🧮2,000+ Free Calculators — finance, health, math, science & more. No signup needed.Browse All →

2000+ free tools — no signup required

2000+ free calculators, instantly.

Finance, health, math, science, unit conversion, business, food, sports, education, and daily planning. Every calculator includes the tool, formula notes, examples, FAQs, and related guides.

Explore categoriesSearch calculators
2,020free calculators
16topic categories
12formula engines
6FAQs per page
Freeno signup needed

Browse by topic area

Five calculator collections

Every calculator is organised into one of five topic areas. Click a collection to browse all the tools, sub-categories, and guides it contains.

Finance

137 calculators

Loans, mortgages, savings, investments, tax, budgets, retirement planning and more.

Finance
Explore collection

Health & Fitness

385 calculators

BMI, calories, nutrition, body composition, fitness training, sports and wellbeing.

HealthSportsFood
Explore collection

Science & Engineering

755 calculators

Physics, chemistry, construction, unit conversion, technology and technical design.

ConstructionConversionPhysicsChemistryEngineeringTechnology
Explore collection

Business & Data

252 calculators

Profit margins, ROI, pricing, statistics, payroll, revenue and business planning.

StatisticsBusiness
Explore collection

Everyday Life

491 calculators

Math, dates, discounts, tips, education, ecology and everyday household decisions.

MathEveryday LifeEcologyEducation
Explore collection

Browse by category

Calculator categories

Each category page works like a focused mini-library with topic clusters, descriptions, internal links, and calculator pages targeting specific search intent.

Finance

Plan loans, savings, investments, taxes, budgets, interest, and everyday money decisions with clear formulas and examples.

137 calculators

Health

Estimate health, fitness, nutrition, body measurements, and wellness metrics using practical reference formulas.

135 calculators

Math

Solve percentages, ratios, fractions, averages, geometry, algebra helpers, and common school or workplace math problems.

131 calculators

Construction

Estimate materials, areas, volumes, costs, paint, concrete, flooring, roofing, and renovation quantities.

130 calculators

Conversion

Convert units for length, weight, temperature, speed, volume, area, pressure, energy, and daily measurements.

125 calculators

Physics

Work with speed, force, energy, motion, electricity, waves, pressure, and classroom science formulas.

125 calculators

Chemistry

Use chemistry helpers for concentration, molarity, dilution, gas laws, molecular mass, and lab calculations.

125 calculators

Statistics

Analyze averages, probability, samples, confidence, variation, scores, and data interpretation problems.

125 calculators

Business

Estimate profit, margins, markup, inventory, payroll, pricing, revenue, productivity, and business planning metrics.

127 calculators

Everyday Life

Quick calculators for dates, time, tips, discounts, travel, fuel, recipes, shopping, and household planning.

110 calculators

Sports

Calculate pace, performance, training zones, scores, ratios, sports statistics, and fitness planning numbers.

125 calculators

Food

Scale recipes, estimate calories, cooking conversions, ingredient weights, nutrition, and meal planning quantities.

125 calculators

Ecology

Estimate energy use, water use, carbon footprint, recycling, transport impact, and sustainable living metrics.

125 calculators

Engineering

Work through mechanical, electrical, civil, and systems engineering formulas for practical design checks.

125 calculators

Education

Support learning with grade, score, GPA, reading, study time, classroom math, and academic planning calculators.

125 calculators

Technology

Estimate bandwidth, storage, download time, screen sizes, data transfer, battery life, and computing metrics.

125 calculators

Accuracy and transparency

Why United Calculator

Every page follows the same content standard: formula derivation, a worked example with real numbers, applicable laws or professional guidance, 6 plain-language FAQs, and links to 8 related tools.

Verified formulas

Each formula engine is based on published standards — TILA for loan calculations, METS tables for energy expenditure, ASTM standards for materials, and equivalents across 16 subject areas. The formula is shown in a code block on every result card so you can verify the calculation independently.

Professional context, not professional advice

Finance and health calculators cover applicable legislation (CFPB, NHS, OSHA) and reference professional thresholds (e.g. debt-to-income ratios accepted by lenders, WHO BMI categories). Every page includes a disclaimer — these tools are planning aids. Consequential decisions should be reviewed with a qualified professional.

No account, no tracking, no fee

Calculations run entirely in your browser. No data leaves your device. There are no login walls, no usage limits, no subscription tiers, and no premium paywalls. The only data stored is nothing — no cookies are set beyond what your browser requires to render the page.

