Battery Backup Calculator

Calculate backup time and required battery capacity

Calculation Mode

Find Backup Time

Calculate how long your battery will last

Find Required Capacity

Calculate needed battery capacity

Load Devices

= 100.00 W
Total Load: 100.00 W

Battery Configuration

Backup Time Result

1 × 100.00Ah @ 12V

5h 24m
Backup Time
100.00W
Total Load
540.00Wh
Usable Energy
50.00%
DoD

Formula

Backup Time = (Voltage × Capacity × Batteries × DoD × Efficiency) ÷ Load

Energy Breakdown

Battery Energy

Total Stored: 1,200.00 Wh
Usable: 600.00 Wh
Effective: 540.00 Wh

Battery Backup Calculator

Calculate backup time or required capacity for UPS systems, off-grid power, and emergency backup solutions.

Quick Tips

• Lead-acid: 50% DoD max

• Lithium: 80-90% DoD safe

• Allow 20% safety margin

• Consider temperature effects

Network Analysis

Website Status Checker
Check if a website is down for everyone or just you to ensure your site is always up and accessible to users.
What Is My IP Address?
Find out your IP address and get detailed IP information to help with network troubleshooting and security.
Internet Ping Test
Test the response time and connectivity of any server to ensure reliable network performance and troubleshoot connectivity issues.
DNS Lookup Tool
Look up DNS records and check domain configurations to troubleshoot network issues and improve website performance.
HTTP Request Tester
Free online HTTP request tester for external APIs. Test public REST APIs, send GET, POST, PUT, DELETE requests with custom headers and authentication.
HTTP Status Checker
Check the HTTP status code of any website to ensure it is working properly and accessible to users.
Meta Tag Analyzer
Analyze meta tags of any website to improve your SEO and search engine visibility.
MX Record Checker
Verify email server configurations and mail exchanger records to ensure your email is delivered reliably.
Page Load Time Tester
Measure how fast a webpage loads and analyze performance to improve your website loading speed.
Broken Link Checker
Find broken links on your website automatically to ensure your site is always up to date and user-friendly.
Memory Usage Tracker
Monitor memory usage of your web applications to optimize performance and ensure smooth operation.
SSL Certificate Checker
Check the SSL certificate of any website to ensure it is secure and protected.
Redirect Checker
Check the redirect chain of any website to ensure it is secure and protected.

Management

To Do List
Try our project management tool to effortlessly manage your to-do lists, organize tasks, boost productivity, and stay on track with your daily goals.
Best Daily Planner
Try the best daily planner we believe to boost productivity with key features like to do list, time-blocking for daily planning.
Time Spent Tracker
Track your time spent on activities, tasks, and projects to help you stay on top of your schedule and improve your productivity.
Reminder Tool
Set browser notifications for reminders, tasks, and alerts to stay on top of your schedule.
Progress Tracker
Track and manage progress on multiple items with customizable categories, options, and completion percentages in a flexible grid interface.
Kanban Board
Visual project management tool to organize and track work through customizable workflow stages with drag-and-drop task management.
Scrum Board
Advanced project management with multiple board templates, team collaboration, analytics, and agile workflow support for effective sprint planning.
Habit Tracker
Track your daily habits, build streaks, and achieve your goals with our comprehensive habit tracker. Monitor progress, set reminders, and stay motivated.
My Passwords List
Securely store and manage your passwords locally in your browser with IndexedDB. Features search, categories, import/export, and strong password generation.
Expense Tracker
Track your expenses, manage categories, set budgets, and monitor your spending with our comprehensive expense tracking tool featuring reports and analytics.

