Calcify unifies tax, finance, business, ecommerce and conversion tools into one polished, UK-first toolkit — fast, clear, and built for daily decisions.
Clean interfaces, precise outputs, and category depth that mirrors a modern finance product — without losing the speed of a static site.
Use the take-home pay calculator for a quick, reliable baseline, then branch into tax codes, VAT, ecommerce margins, or conversions.
Five focused hubs make it easy to explore Calcify's tax-first calculator library without hunting through dozens of pages.
PAYE, self-employed, landlord, VAT, deadlines and HMRC-friendly guides.
Mortgage, loans, salary tax, compounding and money planning tools.
VAT, corporation tax, forms, deadlines and self-employed support.
eBay profit, postage, pricing and seller-focused helper tools.
Unit, currency, time zone and utility tools for day-to-day use.
We turn thresholds, deadlines and tax bands into simpler cards, tools and explainers instead of walls of legal wording.
New sections are based on official UK guidance, then rewritten in plain English so normal humans can actually use them.
Use calculators, checkers and role-based paths to understand tax by interacting with it, not memorising it.
Jump straight to the tools and guides that fit how you earn.
A richer Calcify homepage, with Calcify-worthy depth and broader utility.
Project ISA growth, track this tax year's allowance and see the monthly amount needed to max it by 5 April.
Add savings, property, pension and debts to see your net worth, liquid position and debt ratio in GBP.
Compare snowball vs avalanche, estimate debt-free time and see which balance to attack first.
Compare your current mortgage with a new rate, fees and break-even point before you switch.
Estimate monthly repayments, balloon costs, total interest and full ownership cost for HP or PCP deals.
Estimate room wall and ceiling coverage, litres needed, tins to buy and likely spare paint.
Work out loan-to-value, deposit percentage and how much extra cash you may need to reach a lower mortgage band.
Estimate UK SPP using average weekly earnings, 1 or 2 weeks of leave and optional employer top-up.
Estimate UK SAP using average weekly earnings, the first 6 weeks at 90% pay and the next 33 weeks at the capped rate.
Estimate UK SMP using average weekly earnings, the first 6 weeks at 90% pay and the next 33 weeks at the capped rate.
Estimate UK SSP using weekly earnings, waiting days and qualifying work days.
Check if a monthly rent looks realistic using UK income multiples, take-home pay and debt costs.
Profit, postage and selling maths for marketplace work.
Mortgage, loan, VAT and money planning tools.
Units, currency, time zones and quick day-to-day helpers.
Return on investment & annualised CAGR from initial and final values.
Estimate break-even units, revenue needed and sales required to hit a target monthly profit.
Work out markup, gross margin, VAT impact, selling fees and the target price needed to protect profit.
Search tax tools, ecommerce calculators, finance pages, business guides and more.
Project future costs or convert money into today's value using compound inflation.
Estimate payoff time, total interest and the real cost of monthly card payments.
Estimate statutory redundancy pay using age, service and capped weekly pay.
Estimate your overtime rate, gross pay and rough take-home after tax and NI.
Estimate car value over time with an annual rate + optional first-year drop.
See if your savings plan will meet your goal with interest included.
Convert annual salary into monthly, weekly, daily and hourly pay.
Rough estimate of how much of a one-off bonus you actually keep after tax and NI.
See the rough net cost of paying more into your pension as a basic or higher-rate taxpayer.
Most people can earn £12,570 before income tax starts. It tapers away once income goes above £100,000.
Self Assessment online returns are due 31 January. Payments on account usually land in January and July.
PAYE, student loans, dividends, VAT, salary sacrifice, marriage allowance, pensions and common tax-saving checks.
If your situation involves company shares, property disposals, rental income or trusts, use calculators as a guide — then sanity-check with an accountant.
2025/26 & 2026/27 tax year — updated March 2026
A new guide every few days.
Transfer up to £1,260 of your Personal Allowance to your spouse or civil partner. See if you qualify, how to apply, and how much tax you could save.
New · 18 October 2026How splitting your Personal Allowance between two or more PAYE jobs works, when it helps, and why it changes your payslips but not your total tax bill.
New · 17 October 2026Practical strategies to make the most of your £12,570 Personal Allowance in 2026/27: use the Marriage Allowance, manage multiple jobs, avoid emergency codes, and protect your tax-free amount.
New · 12 October 2026Plain English. No jargon. Actually useful.
Who gets £1,000 or £500 of tax-free interest, when it disappears, and why rising rates catch people out.
📖 5 min readWhat your tax code means, why it changes, and how to check if it's wrong.
📖 4 min readWhy W1, M1 and X codes appear, and what to do if your first payslip looks wrong.
📖 5 min readWho can claim it, how the transfer works, and why backdating can turn a small relief into a bigger win.
📖 5 min readPay As You Earn explained — how your employer deducts tax and NI before you get paid.
📖 5 min readHow to register, what you can deduct, payment on account, and Making Tax Digital.
📖 8 min readAnnual allowance, salary sacrifice, carry forward — how pensions save you tax.
📖 6 min readPlan 1, 2, 4, 5, postgrad — thresholds, rates, and when it gets written off.
📖 4 min readCash, Stocks & Shares, Lifetime, Innovative Finance — your £20k tax shelter explained.
📖 5 min readWhen you sell assets for profit — rates, allowances, and the Bed & ISA trick.
📖 6 min readNil-rate bands, residence relief, trusts, and how to pass on wealth tax-efficiently.
📖 7 min readSalary vs dividends, the £500 allowance, and how to structure your pay.
