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DoMoreKit · Tools to get more done
Work out a loan payment, a profit margin, your exact age or a time zone difference in seconds. 42 free calculators, converters and developer tools, with clear formulas and no sign-up.
Start with a calculation
Clear answers, no sign-up required.
The tools people use most, from loan and mortgage payments to percentages, units and time zones.
Estimate monthly payments and total repayment for a loan.
Estimate a mortgage payment after your down payment.
Find what percentage one number is of another.
Calculate profit margin as a percentage of revenue.
See how compounding grows an investment over time.
Find your exact age in years, months and days from your date of birth.
Convert length, weight, volume, area, speed, temperature, data and time units.
Convert a date and time between world time zones, including daylight saving.
Validate, pretty-print or minify JSON right in your browser.
Calculate your body mass index and see the adult weight category.
Work out the tip, the total bill and each person's share.
Find the hourly rate needed to reach an income goal.
10 tools
Percentage, Discount, ROI, Simple Interest and more.
View money & finance tools →9 tools
Profit, Margin, Markup, Break-Even and more.
View business tools →4 tools
Hourly Rate, Freelance Project Pricing, Freelance Income, Client Profitability and more.
View freelancer tools →11 tools
Age, Date Difference, Time Zone Converter, Unit Converter and more.
View everyday utilities tools →8 tools
JSON Formatter & Validator, Base64 Encoder/Decoder, UUID Generator, URL Encoder/Decoder and more.
View developer tools tools →Every calculator is free to use straight away. You never need an account to get an answer.
Calculations run in your browser. The numbers and text you enter are not sent to our servers.
Each tool shows its formula, a worked example and answers to common questions, so you understand the result.
Metric and imperial units, any currency and time zones worldwide, with no country-specific assumptions.
Developer
What makes a password strong, how entropy works, and practical rules for passwords, passphrases and password managers.
Money
Understand equated monthly instalments, the EMI formula, how tenure changes total interest and the difference between flat and reducing-balance rates.
Developer
When to use camelCase, PascalCase, snake_case, kebab-case and CONSTANT_CASE in code, files and URLs.
Money
Step-by-step formulas for percentage change, with examples for prices, salaries and growth, plus how to apply a percentage rise or fall.
Business
Calculate gross, operating and net profit margin step by step, with a worked example and tips for improving your margin.
Money
A practical way to estimate an affordable home price from your income, debts and down payment using common lending guidelines.
Yes. All calculators and tools are free to use and do not require an account.
Yes. Calculations happen in your browser, so the values and text you enter stay on your device and are not uploaded.
Tools use standard formulas that are shown on each page. Results are estimates for general information. For financial, tax, legal or medical decisions, check with a qualified professional.
Money and finance calculators (loan, mortgage, interest, ROI), business tools (profit, margin, VAT, break-even), freelancer tools, everyday utilities (age, time zone, unit converter, BMI) and developer tools (JSON, Base64, UUID).
Yes. Use the contact page to send us an idea or to report a mistake. We read every message.