Timers

Exercise Timer
Perfect interval timer for workouts, HIIT, Tabata, circuit training, and exercise routines with customizable duration and repetitions.
Interval Timer
Set up custom interval timers for workouts or tasks to help you stay focused and productive.
Pomodoro Timer
Stay productive with this customizable Pomodoro timer to help you focus and get more done in less time.
Stopwatch
Simple, accurate stopwatch for precise timing of any activity, workout, or event with easy-to-use controls.
Countdown Timer
Create countdown timers in hours, minutes, or seconds to track events and deadlines with precision and ease.
Event Countdown Generator
Create countdown timers for events, holidays, and deadlines with customizable options for name, date, time and end description.
Sunrise & Sunset Countdown
Countdown to sunrise and sunset times, helping you plan your day with accurate, real-time daylight tracking.
Tide Times
Countdown to high and low tide times, helping you plan your day with accurate, real-time tide tracking.
1 Minute Timer
Set a 1-minute timer for quick tasks, short breaks, meditation, or any activity that needs precise timing.
2 Minute Timer
Set a 2-minute timer for quick tasks, short breaks, meditation, or any activity that needs precise timing.
3 Minute Timer
Set a 3-minute timer for quick tasks, short breaks, meditation, or any activity that needs precise timing.
4 Minute Timer
Set a 4-minute timer for quick tasks, short breaks, meditation, or any activity that needs precise timing.
5 Minute Timer
Set a 5-minute timer for quick tasks, short breaks, meditation, or any activity that needs precise timing.
10 Minute Timer
Set a 10-minute timer for quick tasks, short breaks, meditation, or any activity that needs precise timing.
15 Minute Timer
Set a 15-minute timer for quick tasks, short breaks, meditation, or any activity that needs precise timing.
20 Minute Timer
Set a 20-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
25 Minute Timer
Set a 25-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
30 Minute Timer
Set a 30-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
35 Minute Timer
Set a 35-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
40 Minute Timer
Set a 40-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
45 Minute Timer
Set a 45-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
50 Minute Timer
Set a 50-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
55 Minute Timer
Set a 55-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
60 Minute Timer
Set a 60-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
90 Minute Timer
Set a 90-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
120 Minute Timer
Set a 120-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.
240 Minute Timer
Set a 240-minute countdown timer for longer tasks, workouts, cooking, or extended focus sessions.

Time Zones

World Time Zones
Find current time in cities and countries around the world with comprehensive timezone information.
Time zones Lookup
Find accurate timezone information for any location worldwide by city or region with reliable, up-to-date data.
MDT Timezone
Current time in Mountain Daylight Time (MDT) with customizable display options and fullscreen mode.
EST to MST Converter
Convert Eastern Standard Time (EST) to Mountain Standard Time (MST) with interactive time picker, conversion chart, and quick reference.
MST to EST Converter
Convert Mountain Standard Time (MST) to Eastern Standard Time (EST) with interactive time picker, conversion chart, and quick reference.
EST to PST Converter
Convert Eastern Standard Time (EST) to Pacific Standard Time (PST) with interactive time picker, conversion chart, and quick reference.
PST to EST Converter
Convert Pacific Standard Time (PST) to Eastern Standard Time (EST) with interactive time picker, conversion chart, and quick reference.
EST to CST Converter
Convert Eastern Standard Time (EST) to Central Standard Time (CST) with interactive time picker, conversion chart, and quick reference.
CST to EST Converter
Convert Central Standard Time (CST) to Eastern Standard Time (EST) with interactive time picker, conversion chart, and quick reference.
MST to PST Converter
Convert Mountain Standard Time (MST) to Pacific Standard Time (PST) with interactive time picker, conversion chart, and quick reference.
PST to MST Converter
Convert Pacific Standard Time (PST) to Mountain Standard Time (MST) with interactive time picker, conversion chart, and quick reference.
CST to MST Converter
Convert Central Standard Time (CST) to Mountain Standard Time (MST) with interactive time picker, conversion chart, and quick reference.
MST to CST Converter
Convert Mountain Standard Time (MST) to Central Standard Time (CST) with interactive time picker, conversion chart, and quick reference.
CST to PST Converter
Convert Central Standard Time (CST) to Pacific Standard Time (PST) with interactive time picker, conversion chart, and quick reference.
PST to CST Converter
Convert Pacific Standard Time (PST) to Central Standard Time (CST) with interactive time picker, conversion chart, and quick reference.
EST to UTC Converter
Convert Eastern Standard Time (EST) to Coordinated Universal Time (UTC) with interactive time picker, conversion chart, and quick reference.
UTC to EST Converter
Convert Coordinated Universal Time (UTC) to Eastern Standard Time (EST) with interactive time picker, conversion chart, and quick reference.
PST to UTC Converter
Convert Pacific Standard Time (PST) to Coordinated Universal Time (UTC) with interactive time picker, conversion chart, and quick reference.
UTC to PST Converter
Convert Coordinated Universal Time (UTC) to Pacific Standard Time (PST) with interactive time picker, conversion chart, and quick reference.
EST to GMT Converter
Convert Eastern Standard Time (EST) to Greenwich Mean Time (GMT) with interactive time picker, conversion chart, and quick reference.
GMT to EST Converter
Convert Greenwich Mean Time (GMT) to Eastern Standard Time (EST) with interactive time picker, conversion chart, and quick reference.