📖 5 min readWhy it saves Income Tax and NI, plus the trade-offs to check before opting in.
📖 5 min readWho pays it, how adjusted net income works, and the smartest ways to reduce the hit.
📖 4 min readLast-minute UK tax moves to consider before 5 April.
📖 5 min readWho it affects, when it matters, and how to prepare without panic.
📖 6 min readThe £1,000 trading allowance, Self Assessment, and when HMRC needs to know.
📖 5 min readWhen you can claim tax relief for homeworking costs and what counts.
📖 3 min readWhat business mileage you can claim and how to keep records.
📖 3 min readFlat rate expenses for washing workwear, who qualifies, and backdating four years.
📖 3 min readWhich work-related memberships may qualify for tax relief.
📖 3 min readOur sources, methodology, and why we link to HMRC and GOV.UK.
📖 2 min readA visual breakdown of how gross salary turns into take-home pay.
📖 3 min readWhy a bonus feels smaller once PAYE and NI do their thing.
📖 3 min readA plain-English visual flow from gross rent to taxable profit.
📖 3 min readQuick guide to when uniform upkeep can be worth claiming.
📖 2 min readSpot fake texts, refund emails and urgent payment threats before you get caught.
📖 4 min readUseful planning ideas and reliefs worth knowing about.
Give up part of your salary for employer pension contributions. You save both income tax AND National Insurance — your employer saves NI too. At £50k salary, sacrificing £5k saves ~£1,800/year.
💚 Potential saving: £500 – £3,000/yearPut up to £20,000/year into ISAs. All growth, dividends, and interest are completely tax-free forever. Use Stocks & Shares ISA for long-term; Cash ISA for short-term savings.
💚 Tax-free: all growth & income inside ISARent out a furnished room in your home and earn up to £7,500/year completely tax-free. No need to declare it on your tax return if you stay under the threshold.
💚 Tax-free income: up to £7,500/yearIf your partner earns under £12,570, they can transfer £1,260 of their unused allowance to you (if you're a basic rate taxpayer). Saves up to £252/year and can be backdated 4 years.
💚 Potential saving: up to £1,260 (including backdating)When you donate to charity with Gift Aid, they claim 25p extra per £1. Higher rate taxpayers can claim back the difference — donate £100, get £25 back on your tax return.
💚 20-25% reclaim for higher rate taxpayersFamily Investment Companies, Business Asset Disposal Relief (10% CGT on first £1m), EIS/SEIS tax relief (30-50%), VCT dividends, and strategic pension contributions above £100k to recover personal allowance.
💚 Advanced strategies — consult a tax adviserEveryday tools plus the full imported Calcify tax library.
Estimate UK gas + electricity costs using kWh, rates and standing charges
Estimate Employer National Insurance and total payroll cost
Compare your new salary and monthly take-home pay
Estimate loan APR from payments, term and fees
Work out UK holiday entitlement, pro-rata allowance and leave remaining
Estimate UK SAP across the first 6 weeks and the remaining capped period
Daily calories, TDEE and simple macro targets
Estimate borrowing power, deposit impact and monthly cost
See how extra payments cut interest and term
Monthly budget planner for bills, spending and savings
Maintenance + tuition fee estimate (England)
Fees, postage and margin
Repayments, overpayments, LTV
Monthly costs and total interest
Weight, length, temperature and more
Slab volume + bag estimate (UK)
Business days between dates (UK)
Body Mass Index — kg / m² with unit options
Estimate body fat % from basic measurements
Estimate due date from LMP or conception
Exact age in years, months and days + days to next birthday
Convert drinks to UK alcohol units & kcal
Quick travel and pricing checks
Letter and parcel pricing
Income tax + NI + student loan
Monthly bill after discounts
How much tax on your property
Tax on shares & property profits
For company directors
How much you save with pension
Add or remove 20% VAT
Estate tax estimator
Repayment estimator
For limited companies
See how much you'd save
Transfer unused allowance
Income tax + Class 4 NI
High Income Child Benefit Charge
Estimate January + July payments
Landlord tax on property income
Quick estimate for subcontractors
Decode 1257L, BR, D0, K codes and more
Key HMRC dates in one place
Employee expense relief checker
See bands fill as income rises
Simple yes/no decision flow
Estimate what you actually keep
Salary to day rate and hourly pay
Build your deadline list + ICS download
Find the right HMRC form for your situation
Spot reliefs and thresholds worth checking
How much spare change you save by rounding purchases
Split bills, include tip and rounding
UK seller fees and true profit per sale
Split bills, round tips and per-person amount
How many months of expenses to save & monthly plan
Projected nest egg at retirement with contributions & growth
Estimate SDLT relief and quick tax on purchase
Price per 100g / per 1L / per item for easy grocery comparisons
Future value with regular contributions and compounding
Price after discount, money saved & per-person split
Estimate fuel used and trip cost (UK mpg / L/100km)
HMRC-style MAP: 45p/25p reimbursement
Estimate statutory holiday pay for hourly, weekly or irregular pay
Find the sales volume needed to cover fixed costs and reach target profit
Calcify uses published formulas, thresholds and standard assumptions to give quick estimates you can actually use.
We use UK tax bands, dividend rates, NI thresholds, student loan plans and common HMRC rules to generate quick estimates.
Where possible, follow through to official guidance for forms, edge cases and filing obligations.
Key pages are marked for the 2025/26 and 2026/27 tax years so you can see when a threshold might need re-checking.
Use extra caution with property disposals, trusts, benefits in kind, cross-border income and company/share transactions.
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