Bits&Bobs
Odd little tools that just work. Free, quick, and nobody asks for your email.
UK Salary Calculator
Take-home pay after income tax, National Insurance, pension and student loans, with Scottish rates, tax codes, bonuses and overtime.
Bonus After Tax Calculator
What a UK bonus is worth after income tax, National Insurance and student loan, and what you gain by sacrificing some of it into your pension.
Contractor Calculator
What a day rate is worth through a limited company, an umbrella or as a sole trader, side by side with a permanent salary, holidays and pension included.
Car Finance Calculator
Compare PCP, hire purchase, a personal loan and leasing on the same car: monthly payments, total paid and the real cost once the car's value is counted.
Stamp Duty Calculator
Stamp duty on a home in England, Scotland or Wales for movers, first-time buyers and second homes, band by band, with the total cash you need to buy.
Mortgage Calculator
Monthly repayments, total interest, and a full amortization breakdown for any home loan.
Mortgage Overpayment Calculator
See how much interest and how many years you save by overpaying your mortgage each month or with a lump sum.
Compound Interest Calculator
Watch savings and investments grow with compounding, regular contributions, and a year-by-year chart.
Inflation Calculator
What money from any year since 1800 is worth today, whether your pay has kept up with prices, and what things will cost in future.
Emergency Fund Calculator
How long your savings would last if your pay stopped, at normal spending and cut back to essentials, and how long it takes to build a safety net.
Percentage Calculator
Every percentage question in one place: X% of Y, percentage change, increases, and discounts.
Arrow Spine Calculator
See how cutting a shaft or changing point weight shifts an arrow's effective spine, with draw weight equivalents.
Commute Time Calculator
How many hours and days a year your commute really takes, what it costs, and how much working from home would give back.
Countdown Calculator
Days, hours, minutes and seconds until any date, ticking live, plus the weeks, sleeps, weekends and working days to go.
Garden Materials Calculator
How much topsoil, compost, mulch, bark, gravel or sand you need: cubic metres, litres, weight, bags or bulk bags, and the cheapest way to buy it.
Raised Bed Calculator
How much topsoil, compost and manure fills your raised beds, in bags or bulk bags, plus the boards and posts to build them and what it all costs.
Lawn Calculator
How much grass seed or turf your lawn needs, with paths, beds and sheds taken out, plus the topsoil, feed and water to get it going and what it all costs.
Patio and Paving Calculator
How many patio slabs to order with every cut counted on a plan, plus the MOT sub-base, sharp sand, cement, jointing, fall and total cost.
Water Butt Calculator
How much rain your roof can catch, what size water butt to buy, how often it would overflow or run dry, and what it saves on a water meter.
Solar and Battery Payback Calculator
What solar panels and a home battery would generate, save and earn, hour by hour through a year, and how many years they take to pay for themselves.
Drip Irrigation Calculator
How many drippers your tap can run per zone, how long to water each zone, how much water it uses a day and a week, and how long to flush the pipes.
TV Viewing Distance Calculator
How far to sit from your TV, or how big a TV to buy for your room. Drag the sofa on a floor plan and see when 4K detail is worth it.
Unit Converter
Convert length, weight, volume, temperature, speed, fuel economy, data, pressure and more across 300 units, including mpg to L/100km and stone to kg.
Dice Roller & Coin Flip
Roll up to five dice, from a d4 to a d20, or flip a coin and call it, with the total and a tally of what came up.
Text Diff Checker
Compare two texts and see every line and word that was added, removed or changed, side by side or inline.
Encoder & Decoder
Encode and decode Base64, URLs, HTML entities, hex and Unicode escapes, with proper UTF-8 handling and clear errors when something will not decode.
JWT Decoder
Decode a JSON Web Token to read its header, claims and expiry in plain English, and check an HMAC signature, without the token leaving your browser.
Cron Expression Builder
Build or decode a crontab schedule field by field, read it in plain English and see the next five runs in any time zone.
Regex Tester
Test a JavaScript regular expression on your own text with live highlighting, groups, replace, a plain-English explanation and code for six languages.
Free online calculators, built for the UK
Bits & Bobs is a small, growing collection of calculators for the questions that come up in real life: what your salary is worth after tax, what a mortgage costs each month and how much overpaying saves, how savings grow with compound interest, and quick percentage maths. Every tool runs in your browser, works on your phone, and gives you a link you can share with the numbers already filled in.
The money tools use current HMRC rates and standard lender formulas, and each page explains how the calculation works so you can check it yourself. They are estimates for planning, not financial advice.