Calculator

Age Calculator
Calculate your age in years, months, days, hours, minutes, and seconds with our age calculator.
Annual Mileage Calculator
Calculate your annual mileage and estimate fuel costs with our easy-to-use Annual Mileage Calculator.
BMI Calculator
Calculate your Body Mass Index (BMI) and understand your weight category with our easy-to-use BMI calculator supporting both metric and imperial units.
Erlang Calculator
Calculate call center staffing needs using Erlang B or Erlang C, factoring call volume, handling time, and service level to fine tune customer wait times.
IP Subnet Calculator
Calculate IPv4 and IPv6 subnets with CIDR notation. Determine network addresses, broadcast addresses, subnet masks, and host ranges for network planning.
Fuel to Distance Calculator
Calculate how far you can travel with a given amount of fuel, or determine how much fuel you need for a specific distance.
Paycheck Calculator
Easily estimate your take-home pay with our free Paycheck Calculator. Calculate net pay after taxes and deductions instantly.
Tip Calculator
Calculate tips and split bills easily. Perfect for restaurants, service providers, and group expenses with customizable tip percentages.
Day of the Year Calculator
Calculate the day of the year for any date with our easy-to-use tool.
Compound Interest Calculator
Calculate compound interest with additional contributions and compare different investment scenarios with interactive charts.
Savings Goal Calculator
Calculate how much money you need to contribute each month to reach your specific savings goal with compound interest calculations.
Loan Calculator
Calculate loan payments, total interest, and payoff scenarios for personal loans, auto loans, and mortgages. Compare loan options and analyze early payoff benefits.
Mortgage Calculator
Calculate monthly mortgage payments, PMI, amortization schedules, and analyze extra payments. Supports conventional, FHA, and VA loans with comprehensive cost analysis.
GPA Calculator
Calculate your Grade Point Average with weighted and unweighted systems, semester GPA calculation, and target GPA planning for academic success.
Investment Return Calculator
Calculate returns on stocks, bonds, mutual funds, and other investments. Factor in dividends, fees, taxes, and analyze dollar-cost averaging scenarios.
Watts to kWh Calculator
Convert power in watts (W) to energy in kilowatt-hours (kWh). Calculate energy consumption, electricity costs, and environmental impact for appliances and devices.
Battery Backup Calculator
Calculate battery backup time and required capacity for UPS systems, off-grid power, and emergency backup solutions with comprehensive energy analysis.

Random

Random Word Generator
Generate random words for writing prompts, creative exercises, or games with categories like nouns, verbs, adjectives, and compound words. Bulk generation with export options.
Random Quote Generator
Get inspired with random quotes from famous people, organized by categories like motivation, wisdom, and success.
Secure Password Generator
Generate secure passwords and passphrases with various types of strong passwords, passphrases, random passwords and pin codes.
Random Color Generator
Generate random colors with hex codes and explore color theory with interactive color wheels showing complementary, triadic, analogous, and monochromatic colors.
Random Color Picker
Pick random colors from your custom palette. Add, edit, and delete colors, then randomly select one or more for your projects.
Random Security Check
Automatically run random security checks on your web applications to identify vulnerabilities and strengthen your site's overall protection.
Random Name Picker
Easily and randomly select names from any list for giveaways, meetings, or decision-making with our simple selection tool.
Random Decision Maker
Make decisions easily by entering your question and options. Let our random decision maker help you choose when you can't decide.
Random Team Generator
Generate random teams from a list of participants. Perfect for sports, group projects, or any activity requiring balanced team division.

