Global Index

Master Directory.

44+ free calculators across publishing, science, developer, finance, health, and lifestyle. All run in your browser — no account needed.

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Publishing

KDP & Self-Publishing

KDP Spine Width Calculator

Exact cover dimensions for KDP and IngramSpark.

Trim Size Registry

All supported book dimensions with bleed specs.

KDP Royalty Calculator

Net earnings per copy across all marketplaces.

Cover Templates

Margin and bleed layout blueprints.

Page Estimator

Estimate finished page count from word count.

Publishing Glossary

30+ publishing terms defined — PPI, bleed, royalties.

Developer Tools

Web & Security

JSON Validator

Validate, prettify, and minify JSON instantly.

Word Count

Words, characters, and reading time.

Hash Generator

SHA-256, SHA-1, and MD5 — browser only.

Base64 Encoder

Encode and decode Base64 strings.

UUID Generator

Generate RFC 4122 UUID v4 and v7.

Regex Tester

Test and debug regular expressions.

SQL Formatter

Format and inspect SQL queries.

Aspect Ratio

Calculate ratio from dimensions or vice versa.

IP Lookup

Network address discovery.

Developer Glossary

30+ developer terms defined.

Finance

Loans & Investments

Mortgage Calculator

Monthly payments and total interest.

EMI Calculator

Monthly instalment for any loan.

Compound Interest

Investment growth over time.

Auto Loan Calculator

Vehicle financing and total cost.

Investment Calculator

Portfolio growth projections.

Finance Glossary

30+ finance terms defined.

Science & Engineering

Physics & Mathematics

Ohm's Law Calculator

Voltage, current, resistance, and power.

Density Calculator

Mass, volume, and material density.

Thermal Expansion

Linear expansion from temperature change.

Stress Analysis

Mechanical load and safety margins.

Percentage Change

Increase, decrease, and multiplier.

Unit Converter

Imperial and metric conversions.

Statistics Calculator

Mean, median, standard deviation.

Health & Fitness

BMI · TDEE · Nutrition

BMI Calculator

Body Mass Index with weight classification.

TDEE Calculator

Daily calorie burn by activity level.

Macro Calculator

Protein, carb, and fat targets.

Body Fat Calculator

Navy method body fat percentage.

Lifestyle & Marketing

Everyday & Growth

Tip Calculator

Split bills and calculate gratuity.

Sleep Calculator

Best bedtimes based on sleep cycles.

GPA Calculator

Weighted GPA on 4.0 scale.

Fuel Cost Calculator

Trip fuel cost in MPG or L/100km.

ROI Calculator

Return on investment percentage.

Ad Spend Calculator

CPC, CPM, CTR, and CPA analysis.

Date Gap Calculator

Days, weeks, and months between dates.

Age Calculator

Exact age down to the day.