CVSS calculatorCalculate CVSS v3.1 base scores for security vulnerabilities. Select metrics, get an instant score, severity rating, and vector string — ready to paste into a report.
Password entropy calculatorFind out how strong a password really is. Enter a sample or build one from character set and length — get entropy in bits, crack time estimates, and pattern warnings.
SIEM log volume estimatorEstimate SIEM ingestion volume from log source counts or a direct event rate. Get GB/day, GB/month, TB/year, and stored volume after compression.
eGFR calculator (CKD-EPI)Estimate glomerular filtration rate using the CKD-EPI 2021 equation. Race-free formula with KDIGO CKD staging. Enter age, sex, and serum creatinine.
Creatinine clearance calculatorEstimate renal function using the Cockcroft-Gault formula. Actual, ideal, and adjusted body weight results. Metric and imperial units.
Body surface area calculatorCalculate body surface area using the Mosteller formula. Used for chemotherapy dosing and cardiac index. Metric and imperial units.
Corrected calcium calculatorCorrect serum calcium for albumin using the Payne formula. Colour-coded result from hypocalcaemia to severe hypercalcaemia. Enter calcium in mmol/L and albumin in g/L.
Anion gap calculatorCalculate standard and albumin-corrected anion gap from sodium, chloride, bicarbonate, and albumin. Colour-coded from low to significantly elevated. Figge albumin correction included.
Ideal body weight calculatorCalculate ideal body weight and adjusted body weight using the Devine formula. Enter sex, height, and actual weight. Metric and imperial units. Used for drug dosing in clinical practice.
CURB-65 score calculatorCalculate the CURB-65 pneumonia severity score. Tick five clinical criteria to get a score from 0 to 5 with low, moderate, or high severity band.
Mean arterial pressure calculatorCalculate mean arterial pressure from systolic and diastolic readings. Colour-coded status against the 60 mmHg perfusion threshold.
Paediatric fluid maintenance calculatorCalculate paediatric maintenance fluid requirements using the Holliday-Segar method. Enter weight in kg to get ml/hour and ml/24 hours with a full weight-band breakdown.
Wells score calculatorCalculate the Wells score for DVT or pulmonary embolism probability. Toggle between DVT and PE modes. Score with likelihood band — DVT unlikely/likely or PE unlikely/likely.
Age calculatorCalculate your exact age in years, months, and days from your date of birth. Also: find the difference between any two dates.
Temperature converterConvert between Celsius, Fahrenheit, Kelvin, and Rankine instantly. Type in any field and all others update live.
Length converterConvert between metric, imperial, and nautical length units instantly. Millimetres to miles and everything in between.
Weight converterConvert between metric and imperial weight units including stone, pounds, ounces, tonnes, and tons. Type in any field to update all others.
Working days calculatorCount working days between two dates, or find a date that is N working days from a start date. Excludes weekends and public holidays for England & Wales, Scotland, or the US.
Data storage converterConvert between bytes, kilobytes, megabytes, gigabytes and more. Shows both decimal (SI) and binary (IEC) values — and explains why they differ.
Reading time calculatorPaste any text to see its word count and estimated reading time. Adjust for slow, average, or fast readers.
Grade percentage calculatorConvert marks to a percentage, or work out the marks you need for a target grade. Includes UK and US grade boundary reference tables.
Cable size calculatorFind the right cable for any load and distance. Checks CCC and volt drop together. 1.5mm² to 185mm², all installation methods.
Volt drop calculatorCalculate voltage drop on a cable run. Single and three-phase. BS 7671 pass/fail limits with amber warning zone.
Max Zs tablesMaximum earth fault loop impedance by device type and rating. MCBs, BS 88 and BS 3036 fuses. BS 7671 18th Edition Amendment 2.
Amps / kVA converterConvert between amps and kVA for single and three-phase supplies. Standard UK voltage presets included.
Adiabatic equation calculatorCheck a cable can withstand fault current before the protective device disconnects. S² = I²t / k². BS 7671 k values included.
