Instant answers with real-time (AJAX) updates

Instant answers with real-time (AJAX) updates—no page refreshes, ever. Do the math, see the result, download a PDF, and keep moving.

Why you’ll love it!

1 Live Results with AJAX Loading

Experience seamless, real-time results! Our calculators instantly update as you input data, providing immediate feedback without the need to reload the page. The AJAX loading feature ensures a smooth and efficient experience every time you use our tools.

2 Multi-Unit Input Options

Work in the unit that makes the most sense to you! Our calculators allow you to input values in a variety of units, making it easier to perform calculations across different measurement systems. Convert seamlessly between units like inches to centimeters, pounds to kilograms, and more!

3 PDF Download Option

Need a record of your calculations? With just a click, you can download your results in a clean, formatted PDF. Perfect for saving, sharing, or printing your results for future reference.

4 Instant Refresh Button

Got a new calculation or need to clear inputs quickly? Our handy refresh button instantly resets the tool, allowing you to start fresh without hassle. It’s perfect for quick corrections or experimenting with different values.

5 Step-by-Step Derivation

For those who prefer to understand the “how” behind the calculations, our step-by-step derivation feature breaks down the process. You’ll get a detailed explanation of every calculation, making complex concepts easy to follow and learn from.

6 Reference Table Integration

Need additional context or information while you calculate? Our calculators feature integrated reference tables, giving you access to important constants, conversion factors, and related data. Easily refer to these tables without leaving the tool to ensure accuracy and consistency in your calculations.

ROI (Return on Investment) Calculator

Fast ROI calculator: enter any two values—cost, gain, or ROI%—and get the third plus profit and ratio. Clear steps and downloadable PDF.

Taco Bar Calculator

Plan a taco bar fast: enter guests to get meat, cheese, dips, veggies, shells, tortillas & rice—live results, unit conversions, quick summary, PDF.

Alcohol Dilution Calculator

Quickly calculate how much water (or weak spirit) to add to reach your target ABV. Unit-aware, real-time results with contraction estimate.

Grams to Cups Converter

Convert grams to cups and cups to grams instantly. Choose ingredient, units (US/metric), see step-by-step math, summary, and download PDF.

ml to Grams Converter

Convert mL to grams fast with ingredient-aware density. Real-time results, unit switching, clear steps, and PDF export for kitchen and baking use.

Price Elasticity of Demand Calculator

Calculate PED fast with the midpoint method. Enter P₀, Q₀, P₁, Q₁ to see %ΔQ, %ΔP, elastic vs inelastic, and revenue impact—free today.

Percent Off Calculator

Calculate percentage off and savings instantly. Clean UI, live results, tax option, and downloadable PDF summary.

Margin Calculator

Free margin calculator: enter any two—cost, revenue, profit or margin—to get the rest. Supports %/decimal, currency symbol/subunit, and instant PDF export.

VAT Calculator

Instant VAT calculator to add or remove VAT, convert net ↔ gross, and get tax amount in real time. Currency options, tooltips, and PDF export. Free online.

PAY RAISE CALCULATOR

Calculate your pay raise by percent or amount. Convert hourly, weekly, monthly and annual pay to see new totals instantly, with step-by-step math and PDF export.

Annual Income Calculator

Free annual income calculator: convert hourly, weekly, or monthly pay to yearly salary and net after tax. Live updates, unit options, PDF summary.

Lottery Tax Calculator

Free lottery tax calculator: compare lump sum vs annuity after federal & state taxes. See net, yearly schedule, and PDF summary in seconds.

Most Useful Calculators

Elevation Grade Calculator

Calculate elevation grade from rise and run. See grade ratio, percent grade, and angle (°/rad/π rad). Supports metric and imperial units.

Dog Size & Adult Weight Calculator

Estimate your dog’s adult weight in seconds. Enter age and current weight to see the predicted adult size and category (Toy, Small, Medium, Large, Giant).

Dog Pregnancy (Due Date) Calculator

Estimate your dog’s due date from mating, LH peak, ovulation, or diestrus. See whelping window, days remaining, and weekday—fast and accurate.

Dihybrid Cross (Punnett Square) Calculator

Free dihybrid cross calculator: build a 4×4 Punnett square, see phenotype & genotype percentages, step-by-step derivation, and PDF export.

Pixels to Inches/CM/MM Converter

Body Shape Calculator

Discover your body type with our free Body Shape Calculator. Enter a few measurements to see instant results with guidance and size tips.

Margin and VAT Calculator

Enter VAT, cost, and margin or markup to get net price, gross price, and profit. Live results, %/decimal toggles, currency symbol/subunit, and PDF export.

Stock Calculator

Instant stock calculator—enter shares, prices, and fees to see net buy/sell, profit, ROI%, and break-even. Live updates + PDF export.

Age Difference Calculator

Find the exact age gap by age, birth year, or birth date. Get results in years, months, weeks, days—even a PDF. Free, fast, mobile-friendly.

All-in-One Home Loan & Mortgage Calculator

One tool for home loan EMI, mortgage APR, and PITI. Include fees, points, taxes, insurance, HOA and PMI. Fast, accurate, mobile-friendly.

Teen BMI calculator

Enter height, weight, age & sex to get BMI, BMI Prime, CDC BMI-for-age percentile and category. Real-time results, unit converters, and PDF export.

Helium Balloons Calculator

Calculate how many helium (or hydrogen) balloons you need to lift any weight. Preset sizes & custom diameter, unit-sync, instant results, steps, and PDF.

Bikini Calculator

Identify your body shape from bust, waist, high hip and hips. Instant results, unit switching, style tips, and PDF export—your free bikini fit guide.

RPM Calculator

Calculate engine RPM, speed, gear ratio & tire diameter with real-time results and unit conversions. Free, fast, mobile-friendly RPM calculator.

Roof Pitch Calculator

Free roof pitch calculator: enter rise and run to get slope ratio, pitch (X-in-12), degrees, % grade, and rafter length. Supports ft/in/m, shows formulas and steps, instant results & PDF.

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Accuracy & transparency

We implement widely accepted formulas and show each step so you can verify the logic yourself. Each calculator includes references or source notes when relevant.