New Tools

T-Test Calculator

An online t-test calculator that quickly tells whether the difference between two group means is significant — enter the means, standard deviations, and sample sizes to get the t-value and p-value.

Top-Level Domain (TLD) Directory

Search 900+ top-level domain suffixes worldwide in one place, including type, managing organization, and registration restrictions.

Voltage Divider Calculator

Free online voltage divider calculator. Quickly calculate output voltage from input voltage and two resistor values. Ideal for electronics DIY, repairs, and education.

Variance Calculator

Free online variance calculator to quickly find sample variance, population variance, standard deviation, and mean. Easily evaluate data volatility and dispersion.

Normal Distribution Calculator

Input mean and standard deviation to quickly calculate the cumulative probability or quantile corresponding to a value.

Absolute Value Calculator

Enter a real or complex number to instantly calculate its absolute value (modulus).

Mass Flow Rate Calculator

Free online mass flow rate calculator. Enter density and volumetric flow rate to quickly calculate mass flow rate with automatic unit conversions.

Greek Alphabet Reference

Quickly query 24 Greek letters with uppercase, lowercase, pronunciation, and common usage scenarios.

Batch Coordinate to Address Converter

Batch reverse geocode latitude and longitude coordinates into detailed addresses. Supports Excel upload and export, processing up to 500 records per batch.

Batch Geocoding (Address to Coordinates)

Convert batch addresses to latitude/longitude coordinates; supports text paste and Excel upload/export; up to 500 entries per batch.

Batch Latitude & Longitude Converter

Batch convert coordinates between WGS84, GCJ02, and BD09 online. Supports text paste and Excel upload with easy data export.

Online Piano Keyboard

Play our free online virtual piano keyboard. Features selectable instrument tones, quick chord lookup, and MIDI/MP3 recording.

Room Measurement Calculator

Input room dimensions and doors/windows room by room, automatically calculate area and estimate tile, paint, and other material quantities

IRR (Internal Rate of Return) Calculator

Calculate internal rate of return (IRR) and payback period to assess project returns and break-even timeline.

NPV (Net Present Value) Calculator

Calculate Net Present Value (NPV) and determine project investment value.

Annuity Present Value Calculator

Quickly calculate the present value and future value of ordinary annuities, annuities due, and perpetuities, with synchronized output of annuity present value factors and future value factors to support pension, loan, and investment analysis.

Break-even ROI Calculator

Enter profit margin, return rate, and other cost proportions to quickly calculate break-even ROI and ROAS for ad spending, with sensitivity analysis included—see the safety threshold at a glance.

E-commerce ROI Calculator

E-commerce advertising ROI/ROAS profit and loss calculator that accounts for profit margins, return rates, and hidden costs to quickly assess whether your ad spending is profitable

Noise Meter Pro

Professional Noise Detector: A/C/Z Weighting, Spectrum Analysis, Data Export

Essay Paper Generator

Customize and generate blank A4 essay paper PDFs online. Features custom word count markers and headers for printable writing and manuscript paper.