Engineering

Voltage Divider Calculator
Calculate output voltage, resistor values, power dissipation, and current for voltage divider circuits used in electronics and engineering.
Resistor Color Code Calculator
Decode resistor color bands to determine resistance values, tolerance, and power ratings for 4, 5, and 6-band resistors with visual representation.
Capacitor Value Calculator
Convert capacitor marking codes to values in pF, nF, and µF. Support for 3-digit codes, tolerance letters, and reverse lookup from value to code.
Wire Gauge Converter
Convert between AWG, millimeters, inches, square mm, square inches, and circular mils. Complete AWG chart with current ratings and resistance values.
Wave Frequency Calculator
Calculate wave frequency, wavelength, and speed using f=v/λ. Support for electromagnetic waves, sound waves, and custom mediums with unit conversions.
Fourier Series Visualizer
Interactive tool for visualizing Fourier series decomposition with real-time coefficient calculation, animation, and function approximation for signal analysis.
Sampling & Nyquist Calculator
Calculate Nyquist rate, check sampling sufficiency, analyze aliasing, and compute oversampling ratios for signal processing applications.
Beam Deflection Calculator
Calculate maximum deflection for simply supported and cantilever beams with point loads or distributed loads. Includes structural engineering formulas and design guidelines.
Bolt Torque Calculator
Calculate proper tightening torque for bolts based on material grade, preload requirements, and friction coefficients. Includes safety checks and engineering formulas.
Gear Ratio Calculator
Free professional gear ratio calculator for mechanical engineering. Calculate speed reduction, torque multiplication, compound gear trains, and mechanical advantage with real-time formulas and step-by-step solutions.
Molar Mass Calculator
Calculate molar mass and analyze chemical formulas with detailed elemental breakdown. Supports complex formulas, hydrates, parentheses, and provides mass percentages for chemistry applications.
Ideal Gas Law Calculator
Calculate pressure, volume, temperature, or moles using the ideal gas law (PV = nRT). Free calculator with multiple units, step-by-step solutions, and educational content for chemistry and physics.
Op-Amp Calculator
Calculate operational amplifier circuit parameters for inverting, non-inverting, differential, and integrator/differentiator configurations. Include gain, input/output impedance, and bandwidth calculations.
Heat Transfer Calculator
Calculate heat transfer rates for conduction, convection, and radiation. Include thermal resistance, heat exchanger analysis, and cooling calculations for engineering applications.
Transformer Turns Calculator
Calculate transformer turns ratios, primary/secondary voltages, currents, and power relationships. Include step-up/step-down calculations, impedance transformation, and efficiency calculations.
Power Electronics Calculator
Design and analyze DC-DC converters (buck, boost, buck-boost), calculate switching frequencies, inductor/capacitor values, and efficiency for power supply design.
Motor RPM Calculation
Calculate motor rotational speed from Hall-effect sensors, encoders, tachometers, and back-EMF measurements. Includes filtering, calibration, and performance analysis for motor control applications.
KVAR Calculator
Calculate required reactive power (KVAR) for power factor correction, capacitor bank sizing, and energy savings analysis for electrical systems and industrial applications.
HP to kW Motor Converter
Convert between horsepower (HP) and kilowatts (kW) for mechanical, electrical, and metric motor ratings with efficiency and load adjustments for engineering applications.

