CalcKit — Free UK Calculators

Articles & Guides

Practical, jargon-free guides written for UK small businesses, freelancers, sole traders, and homeowners. Every article covers a real topic that comes up when running a business or managing personal finances in the UK.

Topics include understanding UK tax bands, setting profitable prices, calculating profit margins, buying property, and more. All articles are kept up to date with the latest HMRC rates and UK government guidance. No signup needed to read — just click and go.

All guides

property8 min read

How Much Rent Can I Afford in the UK? The 30% Rule and the 30x Check

The rule says spend no more than 30% of take-home pay on rent. The average UK renter now spends 41%. Here is how to work out your budget, what landlords actually check, and what to do when the numbers don't add up.

14 July 2026Read article →
health10 min read

Blood Pressure Ranges UK: What Your Numbers Mean and What to Do

Around 1 in 3 UK adults have high blood pressure. Most have no symptoms. Here are the NHS blood pressure categories, what a healthy reading looks like by age, and exactly what to do if your numbers are high.

13 July 2026Read article →
finance10 min read

Contractor vs Employee UK 2026/27: What You Actually Take Home

Contractors typically earn 20–30% more than equivalent employees — but only if you clear the real break-even, which most articles underestimate. Here are the actual numbers.

11 July 2026Read article →
finance10 min read

UK Pension Contributions 2026/27: How Much Should You Pay In?

The auto-enrolment minimum of 8% gets you into a pension, but for most people it won't be enough. Here is how pension contributions work in the UK in 2026/27 — the minimum rates, the qualifying earnings calculation, how tax relief actually saves you money, and what you need to contribute to retire on target.

10 July 2026Read article →
health9 min read

Child Growth Chart UK: NHS Centiles, Height & Weight by Age

UK child growth charts use nine centile lines, not a single 'ideal' target. A child on the 9th centile can be just as healthy as one on the 91st — what matters is whether they stay consistent. Here is how to read the charts, what the averages are by age, and when to speak to your health visitor or GP.

8 July 2026Read article →
finance10 min read

Child Benefit UK 2026/27: Rates, Eligibility & the High Income Charge

Child benefit pays £27.05/week for your first child and £17.90/week for each additional child in 2026/27. But if your household has a higher earner above £60,000, the High Income Child Benefit Charge quietly claws it back — and most families are overpaying or missing a straightforward fix.

7 July 2026Read article →
finance10 min read

UK State Pension 2026/27: How Much Will You Get?

The full new state pension is £241.30 a week from April 2026. But whether you get every penny of that depends on your NI record — and whether you know what to do about gaps.

6 July 2026Read article →
finance11 min read

How Much Do I Need to Retire in the UK? 2026 Pension Guide

Most pension guides tell you to 'aim for two-thirds of your salary'. Few show you the actual numbers: the PLSA retirement standards, how much state pension chips in, the pot size that covers the gap, and exactly what you need to save each month depending on when you start.

4 July 2026Read article →
finance11 min read

Statutory Maternity Pay UK 2026/27: How Much Will You Get?

SMP pays 90% of your average weekly earnings for 6 weeks, then £194.32 a week for 33 weeks. On a £35,000 salary that's about £539 in week 1 and £194 in week 8. Here's exactly how the numbers work.

3 July 2026Read article →
finance12 min read

Salary Sacrifice Pension UK: How Much Could You Save?

A basic rate taxpayer needs to spend only 72p to put £1 into their pension through salary sacrifice. A higher rate taxpayer spends 58p. Someone earning just over £100,000 spends 38p. Most people don't know these numbers — here's why they matter.

2 July 2026Read article →
finance8 min read

How Much is a Pay Rise Worth After Tax? UK 2026/27

A pay rise always looks bigger on paper than it feels in your bank account. Here is exactly how much of it you keep, by salary level.

1 July 2026Read article →
business11 min read

E-Commerce Pricing UK: How to Set Prices That Actually Make a Profit

Most UK ecommerce sellers know their product cost. Fewer account for platform fees, payment processing, shipping, and returns before they set a price — and those missing costs are exactly what turns a 40% margin into 8%.

