Free online tools
A catalog of 81 tools for developers, finance, dates, and unit conversion. No sign-up — most tools run in your browser.
Popular tools
For developers
Password Generator
Generate strong passwords with length and character options.
Open →For developers
QR Code Generator
Create a QR code for URL, text, Wi‑Fi, or vCard. Optional logo and colors.
Open →For developers
JSON Formatter
Format JSON with indentation.
Open →For developers
Hash Generator
Hash text with MD5 or SHA-256 in your browser.
Open →For developers
Regex Tester
Test regular expressions with match highlighting.
Open →For finance
Mortgage calculator
Calculate monthly payment and interest overpayment.
Open →For developers
JSON / CSV / XML toolkit, JWT decoder, Base64, UUID, and other dev utilities.
JSON
JSON Formatter
Format JSON with indentation.
Open →JSON Validator
Validate JSON for syntax errors.
Open →JSON Minifier
Minify JSON into a single line.
Open →JSON → CSV
Convert a JSON array to CSV.
Open →JSON → TypeScript
Generate a TypeScript type from JSON.
Open →JSON → YAML
Convert JSON to YAML.
Open →JSON Compare
Find differences between two JSON objects.
Open →CSV
Utilities
JWT Decoder
Decode JSON Web Token header and payload.
Open →Base64 Encode / Decode
Encode and decode Base64 strings.
Open →UUID Generator
Generate UUID v4 identifiers.
Open →Password Generator
Generate strong passwords with length and character options.
Open →QR Code Generator
Create a QR code for URL, text, Wi‑Fi, or vCard. Optional logo and colors.
Open →Hash Generator
Hash text with MD5 or SHA-256 in your browser.
Open →URL Encode / Decode
Percent-encode and decode URL strings.
Open →Regex Tester
Test regular expressions with match highlighting.
Open →For construction
Calculators for construction and estimate tasks.
Steel pipe converter
Convert steel pipe meters to tons.
Open →Heating acts (SP 4.02.08-2024)
Fill heating system commissioning acts and download Word (.docx) files.
Open →Insulation acts (SP 1.03.04-2022)
Fill substrate and insulation acceptance acts and download Word (.docx) files.
Open →Hidden works & structures acts (SN 1.03.04-2020)
Fill hidden works inspection and critical structure acceptance acts and download Word (.docx) files.
Open →Roofing acts (SP 1.03.05-2023)
Fill the roofing works acceptance act and download a Word (.docx) file.
Open →Flooring acts (SP 1.03.06-2023)
Fill the flooring works acceptance act and download a Word (.docx) file.
Open →Welding acts (SP 1.03.08-2023)
Fill the welding works acceptance act and download a Word (.docx) file.
Open →Concrete & RC acts (SP 1.03.09-2023)
Fill the concrete and reinforced concrete works acceptance act and download a Word (.docx) file.
Open →Metal, timber & cladding acts (SP 1.03.10-2023)
Fill the metal, timber and light cladding works acceptance act and download a Word (.docx) file.
Open →Masonry acts (SP 1.03.13-2024)
Fill the masonry and reinforced masonry works acceptance act and download a Word (.docx) file.
Open →Foundations acts (SP 1.03.14-2024)
Fill the bases and foundations works acceptance act and download a Word (.docx) file.
Open →Windows & doors acts (SP 1.03.15-2024)
Fill the window and door openings works acceptance act and download a Word (.docx) file.
Open →Landscaping acts (SP 1.03.17-2025)
Fill the territory landscaping works acceptance act and download a Word (.docx) file.
Open →External water & sewerage network acts (SP 4.01.07-2024)
Fill external water supply and sewerage network test acts and download Word (.docx) files.
Open →Internal water & sewerage acts (SP 4.01.08-2024)
Fill internal water supply and sewerage system test acts and download Word (.docx) files.
Open →Ventilation acts (SP 4.02.07-2024)
Fill the natural ventilation acceptance act and download a Word (.docx) file.
Open →Equipment & pipeline insulation acts (SP 4.02.09-2024)
Fill thermal insulation acceptance acts for equipment and pipelines and download Word (.docx) files.
Open →District heating network acts (SP 4.02.10-2025)
Fill heat network installation and test acts and download Word (.docx) files.
Open →Heat points & boiler room acts (SP 4.02.11-2025)
Fill heat point and boiler room flushing and test acts and download Word (.docx) files.
Open →Gas supply acts (SP 4.03.02-2026)
Fill gas distribution system installation and acceptance acts and download Word (.docx) files.
Open →Gas consumption & chimney acts (SP 4.03.03-2026)
Fill internal gas and chimney acceptance acts and download Word (.docx) files.
Open →For finance
Finance calculators: mortgage, loans, VAT, investments, ROI, and salary.
Mortgage calculator
Calculate monthly payment and interest overpayment.
Open →Loan calculator
Annuity consumer loan payment calculator.
Open →Salary calculator
Convert gross salary to net with a tax rate.
Open →VAT calculator
Add or extract VAT from an amount.
Open →Compound interest calculator
Capital growth with compounding.
Open →Investment calculator
Future value with monthly contributions.
Open →Inflation calculator
Purchasing power of money over time.
Open →ROI calculator
Return on investment as a percentage.
Open →Freelance rate calculator
Hourly rate from desired annual income.
Open →Hourly → annual salary
Convert hourly rate to annual income.
Open →For images
Resize images and convert formats online in your browser.
Date & time
Date calculators: days between dates, age, working days, vacation, time zones.
Days between dates
Calculate the number of days between two dates.
Open →Days until date
How many days are left until a selected date.
Open →Age calculator
Exact age in years, months, and days.
Open →Days lived
Number of days lived since birth date.
Open →Working days calculator
Working days between dates (weekends excluded).
Open →Vacation calculator
Return-to-work date after vacation.
Open →Weeks between dates
Full weeks between two dates.
Open →Day of week
Find the weekday for any date.
Open →Week number
ISO week number of the year.
Open →Time zone converter
Convert time between time zones.
Open →Unix timestamp
Convert Unix timestamp ↔ date and time.
Open →Unit converters
Weight, length, temperature, volume, and power converters. Plus a universal unit calculator.
Universal unit converter
Convert any units: weight, length, area, volume, temperature, power.
Open →kg → lb
Convert kilograms to pounds.
Open →lb → kg
Convert pounds to kilograms.
Open →km → mi
Convert kilometers to miles.
Open →mi → km
Convert miles to kilometers.
Open →cm → in
Convert centimeters to inches.
Open →in → cm
Convert inches to centimeters.
Open →m² → ft²
Convert square meters to square feet.
Open →liters → gallons
Convert liters to US gallons.
Open →°C → °F
Convert Celsius to Fahrenheit.
Open →°F → °C
Convert Fahrenheit to Celsius.
Open →m → ft
Convert meters to feet.
Open →ft → m
Convert feet to meters.
Open →kg → oz
Convert kilograms to ounces.
Open →oz → g
Convert ounces to grams.
Open →kW → hp
Convert kilowatts to horsepower.
Open →hp → kW
Convert horsepower to kilowatts.
Open →
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