Safe isolation procedureStep-by-step HSE GS38 safe isolation checklist. Each stage locks until confirmed. Single and three-phase.
VAT calculatorAdd or remove VAT from any amount. UK rates: 20%, 5%, and 0%.
Stamp duty calculatorCalculate stamp duty, LBTT, or LTT on a property purchase in England & Northern Ireland, Scotland, or Wales. First-time buyer and additional property rates included.
State sales tax calculatorCalculate US sales tax for any state. Enter a price, select a state and item type, and add a local rate if needed. All 50 states plus D.C.
Compound interest calculatorCalculate how your money grows over time with compound interest. Enter a starting amount, optional monthly contribution, interest rate, and term to see your final balance and a year-by-year growth table.
Loan repayment calculatorCalculate your monthly repayment, total interest, and full repayment schedule for any fixed-rate loan. Works for personal loans, car finance, and more.
Profit margin calculatorCalculate gross, operating, and net profit margin from revenue and costs. Includes reverse mode — enter a target margin to find the required price or cost.
Redundancy pay calculatorCalculate your statutory redundancy pay entitlement based on age, years of service, and weekly pay. Includes year-by-year age-band breakdown and the £30,000 tax-free threshold. UK 2026/27 rates.
PCP & HP car finance calculatorCalculate monthly payments for PCP or HP car finance. Includes a GMFV estimator with slider, mileage overage estimate, and a full cost breakdown.
Savings goal calculatorFind out how much you need to save each month to reach any financial goal. Enter your target amount, timeframe, current savings, and interest rate to get your monthly figure.
£100k / 60% tax trap calculatorSee how the personal allowance taper creates an effective 60% tax rate between £100,000 and £125,140 — and calculate how much pension contribution would eliminate the trap for your income.
Salary calculator (UK)Calculate your exact UK take-home pay including tax, NI, pension and benefits.
Salary calculator (US)Calculate your US take-home pay. Federal income tax, Social Security, Medicare, and state tax for all 50 states. 2024 and 2025 tax years.
Salary calculator (IN)Calculate your Indian income tax and take-home pay under the new and old tax regimes for FY 2026-27. See which regime saves you more.
Salary calculator (AU)Calculate your Australian take-home pay including PAYG income tax, Medicare levy, superannuation, and optional HECS/HELP repayments. Weekly, fortnightly, monthly, and annual figures.
Marriage allowance calculatorCheck whether you qualify for the UK marriage allowance, see your annual saving of up to £252, and calculate how much you could reclaim by backdating up to four years.
Mortgage overpayment vs ISA calculatorSee whether overpaying your mortgage or investing in an ISA builds wealth faster — and find the crossover point where your ISA pot matches your remaining balance.
Salary calculator (CA)Calculate your Canadian take-home pay. Federal and provincial income tax, CPP, and Employment Insurance. All 13 provinces and territories. 2024 and 2025 tax years.
Pension carry-forward calculatorCalculate how much unused pension annual allowance you can carry forward from the last three tax years, and find the maximum contribution you can make this year with full tax relief.
Mortgage calculatorCalculate your monthly mortgage repayment, total interest, and stamp duty.
Equity release calculatorSee how compound interest grows your equity release debt over time. Enter each drawdown, rate and date to project the true cost.
Equity release amount calculatorEstimate how much equity you could release based on your age and property value, using an indicative UK loan-to-value table.
Bill splitterSplit a restaurant bill between friends, with custom shares for anyone who wants a different amount.
Sleep cycle calculatorFind the best time to go to sleep or wake up based on 90-minute sleep cycles. Adjustable cycle length and fall-asleep offset.
Running pace calculatorCalculate your running pace, finish time, or distance. Enter any two values and get the third instantly. Switch between kilometres and miles.
Alcohol units calculatorCalculate the number of units in your drinks. Add each drink to see a running total against the NHS 14-unit weekly guideline.
BMR calculatorCalculate your basal metabolic rate and daily calorie needs across five activity levels.