30 June 2026Read article →
finance11 min read

1257L Tax Code Explained: What It Means for Your Pay (2026/27)

1257L is the tax code on most UK payslips — but BR, K, 0T, and M1 codes can quietly cost or save you hundreds of pounds a year. Here's what every common code actually means.

25 June 2026Read article →
finance11 min read

What Does Pro Rata Mean? UK Salary and Holiday Guide 2026

A £30,000 full-time role paid pro rata for 3 days a week isn't simply £18,000 — depending on which method your employer uses, you could be paid two genuinely different amounts. Here's how to check.

25 June 2026Read article →
finance10 min read

How Long Will It Take to Save? UK Savings Goal Guide 2026

Saving £200 a month with no interest takes 50 months to reach £10,000. Add a 4.5% savings rate and it's done in 44 months. Here is exactly how the maths works.

24 June 2026Read article →
business11 min read

What is ROI? How to Calculate Return on Investment (UK Guide)

Spend £500 on a marketing campaign and make £2,000 in sales, and your ROI is 300% — but that number alone tells you almost nothing without context. Here is how to calculate and interpret ROI properly.

23 June 2026Read article →
health11 min read

TDEE and Calorie Needs UK: How Many Calories Do You Actually Need?

The NHS says adults need around 2,000–2,500 calories a day. Your actual number could be 1,600 or 3,200 depending on your body and activity. Here is how to find your real figure.

22 June 2026Read article →
finance12 min read

Self-Employed Tax UK 2026/27: Income Tax, NI and Payment Dates

Your first self-employed tax bill is often 150% of what you expect — because of payments on account. Here is exactly what you owe in 2026/27 and why the first year catches people out.

21 June 2026Read article →
property11 min read

Mortgage Affordability UK: How Much Can You Borrow in 2026?

A £40,000 salary typically supports a mortgage of £160,000–£180,000. Here is exactly how UK lenders calculate affordability in 2026 — income multiples, debt, and self-employed income.

20 June 2026Read article →
finance11 min read

National Insurance UK 2026/27: Rates, Thresholds and What You Pay

How much National Insurance you pay in 2026/27 — employee and employer rates, NI at every salary level, self-employed Class 4, and how your NI record affects your State Pension.

19 June 2026Read article →
finance12 min read

Dividend Tax UK 2026/27: Rates, Examples, and How to Pay

Dividend tax rates went up by 2 percentage points from April 2026. Here is what you pay in 2026/27, with worked examples at every tax band and a director's strategy guide.

18 June 2026Read article →
health9 min read

How Much Sleep Do You Need? UK Sleep Guide 2026

Most adults need 7–9 hours of sleep, but the time you wake up matters as much as the hours you clock. Here is how to calculate your ideal bedtime.

17 June 2026Read article →
finance7 min read

What is Break-Even Point? Formula, Examples and How to Calculate It

Before you launch a product or set a price, there's one number you need to know: how many units do you have to sell before you stop losing money? That's your break-even point.

17 June 2026Read article →
finance8 min read

Should You Overpay Your Mortgage? The UK Guide for 2026

Overpaying £200 a month on an average UK mortgage can save over £20,000 in interest and cut years off your term — but it isn't always the right call. Here's how to decide.

15 June 2026Read article →
finance8 min read

How to Pay Yourself as a Limited Company Director (UK 2026)

The salary and dividend split you choose can be worth thousands of pounds a year. Here is exactly how UK limited company directors pay themselves tax-efficiently in 2026.

13 June 2026Read article →
property9 min read

How to Calculate Rental Yield: Gross, Net & UK City Comparison (2026)

Gross rental yield = annual rent ÷ property value × 100. That's the easy part. Here's how to calculate net yield, what counts as good in 2026, and how tax changes the real number.

11 June 2026Read article →
finance9 min read

What is IR35? Inside vs Outside Explained for UK Contractors (2026)

IR35 decides whether your contract is taxed like employment or like a business. Here is what inside and outside IR35 actually mean, who decides, and the real cost difference.

