Choose a tool above to see its controls, a step-by-step walkthrough, practical tips, and answers to common questions. You can use every tool without creating an account.

Read the practical guides →

CHOOSE WITH CONFIDENCE

Make the right tool part of your workflow

Start with the result you need. Each tool below has its own settings, worked example, and troubleshooting advice so you can check the output before using it.

Percentage calculator

See the percentage and the calculation behind it. Percentage change uses the old value as its base. A zero base cannot be used for percentage shares or changes.

Discount calculator

Understand the savings, subtotal, and final estimated price. Tax is applied after the discount. This is a simple estimate; actual checkout totals can differ due to local rounding and tax rules.

Unit converter

Translate a measurement while keeping the units clear. KB, MB, and GB use decimal factors of 1,000. KiB, MiB, and GiB use binary factors of 1,024. Temperature conversion accounts for offsets.

Date difference

Count calendar days with an explicit end-date rule. The default count excludes the end date: Monday to Tuesday is one day. The end date must be on or after the start date.

Aspect ratio calculator

Keep a rectangle in proportion when its size changes. The target height is rounded to the nearest whole pixel. A one-pixel rounding difference can slightly change the exact ratio.

A SIMPLE ROUTINE

From task to finished result

STEP 01

Choose your starting point

Select the tool that matches your input and the change you want. Read its format requirements before selecting a file or entering values.

STEP 02

Adjust and process

Follow the tool’s quick-start steps. Check the selected files, units, or options before generating a result; a small settings change can affect the output.

STEP 03

Review and save

Inspect the result and download or copy it where offered. Keep your source file and choose a clear filename so you can find the finished version later.

HELPFUL ANSWERS

Frequently asked questions

A little clarity before you get started.

Which calculator tool should I choose?

Choose by the change you need. The tool cards explain each operation, and every tool page includes controls, a worked example, practical use cases, and specific limitations.

Can I use several tools in sequence?

Yes. Download or copy the result from the first tool, then use it as input in a compatible tool. Check the format and quality at each stage and keep the original separately.

Do these tools require an account?

No. All tools are available without signing in. An optional account saves your favorite tool list across devices.

What if I cannot get a result?

Read the troubleshooting section on the tool page, check the input format and any size limits, and try a smaller sample. Browser support and available device memory can affect file operations.