Free · no sign-up · runs in your browser
Computer and Tech Calculators Quick answers for everyday tech decisions
Seven calculators for the questions that come up at home and in small offices: plan speed, download time, NAS capacity, battery runtime, power banks on planes, screen shapes and screen sharpness. Each one shows its formula and the published figures it uses.
7 calculators
Pick a calculator
- Internet Speed CalculatorHow many Mbps your household needs
- Download Time CalculatorHow long a file takes at your speed
- RAID CalculatorUsable space and drive failures by RAID level
- Battery Life CalculatorLaptop runtime from Wh, health and watts
- mAh to Wh CalculatorConvert battery ratings and check FAA limits
- Aspect Ratio CalculatorRatios, missing sides and resizing
- PPI CalculatorPixel density from resolution and screen size
Start from the problem
Which calculator answers your question?
| Your question | Use |
|---|---|
| Is my internet plan big enough for the house? | Internet Speed Calculator |
| How long will this game, backup or upload take? | Download Time Calculator |
| How much space will my NAS drives give me? | RAID Calculator |
| How long will my laptop last unplugged, and is a new battery worth it? | Battery Life Calculator |
| Can I take this power bank on a plane? | mAh to Wh Calculator |
| Will this photo or video fit the screen without cropping? | Aspect Ratio Calculator |
| Is this monitor sharp enough at my desk? | PPI Calculator |
How they work
Built from published figures
Every calculator runs entirely in your browser; nothing you type is sent anywhere. Each page explains the formula behind the result and names the sources it relies on, such as the FCC’s broadband speed guide, the FAA’s lithium battery rules and the Windows battery report, so you can check the math yourself.
Each page also goes past the number: what a NAS will really show, how to measure your laptop’s actual power draw, what to check before paying for a faster plan. If a result surprises you, the page underneath it usually explains why.
About this toolkit
Who built these calculators
The calculators are built and maintained by Marcus Reed, who has spent more than a decade fixing laptops and desktops and writes the repair guides on Atlanta Computers. They are free to use and to link to, with no account and no limits. To suggest a calculator or report a result that looks wrong, use the contact page.