11 June 2026Read article →
finance9 min read

How to Convert Salary to Hourly Rate UK — Complete 2026 Guide

A £30,000 salary sounds like £15.38 per hour. After tax, NI, and a daily commute it is closer to £12.15. Here is the exact formula, a gross vs net comparison at every salary level, and how to use your hourly rate to compare job offers.

9 June 2026Read article →
health8 min read

How Much Water Should You Drink a Day? UK Guide (2026)

The NHS says 6–8 glasses a day. But a 90kg runner needs nearly double what a 60kg desk worker needs. Here is how to calculate your actual daily water target — and what actually counts toward it.

30 May 2026Read article →
finance8 min read

How to Calculate VAT in the UK — Complete Guide (2026)

Multiply by 1.2 to add VAT. Divide by 1.2 to remove it. Never subtract 20% — that gives the wrong answer. Here is everything else you need to know about UK VAT calculations.

29 May 2026Read article →
health9 min read

What is a Healthy BMI? UK NHS Weight Chart & Ranges (2026)

A healthy BMI in the UK is 18.5–24.9. Below 18.5 is underweight by NHS standards — a threshold that comes with real health risks. Here is what the NHS actually says, the full height chart, and what to do.

26 May 2026Read article →
property11 min read

Land Transaction Tax Wales: Complete LTT Guide for 2026

Buying property in Wales means paying Land Transaction Tax, not stamp duty. The rates differ, the rules differ, and first-time buyers get no relief. Here is exactly how it works in 2026.

25 May 2026Read article →
finance10 min read

Salary Sacrifice Explained: How It Works, What You Save, and When to Skip It

Most salary sacrifice guides give you one dry example. This one gives you real numbers at different salary levels, the catches nobody warns about, and the £100,000 trap most articles skip.

20 May 2026Read article →
finance8 min read

Freelancer Day Rate: How to Calculate Yours in 2026

Setting your freelancer day rate by guessing leaves real money on the table. Here is the formula, the buffers, the benchmarks, and the phrases that hold your rate under client pressure.

12 May 2026Read article →
finance9 min read

UK Freelance Rates in 2026: What to Charge by Role

Undercharging by just £50 a day costs £10,000 a year. Here are the 2026 UK freelance rate benchmarks by role — and the formula to calculate your exact floor.

8 May 2026Read article →
finance8 min read

Limited Company vs PAYE UK: Which Puts More in Your Pocket?

The gap between limited company and PAYE can reach £10,000–£20,000 per year. Here is exactly how the numbers work — and which structure wins for your situation.

5 May 2026Read article →
finance6 min read

Markup vs Margin: The Difference Between Margin and Markup Explained

Confusing markup and margin is one of the most common pricing mistakes in business. Here is the clear explanation.

25 March 2026Read article →
property7 min read

Stamp Duty UK 2025/26 — Complete Guide to SDLT

Stamp duty is one of the biggest costs of buying a home. Understanding exactly how much you owe before you buy is essential.

20 March 2026Read article →
finance9 min read

How Much to Charge as a Freelancer UK — 2026 Rate Guide

Setting the right freelance rate is one of the biggest challenges for new freelancers. Too low and you struggle. Too high and you lose clients.

10 March 2026Read article →
finance9 min read

How to Price Your Products: The Complete UK Guide

Pricing is one of the most impactful decisions you will make. Get it right and your business thrives. Get it wrong and you work hard for nothing.

5 March 2026Read article →
finance6 min read

What is Profit Margin? A Complete Guide for UK Businesses

Profit margin is one of the most important metrics for any business. Here is everything you need to know, explained simply with real examples.

1 March 2026Read article →
finance10 min read

UK Tax Brackets & Income Tax Bands 2025/26 — Thresholds & Personal Allowance

Everything you need to know about UK income tax for 2025/26 — rates, thresholds, and how to calculate your tax bill.

15 February 2026Read article →