1,000+ calculators and converters that show their work
Every result comes with the formula, the assumptions, and cited sources, backed by specialist engines for nutrition, material density, wire gauge, and finance.
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.
Explore by task
Pick a lane, land on a real answer
Four workspaces, hundreds of tools each. Jump straight to a worked example or open the full category.
Food and nutrition
Turn any food and portion into macros, calories, and comparisons.
Trades and materials
Density, wire gauge, and load math with the inputs on show.
Money and health
Multi-input calculators that spell out every assumption.
Reference and formulas
Worked derivations and repeat-lookup tables you can cite.
Specialist engines
Flagship engines built for high-intent decisions
Each flagship surface answers a practical question, then gives the user the context needed to trust it: assumptions, units, source notes, adjacent checks, and related reference pages.
Browse the platform
Use category hubs for discovery, or jump straight into a high-intent tool.
Most-used tools
New: AI assistant connector
Use ExpertToolkit inside ChatGPT, Claude & Cursor
Call our calculators, unit converters, and USDA nutrition data directly from your AI assistant over MCP. No sign-up, no API key.
What you can actually compute here
More than a thousand tools span everyday conversions and specialist engines for food, materials, electrical work, finance, and reference math. Here is the range, and why each area goes deeper than a single box.
Convert across every measurement family
Length, weight, area, volume, temperature, speed, pressure, energy, and data size each get dedicated converters with canonical pairs like meters to feet, kilograms to pounds, and Celsius to Fahrenheit. Where a value repeats often, a matching table lists dozens of pre-computed rows so you can scan a range instead of retyping.
Nutrition math down to the gram
A local food dataset turns portions into calories and macros: protein, carbs, fat, and fiber. Ask for chicken breast, salmon, almond butter, or oats at any serving weight, compare two foods side by side, or work backward from a macro target to the portion that hits it.
Trade and engineering estimates
Material-density workflows move between volume and weight for steel, gravel, concrete, sand, soil, and fuels. Wire-gauge tools pair AWG sizes with amperage, run length, and voltage-drop context, including EV-charger presets, so an electrical plan is grounded in real load figures rather than guesswork.
Finance, health, and formula depth
Mortgage, loan, compound-interest, and percentage calculators expose every input so a monthly payment is reproducible. Health tools cover BMI and BMR. Formula pages carry the derivation, variables, and worked examples behind each equation, from the area of a circle to compound growth.
Frequently Asked Questions
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.
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.
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.
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.
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.
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.
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.
Is ExpertToolkit free to use?
Yes. Core calculators, converters, formulas, and reference tables are accessible without account setup or subscription paywalls.