---
title: "Free Online Calculators | BQ Calculator"
canonical: "https://calculator.bqtools.com/"
description: "Fast, accurate online calculators for finance, health, construction and everyday math. Free, private and calculated directly in your browser."
---

# Fast, accurate online calculators.

An ultra-fast calculator suite for finance, health, construction and everyday decisions—with transparent math, interactive visuals, local history and shareable scenarios.

## Choose a calculator

Built for immediate answers, with formulas and assumptions available when you want the details.

### Compound Interest Calculator

Project savings and investment growth with recurring contributions and compound interest.

### Mortgage Payment Calculator

Estimate principal and interest, taxes, insurance, HOA costs and total monthly mortgage payment.

### Loan Payment Calculator

Calculate installment-loan payments, total interest and the impact of optional extra monthly payments.

### Savings Goal Calculator

Estimate the monthly contribution needed to reach a savings target by a chosen date and interest rate.

### Calorie Deficit & TDEE Calculator

Estimate BMR, maintenance calories and a calorie target based on your activity and goal.

### BMI Calculator

Calculate adult BMI, view the standard category range and estimate the BMI 18.5–24.9 weight interval for your height.

### Concrete Calculator

Estimate concrete volume, waste allowance, premix bags and ready-mix requirements.

### Paint Calculator

Estimate interior wall paint from room dimensions, openings, coats and product coverage.

### Flooring Calculator

Estimate floor area, waste allowance, material quantity and full-box requirements for common flooring projects.

### Tip Calculator & Bill Splitter

Calculate tax, tip, total bill and the amount each person owes.

### Percentage Calculator

Solve common percentage-of, percent-of-total and percentage-change calculations instantly.

### Scientific Calculator

Evaluate arithmetic and scientific expressions with trig, logs, roots, powers, constants, memory and keyboard input.

### Unit Converter

Convert length, mass, area, volume, speed, temperature, time and digital-storage units locally in your browser.

### Date Difference Calculator

Find the exact number of days, weeks and calendar years, months and days between two dates.

## High-function tools without the noise

BQ Calculator keeps the interface focused on the calculation while still exposing the logic needed to understand the result.

Calculation logic and assumptions are documented in crawlable HTML, not hidden behind a black box.

Live recalculation, native Canvas visuals, three-way scenario comparison, CSV export, favorites, recent tools, shareable scenarios, keyboard quick-search, copy, print and local history.

One calculator registry drives cards, categories, counts, related links and the sitemap.

## Machine-readable resources

- Calculator registry: https://calculator.bqtools.com/calculators.json
- Site index: https://calculator.bqtools.com/llms.txt
- Full agent text: https://calculator.bqtools.com/llms-full.txt
- Agent discovery index: https://calculator.bqtools.com/agent-index.json