Free online calculators

New this week

• Decision Wheel

  Enter a list of options, give it a spin, and let the wheel pick. Useful when the team can't decide where to eat, or when you genuinely cannot choose between two equally good ideas.

  In Fun

• Fuel Economy Converter

  Convert between MPG (UK), MPG (US), litres per 100 km and kilometres per litre. All four units stay in sync as you type, so you can see the same fuel economy four different ways.

  In Conversions

• Project Deadline Countdown

  Pick a deadline and see how many calendar days and working days remain. UK bank holidays come as a one-click preset and the mini-calendar shows you the working days at a glance.

  In Productivity

• SERP Snippet Preview Tool

  See exactly how your title and meta description will look in Google's search results, with the actual pixel-width truncation Google applies on desktop and mobile.

  In SEO

Featured calculators

One pick from each category. Browse the rest from the category links below or the all-calculators index.

• LLM Token Usage Calculator

  Estimate how many tokens a prompt and response will consume across OpenAI, Anthropic and Google models, and what that costs per call and per month.

  In AI

• Broadband Bandwidth Calculator

  Estimate the download and upload speeds your household needs based on streaming, video calls, gaming, smart devices, and remote work.

  In Broadband

• Domain Renewal True Cost Calculator

  See the real multi-year cost of a domain including the renewal price hike and add-ons like WHOIS privacy, email, DNS and SSL.

  In Business

• Cooking Measurements Converter

  Convert between cups, tablespoons, teaspoons, grams, ounces and millilitres for any common cooking ingredient. Recipe-friendly rounding.

  In Conversions

• Password Strength Calculator

  Score any password against length, character variety and common-password lists. See estimated time to crack and concrete suggestions to make it stronger.

  In Cybersecurity

• US Mortgage Calculator

  Work out your monthly US mortgage payment with principal, interest, property tax, home insurance, HOA and PMI broken out separately. Total interest and total cost over the life of the loan.

  In Finance

• Random Name Picker

  Paste a list, click pick, get a winner. Useful for raffles, classroom callouts, prize draws and any time you need a fair random choice from a finite set.

  In Fun

• BMI Calculator

  Work out your body mass index in metric or imperial units, with the WHO category and an honest note on what BMI can and cannot tell you.

  In Health

• Photo Resizer

  Resize and convert photos in your browser. Pick a width, a height, a format and a quality. Your image never leaves your device.

  In Images

• Percentage Calculator

  Work out a percentage of a number, what percent one number is of another, or the percentage change between two values.

  In Math

• iCal Event Generator

  Create a .ics calendar file for any event. Set the date, time, timezone, location and recurrence, then download and import into Google Calendar, Apple Calendar, Outlook, or any other calendar app.

  In Productivity

• UK Rent vs Buy Calculator

  Compare the lifetime cost of renting against buying a UK property, factoring in stamp duty, mortgage interest, maintenance, opportunity cost and rent inflation.

  In Property

• URL Slug Generator

  Turn any title into a clean, lowercase, hyphen-separated URL slug. Strips accents, punctuation and stop words. Validates against common length and character rules.

  In SEO

• Wedding Budget Calculator

  Enter your total budget and guest count to get a recommended spend breakdown across venue, catering, photography, music, flowers, attire, stationery, transport, and contingency.

  In Wedding

• Word Count Tool

  Live word, character, sentence and paragraph counts for any pasted text, plus fit-checks against tweet, meta description, SMS and SEO title limits.

  In Writing

See all calculators →

The rules of this site

WebCaretakers is a small, independent calculator hub run by Andrew Laws. The whole site is built on a short list of self-imposed rules:

• No sign-up, ever. If a tool needs an account, something has gone wrong in the design.
• Everything runs in your browser. The numbers you type never leave your device. There is no server-side maths, no logging of inputs.
• Show the workings. Every calculator has a "Prove it" panel that explains how the number was arrived at. You should never have to take the result on faith.
• Plain English. If a tool cannot explain itself without jargon, it has failed.