Transparent methodology

Smart defaults come from published benchmarks — median UK household income from ONS, US average mortgage rate from Freddie Mac weekly surveys, average commute distances from the US Census ACS. Defaults are documented in the article body on each calculator page.

AboutDisclaimerPrivacy policyTermsCompliance Hub

Simple by design

How United Calculator works

Three steps from question to answer — no account, no subscription, no ads cluttering the result.

Search or browse

Type a topic into the search box or click a category. Each category is a mini-library of 125 calculator pages targeting specific questions — loan payments, BMI, tile counts, carbon footprint, and more.

Enter your values

Smart defaults are pre-filled so you get an immediate example result. Replace any field with your own data. Click the ? icon on any field for a plain-language explanation of what that input means.

Read, copy, and share

The result updates in real time. The formula is shown in a code block below the answer. Copy the result to your clipboard, share it to 8 social platforms, or scroll down for the full explanation, FAQs, and 8 related calculators.

Yeast Activation Calculator

Yeast Activation Calculator: calculate yeast activation for cooking and nutrition. Practical tips and worked examples.

The VAT / Sales Tax Calculator instantly adds or removes Value Added Tax from any price, showing the net amount, gross amount, and the tax portion separately. It covers preset rates for the UK (20%), EU (21%), US (8%), Australia (10%), and Canada (5%), letting you switch regions in a single click. Whether you are a freelancer issuing invoices, a consumer checking a receipt, or an accountant reconciling quarterly returns, accurate VAT arithmetic is non-negotiable. Use to understand overall costs, or to assess business profitability after tax.

HMRC's VAT registration threshold in 2024 is £90,000 annual turnover (raised from £85,000). Businesses above this threshold must charge VAT on goods and services, currently at the standard rate of 20%, with reduced rates of 5% on domestic energy and children's car seats. The EU VAT Directive 2006/112/EC harmonises VAT across member states while permitting local rate-setting — rates range from 17% in Luxembourg to 27% in Hungary. The United States has no federal VAT; instead, sales tax is levied at state and local level, meaning the effective rate varies by jurisdiction. Understanding the distinction between zero-rated (taxable at 0%, so input VAT is reclaimable) and exempt (outside the VAT system entirely) is critical for businesses with mixed supplies.

  1. Choose Add VAT to compute gross from net, or Remove VAT to extract net from a VAT-inclusive price.
  2. Enter the net or gross amount in the Amount field.
  3. Select a preset rate (UK 20%, EU 21%, US 8%, AU 10%, CA 5%) or type a custom rate in the VAT/Tax rate field.
  4. Read the three results: Net (excl. VAT), VAT amount, and Gross (incl. VAT).
  5. Use the Effective tax % figure to verify your arithmetic — it should equal your chosen rate when adding VAT.

VAT calculation formulas explained

Adding VAT: Gross = Net × (1 + Rate ÷ 100). The gross (VAT-inclusive) price equals the net price multiplied by one plus the fractional rate. This is the price the consumer pays.

Removing VAT: Net = Gross ÷ (1 + Rate ÷ 100). To reverse-calculate from a VAT-inclusive price, divide by the VAT factor. The VAT amount is then Gross − Net.

Worked example: A UK contractor invoices £1,000 net at 20% VAT. Gross = £1,000 × 1.20 = £1,200. VAT = £200. For a consumer seeing a £120 restaurant bill (inclusive of 20% VAT), the pre-tax amount = £120 ÷ 1.20 = £100; VAT = £20. The effective rate check: £20 ÷ £100 = 20% ✓

Understanding your VAT results

Net, VAT amount, and gross

The net amount is what the supplier earns before remitting VAT to HMRC. The VAT amount is collected on behalf of the government and must be declared on your quarterly VAT return. The gross is the total the customer pays. If you are VAT-registered and purchase goods for business use, you can generally reclaim the input VAT, making the net cost the true cost to your business.

For the effective tax rate: when adding VAT, this will always equal your chosen rate. When removing VAT from a gross amount, the effective rate as a percentage of gross (not net) will be lower — for example, removing 20% VAT from £120 yields 16.67% of gross. This matters for financial reporting and tax reconciliation.

Sports tips and best practices

Common mistakes to avoid

VAT rules are governed by HMRC (UK), the EU VAT Directive 2006/112/EC (EU), and equivalent national tax authorities worldwide. This calculator provides general information only and does not constitute financial, tax, or legal advice. Tax thresholds, rates, and rules change frequently — always verify current rates with HMRC or a qualified VAT adviser before issuing invoices or filing returns.