LocalMini

Tool category

Calculators & Converters

Quick calculators for files, dates, aspect ratios, business planning, travel, and future spreadsheet-style tools.

Tool library

Tools in this category

Each tool is built for one practical task and includes its own focused page.

All tools
Runs in browser

File Size Calculator

Estimate file size from bitrate and duration, or convert between MB, MiB, GB, and GiB.

Runs in browser

Upload File Checker

Check file size, extension, image dimensions, and PDF page count against common upload rules locally.

Runs in browser

Date Difference Calculator

Calculate days, weeks, months, and years between two calendar dates in your browser.

Runs in browser

Percentage Calculator

Calculate percent of, what percent, and percentage increase or decrease locally.

Choosing a tool

Which calculator should I use?

Upload File Checker

Use this before an upload form when you need to check file size, extension, image dimensions, or PDF page count.

File Size Calculator

Use this for bitrate, duration, storage-unit conversion, and rough media file-size planning.

Date Difference Calculator

Use this to count days, weeks, months, and years between two calendar dates.

Percentage Calculator

Use this for percent of, what percent, percentage increase, percentage decrease, and everyday discount math.

Common use cases

What these tools are useful for

  • Check whether a file fits upload limits before submitting a form.
  • Estimate file sizes from bitrate, duration, or storage units.
  • Calculate date spans for deadlines, travel, projects, or schedules.
  • Work out percentages, increases, decreases, discounts, and ratios.
  • Use browser-local calculations without signing in or opening a spreadsheet.
Local processing: LocalMini calculators run in your browser and are designed for quick everyday estimates. They do not replace professional financial, legal, engineering, or compliance advice.

Related categories

KDP Tools

Open the dedicated KDP category for directional sales, royalty, and monthly profit planning tools.

Calculators & Converters FAQ

Are calculator results exact?

Simple arithmetic results are calculated in the browser, but some tools use practical estimates. Review important results before relying on them.

Do calculators upload my files or values?

Current LocalMini calculators are designed to run in your browser. File-checking tools inspect selected files locally for the checks shown on the page.

Can I use these calculators for official decisions?

Use them as quick helpers, not as a substitute for professional review, official requirements, or regulated compliance checks.

Which calculator should I start with?

Start with Upload File Checker for upload requirements, File Size Calculator for media planning, Date Difference Calculator for date spans, or Percentage Calculator for everyday percentage math. Self-publishing calculators are grouped separately under KDP Tools.