Solar panel savings calculatorEstimate how much electricity your solar panels would generate and how much you could save on your bills. Covers 30+ cities globally with irradiance data from PVGIS.
BTU calculatorCalculate the BTU and kW heating output needed for any room. Enter dimensions, insulation quality, external walls, floor type, and number of radiators.
Paint calculatorCalculate how much paint you need for a room. Enter dimensions, paint type, and number of coats — deduct doors and windows for an accurate result.
Tile calculatorCalculate how many tiles you need for a floor or wall. Enter room dimensions or area, tile size, and wastage percentage to get tiles and boxes needed.
Ratio calculatorSimplify a ratio to its lowest terms, or scale it to a target total.
Random number generatorGenerate random numbers, roll dice with standard notation, flip coins, or draw cards — all using cryptographically secure randomness, with a results history.
Statistics calculatorEnter a list of numbers to get count, sum, mean, median, mode, range, variance and standard deviation.
Statistics outlier calculatorPaste any data — numbers mixed with text are fine. Outliers are detected automatically using the IQR method. Adjust sensitivity with a slider, then get mean, median, mode, range, standard deviation, and more on the cleaned dataset.
Radar / spider chart generatorCreate a radar or spider chart with up to 12 named axes. Enter labels and values to visualise any data set instantly.
Equation solverSolve linear, quadratic and simultaneous equations.
Prime factorisation calculatorFind the prime factors of one or two numbers, with HCF and LCM when two numbers are entered.
Dog feeding calculatorCalculate how many calories and grams of food your dog needs each day. Enter breed, age, weight, activity level, and food type for a personalised daily feeding recommendation.
Meeting cost calculatorFind out what your meetings actually cost. Enter attendees, salary, and duration to see the real price of time in a room.
Earned value calculatorCalculate EVM metrics including CPI, SPI, EAC, ETC, and VAC. Traffic-light status, plain-English interpretation, and one-click copy for status reports.
Lottery odds calculatorSee your real odds of winning the jackpot on UK Lotto, Thunderball, EuroMillions, Powerball, and Mega Millions — and what you'd spend to get there.
Probability scenariosReal odds for the things people actually wonder about — royal flushes, lightning strikes, the birthday paradox, and more.
Drake equationExplore how many intelligent civilisations might exist in our galaxy right now. Adjust seven sliders and watch the answer swing from zero to millions.
Schengen day trackerTrack your 90-day allowance in the Schengen Area. Enter past trips and a planned visit to see days used, days remaining, and whether your next trip is allowed.
MPG calculatorConvert between UK MPG, US MPG and L/100km from a fill-up or a known figure, then calculate the cost of any journey based on your fuel efficiency and fuel price.
EV tariff comparison calculatorCompare EV tariff vs flat-rate electricity costs, with optional petrol comparison. Find your annual saving and break-even mileage.
Base64 encoder / decoderEncode plain text to Base64 or decode Base64 back to text. Runs entirely in your browser — nothing is sent to any server.
Unix timestamp converterConvert Unix timestamps to human-readable dates and times, or any date back to a Unix timestamp. Supports seconds and milliseconds. Shows current timestamp live.
URL encoder / decoderEncode special characters in a URL or query string, or decode a percent-encoded URL back to readable text. Runs entirely in your browser.
Regex testerTest regular expressions against sample text. Live match highlighting, captured group display, plain-English pattern explainer, replace mode, and 20+ global presets.
Cron expression parserParse a cron expression into plain English and see the next 5 run times. Or build a cron string from plain-language presets.
IP & subnet calculatorEnter any IP address in CIDR notation to get network address, broadcast, usable host range, subnet mask, wildcard mask, and a live bit-map. Three modes: CIDR lookup, IP range to CIDR, and subnet division.
Overtime calculatorCalculate gross pay for shifts with overtime. Enter your hourly rate, regular and overtime hours, and choose your overtime multiplier to see your total pay.
Billable time calculatorTrack session time and calculate your charge. Set your rate, log start and finish, handle rounding and downtime.