Category · 3 tools
Calculators tools
Quick arithmetic that is easy to get subtly wrong in your head. Each calculator shows the working, not just the answer, so you can sanity-check a figure before it lands in a document.
Aspect Ratio Calculator
Simplify a width and height to a clean ratio and scale it to any target width.
Percentage Calculator
Calculate percentages, percentage-of, percentage change, and add/subtract percentages.
Unit Converter
Convert between length, mass, temperature, area, volume, speed, digital storage and time units.
Questions about calculators tools
Are the calculators tools free to use?
Yes. All 3 tools in this category are free, need no account and have no usage limits. ToolzKit is funded by keeping the site cheap to run, not by gating features.
Does my data get uploaded anywhere?
Every tool in this category runs its processing in your browser using ordinary JavaScript. Your input is not sent to a server, and it is not written to storage when you leave the page.
Can I use these tools on a phone?
Yes. The layouts adapt to narrow screens, editors stack vertically instead of side by side, and copy buttons stay reachable without horizontal scrolling.
How do I find a tool quickly?
Press the forward slash key, or Ctrl+K on Windows and Cmd+K on macOS, to open the command palette from any page. Type a few letters and press Enter.
Related categories
- Time & DateTimestamps, durations and time zones
- ProductivityEveryday desk utilities
- Data & ConversionMove between JSON, CSV, YAML and number bases
Or see every tool across all 12 categories.