edition it was computed against.
A structured reference layer, not just answer boxes
Behind the tools sit formula pages with derivations, variables, and worked examples; conversion tables with pre-computed rows for repeat lookups; datasets and comparisons for side-by-side decisions. When a number matters, the page that produced it also shows where it came from.
Units and conversions as the foundation
Length, weight, area, volume, temperature, speed, pressure, energy, and data size are covered by dedicated converters with canonical pairs like meters to feet and Celsius to Fahrenheit — the measurement backbone every other domain builds on, tied to recognized standards.
Calculators that expose every input
Mortgage, loan, compound-interest, depreciation, and percentage calculators keep each input on the page so a monthly payment or schedule is reproducible. Health tools cover BMI, BMR, body fat, and ideal weight, with the formula and its limits stated alongside the result.
Frequently Asked Questions
- Q
What does ExpertToolkit cover?
Working tools and reference material across electrical and power systems, engineering and materials, HVAC and building trades, logistics, finance, everyday measurement, and nutrition. Each domain combines interactive tools with formulas, tables, and datasets that state their methods, assumptions, and the standard edition behind each number.
- Q
When should I use a calculator, converter, formula page, or table?
Use calculators when you need a computed result from multiple inputs, converters when changing units, formula pages when you want derivation and context, and tables when you need fast repeat lookups across many values.
- Q
How accurate are results on ExpertToolkit?
Converters are tied to standard definitions, calculators use explicit formulas, and public routes are validated against golden test cases before release. You can review methodology and assumptions on each tool page before relying on output.
- Q
How should I handle rounding for professional work?
Use full-precision values during intermediate steps and round only at final presentation. For finance, align rounding with your reporting policy; for engineering/science, match significant figures to source measurement precision.
- Q
Can I trust a result without checking assumptions?
You should always validate assumptions for high-impact decisions. ExpertToolkit is built to make this easier by exposing formula context, definitions, and structured reference content rather than showing a black-box number.
- Q
How does search decide where to send my query?
Intent routing maps natural-language queries to the best-fit page type. For example, unit phrases route to converters, multi-input finance/health phrases route to calculators, and derivation-style phrases route to formula pages.
- Q
Is my input data private?
Recent query history is stored locally in your browser for convenience and not tied to account identity. You can clear local history any time from the homepage experience.
- Q
How do I verify a result before sharing it with my team?
Open the linked formula or reference block, confirm unit definitions and assumptions, then run a second sample case to confirm expected behavior. For recurring workflows, use tables for spot checks across ranges.
- Q
Is ExpertToolkit free to use?
Yes. Core calculators, converters, formulas, and reference tables are accessible without account setup or subscription paywalls.
Explore the full platform
Every tool, reference, formula, and table — organized by domain and capability.