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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.

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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
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Health & Fitness

385 calculators

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

HealthSportsFood
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Science & Engineering

755 calculators

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

ConstructionConversionPhysicsChemistryEngineeringTechnology
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Business & Data

252 calculators

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

StatisticsBusiness
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Everyday Life

491 calculators

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

MathEveryday LifeEcologyEducation
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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.

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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.

Emergency Fund Calculator

Calculate your recommended emergency fund size based on monthly expenses and job stability. Shows monthly savings plan with timeline to reach your target.

An emergency fund calculator determines how much money you need to set aside as a financial safety net to cover unexpected expenses or income loss without going into debt. The standard guidance is to hold 3–6 months of essential living expenses in an easily accessible savings account — enough to cover job loss, major repairs, medical costs, or other financial shocks. The exact target depends on income stability, dependants, employment type, and existing financial commitments. and are key to understanding how an emergency fund fits your overall financial picture.

Without an emergency fund, unexpected costs are typically funded through credit cards or overdrafts — both of which carry high interest rates that turn a short-term setback into a long-term debt problem. Research consistently shows that the absence of a liquid emergency fund is the single most common reason financially stable people fall into problem debt. Even a small emergency fund equivalent to one month of expenses provides meaningful protection against the most common financial shocks.

  1. List all essential monthly expenses: rent or mortgage, utilities, food, transport, insurance, minimum debt payments, childcare. Exclude discretionary spending.
  2. Enter the total essential monthly expenses.
  3. Select your target months of coverage: 3 months (employed, stable income, no dependants, dual income); 4–5 months (moderate job security or one dependant); 6 months (self-employed, single income household, variable income).
  4. Emergency fund target = essential monthly expenses × target months.
  5. Check your current liquid savings against the target to find your funding gap.
  6. Divide the gap by a realistic monthly saving amount to get your timeline to fully funded.

Emergency fund target formula

Target fund = Essential monthly expenses × Coverage months

Coverage months guidelines: 3 months — salaried employee, stable employer, no dependants, dual income; 4 months — one dependant or moderate income variability; 5 months — sole earner or variable income; 6 months — self-employed, commission-based, or contract worker.

Monthly saving needed = (Target − Current savings) ÷ Months to target date

Worked example: Essential monthly costs: rent 900 + utilities 150 + food 400 + transport 200 + insurance 100 = 1,750/month. Self-employed, 6-month target = 10,500. Current savings 2,000. Gap = 8,500. Saving 500/month → fully funded in 17 months.

Using your emergency fund result

Where to keep your emergency fund

The emergency fund must be in a liquid, low-risk account: easy-access savings accounts with competitive interest; cash ISA or equivalent tax-advantaged savings wrapper; government-backed savings products (e.g. NS&I Premium Bonds in the UK, I-bonds in the US). Do not invest the emergency fund in stocks, funds, or fixed-term bonds — market falls often coincide with the economic conditions (recession, job loss) when you are most likely to need the money. The fund must be genuinely accessible within 1–3 working days in a real emergency.

Finance tips and best practices

Common mistakes to avoid

Savings account deposit protection varies by country — most developed markets have government-backed deposit insurance (FSCS in the UK up to 85,000; FDIC in the US up to 250,000; DGSD in the EU up to 100,000). Always verify that your savings provider is covered by the relevant protection scheme. Government savings products (NS&I in UK, I-bonds/T-bills in US, etc.) provide additional protection as they are backed directly by the national government. For debt advice if building an emergency fund feels impossible due to existing obligations, seek free advice from a government-funded or non-profit debt counselling service in your jurisdiction. This calculator is for informational purposes only.