Online Developer Tools

A collection of free, open-source tools for developers, SEO experts, and marketers. Secure, fast, and privacy-focused.

Developer Tools

SEO Tools

Marketing Tools

Productivity Tools

Text Tools

Image Tools

PDF Tools

Calculators

Personal Loan Calculator

Calculate personal loan payments, interest, and credit score impacts.

Age Calculator

Calculate your exact age in years, months, days, hours and minutes.

Percentage Calculator

Calculate percentages — find X% of Y, percentage change, increase and decrease.

Random Number Generator

Generate cryptographically secure random numbers, roll dice, flip coins.

BMI Calculator

Calculate your BMI with metric or imperial units and see your category.

Tip Calculator

Calculate tips and split bills instantly. Choose tip percentage, divide among friends, see per-person totals with round up option.

Salary Calculator

Convert salary between hourly, weekly, biweekly, monthly & annual. Estimate take-home pay after taxes.

GPA Calculator

Calculate semester and cumulative GPA on a 4.0 scale.

Discount Calculator

Calculate sale prices, savings, and double discounts instantly.

Date Calculator

Calculate days between dates or add/subtract days from any date.

Compound Interest Calculator

See how your investment grows with compound interest and monthly contributions.

Loan Calculator

Calculate monthly loan payments with full amortization schedule. Export to CSV, PDF, or Excel.

Debt Payoff Calculator

Compare Snowball vs. Avalanche strategies to find the fastest, cheapest way to pay off your debts.

Mortgage Calculator

Calculate monthly mortgage payments with principal, interest, taxes, PMI, insurance & HOA. Free amortization schedule and loan comparison.

ROI Calculator

Calculate return on investment instantly. Compare investments, see annualized returns, analyze marketing ROI.

Profit Margin Calculator

Calculate profit margin, markup %, and net profit instantly. Convert margin to markup, find break-even revenue.

VAT Calculator

Add or remove VAT from any price. Pre-loaded rates for 40+ countries including UK, EU. Reverse VAT calculation.

Home Affordability Calculator

Calculate how much home you can afford based on income, debts, and the 28/36 rule. See monthly payment breakdown with taxes, insurance, and PMI.

Mortgage Refinance Calculator

Compare current vs. new mortgage, calculate break-even point, monthly savings, and lifetime cost impact of refinancing.

Auto Loan Calculator

Calculate your car payment with credit score-based rates, trade-in, down payment, and sales tax. New and used car support.

Retirement Savings Calculator

Project your retirement savings with compound growth, Social Security, inflation adjustment, and the 4% safe withdrawal rule.

Rent vs. Buy Calculator

Compare the true cost of renting vs. buying a home over time, including equity, taxes, PMI, maintenance, and investment opportunity cost.

Savings Goal Calculator

Find exactly how much to save daily, weekly, or monthly to reach any financial goal with compound interest and inflation adjustment.

Mortgage Payoff Calculator

See how much interest you save and years you cut by paying extra on your mortgage. Compare strategies: extra monthly, bi-weekly, or lump sum.