🧮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.

Food Hygiene Calculator

Food Hygiene Calculator: calculate food hygiene for students and teachers. Clear steps and worked examples.

A daily calorie calculator estimates how many calories you should consume each day to achieve your specific goal — whether that is maintaining your current weight, losing fat, or gaining lean muscle. It combines your Basal Metabolic Rate (the energy your body needs at rest), an activity adjustment for your lifestyle, and then applies the appropriate calorie offset for your goal. Most nutrition guidelines are ultimately expressed in calorie terms because the energy balance equation — calories in minus calories out — remains the primary determinant of body weight over time, even when the mechanisms are complex. and are essential companion tools for tracking nutrition alongside calories.

The quality of calories matters alongside quantity: 2,000 kcal of varied whole foods with adequate protein, fibre, vitamins, and minerals supports health very differently from 2,000 kcal of ultra-processed food with the same macronutrient profile on paper. Calorie targets are a useful starting framework, not a complete nutrition guide.

  1. Enter your current weight, height, and age to calculate your BMR using the Mifflin-St Jeor equation.
  2. Select your activity level — be honest; most people overestimate and the error compounds into a higher calorie target than needed.
  3. Select your goal: lose fat, maintain weight, or gain muscle. The calculator applies the appropriate calorie adjustment.
  4. Read your daily calorie target and the recommended macronutrient split (protein, carbohydrate, fat).
  5. Track your actual intake for 2 weeks using a food diary app (e.g. Cronometer, MyFitnessPal) and compare to your weight trend to calibrate the estimate.
  6. Adjust the target by 100–200 kcal based on your observed rate of change — this is more accurate than any formula alone.

Daily calorie target formula

Step 1 — BMR (Mifflin-St Jeor): Male = 10W + 6.25H − 5A + 5; Female = 10W + 6.25H − 5A − 161 (W=kg, H=cm, A=age)

Step 2 — TDEE = BMR × Activity Multiplier (1.2–1.9)

Step 3 — Calorie target: Fat loss = TDEE − 300–500 kcal; Maintenance = TDEE; Muscle gain = TDEE + 200–300 kcal

Worked example: 28-year-old female, 65 kg, 165 cm, lightly active. BMR = 650 + 1,031 − 140 − 161 = 1,380 kcal. TDEE = 1,380 × 1.375 = 1,898 kcal. For moderate fat loss (350 kcal deficit): target 1,548 kcal/day. Expected rate: approximately 0.35 kg/week fat loss.

Understanding your daily calorie result

Calorie target ranges by goal

Fat loss: a 250–300 kcal deficit produces ~0.25 kg/week fat loss (sustainable, preserves muscle); 500 kcal deficit produces ~0.5 kg/week (aggressive but manageable for most); 750–1,000 kcal deficit risks muscle loss and metabolic adaptation. Minimum recommended intakes: 1,200 kcal/day for adult females; 1,500 kcal/day for adult males — below these levels, nutritional adequacy is very difficult to maintain without medical supervision. Muscle gain: a 200–300 kcal surplus produces approximately 0.25–0.5 kg/month of lean mass gain in trained individuals; larger surpluses gain fat disproportionately.

Education tips and best practices

Common mistakes to avoid

Daily calorie targets produced by this calculator are estimates based on published BMR formulas and population-level activity multipliers. Individual calorie needs vary due to genetics, metabolic health, medications, and hormonal factors. This calculator does not constitute dietary, nutritional, or medical advice. For medically supervised weight loss, eating disorder recovery, pregnancy nutrition, or performance athlete planning, consult a registered dietitian (RD) or GP. UK government dietary reference values are published by the Scientific Advisory Committee on Nutrition (SACN) at gov.uk.