Screensaver

Black Screen
A free backlight bleed tester to check dead pixels, backlight bleeding. Test monitor, laptop, mobile screen or other display issues.
White Screen
Quickly detect dead pixels, screen flicker, or backlight bleed on any monitor with our advanced display testing tool.
Red Screen
Spot dead pixels, color uniformity issues, or backlight bleeding fast-ensure your screen quality with our pixel checker.
Green Screen
Instantly check for dead pixels, backlight bleed, or display defects to guarantee flawless screen performance.
Blue Screen
Test your monitor for dead pixels, backlight bleeding, and color inconsistencies in seconds with our display diagnostic tool.
Yellow Screen
Identify dead pixels, uneven backlighting, or screen defects easily-optimize your monitor's display quality now.
Purple Screen
Find and fix dead pixels, backlight bleeding, or display issues using our comprehensive screen testing solution.
Cyan Screen
Ensure perfect screen quality by detecting dead pixels, backlight bleed, and other monitor issues instantly.
Orange Screen
Diagnose dead pixels, backlight bleeding, or display problems quickly-improve your monitor's performance and viewing experience.
Pink Screen
Uncover dead pixels, backlight bleed, or screen defects fast with our user-friendly display testing tool.
Brown Screen
Verify your screen for dead pixels, backlight bleeding, or color issues to maintain top display performance.
Gray Screen
Easily detect dead pixels, backlight bleed, and other screen issues to ensure your display's optimal quality.
Lime Screen
Quickly identify and troubleshoot dead pixels, backlight bleeding, and display defects for a flawless viewing experience.
Time Screen
Display the local time on your screensaver, automatically adjusting to your current time zone for accurate, real-time clock display.
Date Screen
A screensaver that displays the current date and time. Real-time clock display on your desktop or device.
Clock Screen
Elegant clock screensaver displaying the current time with customizable styles, perfect for adding a sleek look to your screen.

Utilities

Webcam Tester
Quickly test your webcam and verify camera settings to ensure optimal video quality and proper device functionality.
Microphone Test
Test your microphone and verify settings to ensure clear audio quality and proper device performance for free.
Flashlight Tester
Test your flashlight and verify settings to ensure optimal lighting and proper device functionality for free.
Morse Code Translator
Free online Morse code generator. Convert text to Morse code, e.g.: SOS in morse code, and vice versa.
Cookie Manager
View, edit, and manage your browser cookies effortlessly to control privacy, enhance security, and customize your browsing experience.
Credit Card Number Validation
Validate credit card numbers using the Luhn algorithm to ensure they are valid and secure.
Online Tally Counter
Free online tally counter with multiple counters, labels, and total calculation. Perfect for counting, tracking, and tallying various items.
Spacebar Counter
Simple spacebar counter - press spacebar or click + button to count. Perfect for counting repetitions, events, or any activity.
Password Strength Tester
Test your password strength and learn how secure your password is. Get real-time feedback and tips to create stronger passwords.

Printable

Printable Calendar
Generate and download printable monthly calendars for any month and year. Perfect for planning, organizing, and printing.
January 2025 Calendar
Generate and download printable January 2025 Calendar. Perfect for planning, organizing, and printing.
February 2025 Calendar
Generate and download printable February 2025 Calendar. Perfect for planning, organizing, and printing.
March 2025 Calendar
Generate and download printable March 2025 Calendar. Perfect for planning, organizing, and printing.
April 2025 Calendar
Generate and download printable April 2025 Calendar. Perfect for planning, organizing, and printing.
May 2025 Calendar
Generate and download printable May 2025 Calendar. Perfect for planning, organizing, and printing.
June 2025 Calendar
Generate and download printable June 2025 Calendar. Perfect for planning, organizing, and printing.
July 2025 Calendar
Generate and download printable July 2025 Calendar. Perfect for planning, organizing, and printing.
August 2025 Calendar
Generate and download printable August 2025 Calendar. Perfect for planning, organizing, and printing.
September 2025 Calendar
Generate and download printable September 2025 Calendar. Perfect for planning, organizing, and printing.
October 2025 Calendar
Generate and download printable October 2025 Calendar. Perfect for planning, organizing, and printing.
November 2025 Calendar
Generate and download printable November 2025 Calendar. Perfect for planning, organizing, and printing.
December 2025 Calendar
Generate and download printable December 2025 Calendar. Perfect for planning, organizing, and printing.