What's new

New water bill calculator — work out your water and sewage bill from household size or a meter reading, with standing charge, tiered tariffs and a per-person usage comparison against everyone else. Water Bill Calculator →

New heating cost calculator — compare the yearly and monthly cost of 7 heat sources (gas, heat pump, electricity, oil, pellet, wood, district heating) for the same home on one chart; enter floor area and building class or your usage directly in kWh/GJ. Heating Cost Calculator →

New weight converter — grams, kilograms, decagrams, tonnes, ounces, pounds and stone, all at once with exact factors; dedicated pages for popular conversions (kg to lbs, grams to ounces, kg to stone) with common-value tables. Weight converter →

Global currency support — a currency picker in the site header (25 currencies, auto-detected from your country), currency symbols on money inputs and results across all finance calculators, a quick per-calculator currency switch, and an indicative "≈ in your currency" conversion based on daily ECB rates.

New Conversion category with a length converter — 9 units (mm to nautical miles) with exact factors, all results at once, plus 22 dedicated pages for popular conversions (like cm to feet) with common-value tables. Length converter →

The "Related calculators" section now shows the top picks plus an "All in this category" tile — you find what you need faster instead of scrolling the whole list.

Fixed calculator page URLs so they show up better in Google results.

New speed calculator — solve for speed, distance or time using v = d/t and instantly read the result in every unit: km/h, mph, m/s, knots and ft/s (plus km, miles, metres, nautical miles). Speed Calculator →

New fuel economy calculator — enter one value and get all four units at once: L/100km, MPG (US), MPG (UK/imperial) and km/L, with a clear explanation of why UK MPG runs higher than US MPG. Fuel Economy Calculator — MPG, L/100km & km/L Converter →

New fuel cost calculator — distance, fuel economy (L/100km, km/L, US & UK MPG) and price per liter or gallon; round trips, split cost per passenger, a price-sensitivity chart and how your consumption compares to others. Fuel Cost Calculator — Trip & Commute Cost →

New electricity cost & usage calculator — cost of a single appliance or your whole bill, with day/night multi-zone tariffs, VAT, standing charge and a CO2 footprint, plus how your usage and cost compare to others. Electricity Cost Calculator →

New GCD & LCM calculator (also GCF/HCF) — both values at once for any set of numbers, with the Euclidean algorithm steps and full handling of zero and negative inputs. GCD & LCM Calculator →

New rounding calculator — round to decimal places, the nearest ten/hundred/thousand, or significant figures, in five modes (half-up, banker's, ceiling, floor, truncate), showing what every mode would give. Accurate even on the classic traps (2.675 → 2.68). Rounding Calculator →

New exponent calculator — computes aᵇ for integer, negative, fractional and zero exponents (including 0⁰), showing the step-by-step expansion, the root equivalence and adjustable decimal precision. Exponent Calculator →

New quadratic equation calculator — get the discriminant, real and complex roots, vertex and axis of symmetry, Vieta's formulas, and vertex/factored form, with an interactive parabola graph marking the vertex and roots. Quadratic Equation Calculator →

New VAT calculator — add or remove VAT (net↔gross) and see the tax on its own, with ready rate presets for the UK, EU and beyond, plus a chart of the tax share of the price. VAT Calculator →

New sleep calculator — tells you when to go to bed or wake up in sync with your sleep cycles, with adjustable fall-asleep time and cycle length, a night timeline, and a comparison of your sleep length against others. Sleep Cycle Calculator →

Fraction results now render as a clean stacked fraction (numerator over a bar over denominator) — in the fraction calculator and the ratio calculator (convert mode).

A new way to see how you compare — a percentile strip with the median, quartiles and your position (starting with the age calculator). Age Calculator →

Davided is now easier to find in search engines and AI assistants (ChatGPT, Perplexity, Gemini) — we added a site index for AI models (llms.txt) and opened access to AI crawlers.

New average calculator — mean, median, mode, range, sum, min and max from a single list at once, plus a weighted-average option; paste numbers any way you like (space, comma, new line) and see a distribution histogram. Mean, Median, Mode & Range Calculator →

New ratio calculator — simplify a ratio, solve a proportion for the missing value (a:b=c:x), scale it, split an amount by a ratio (e.g. 1200 in 2:3:5), and convert it to a percentage or fraction, all in one place. Ratio Calculator →

New square root calculator — square, cube and any nth root: decimal value with adjustable precision, simplified radical form (√72 = 6√2) and a power check, all in one place. Square Root Calculator →

New standard deviation calculator — get the sample (n−1) and population (n) standard deviation and variance, plus the mean, sum and standard error of the mean, from a list of any length, with optional step-by-step working. Standard Deviation Calculator →

The "how you compare" hero tile on the homepage now keeps a constant width across categories — no more shrinking on short values or jumping as it rotates.

New fraction calculator — add, subtract, multiply and divide, with the result reduced to lowest terms and shown as a mixed number and a decimal. Handles negatives and mixed-number input. Fraction Calculator →

New ideal weight calculator — five named formulas at once (Devine, Robinson, Miller, Hamwi, Broca) plus the healthy BMI range, split by sex and body frame, with a comparison of your weight against other users. Ideal Weight Calculator →

New running pace calculator — get pace, speed and time in min/km or min/mile, see your per-km/mile splits and predicted finish times for 5K, 10K, half marathon and marathon, and compare your result with other runners. Running Pace Calculator →

New water intake calculator — how much to drink daily from body weight, activity, climate and pregnancy/breastfeeding; two methods (ml/kg and tiered), a drinking schedule, a unit switch (L/ml/oz/cups) and how you compare to others. Water Intake Calculator →

New "What's new" page — a public, dated changelog of the site, linked in the footer.

Refreshed home page plus category and calculator headers — an animated headline whose keyword changes per category and an interactive background showing a "distribution" of results; on the home page a live "you vs others" preview that links straight to the calculator. The hero is now visible on mobile too.

Mortgage calculator — full PITI payment (tax and insurance included), PMI with its drop-off marked on the chart, presets for 10 countries. Mortgage Calculator →

Retirement savings calculator — capital in nominal and today's money, a retirement goal computed two ways and the contribution that closes the gap. Retirement Savings Calculator →

50/30/20 budget calculator — splits income into needs, wants and savings, plus a comparison with your real spending. 50/30/20 Budget Calculator →

Body fat calculator — three methods at once (US Navy, RFM, BMI) from a single set of measurements, a category scale and body composition. Body Fat Calculator →

The Polish gross–net calculator now covers all contract types: mandate, specific-task and B2B (3 tax forms) — with a take-home comparison bar between contracts and variable monthly pay.

"You vs others" comparisons gained group switches — see your result against people of the same sex, the same age or from the same country.

Calorie calculator (TDEE/BMR) — three formulas, macros, calorie goals and a weight forecast; supports pregnancy and breastfeeding. Calorie Calculator — TDEE & BMR →

Days between dates calculator — working days and weekends, add/subtract days and a timeline of the whole period. Days Between Dates Calculator →

Discount calculator — three modes, a cascade of up to 4 discounts and a chart showing what you really pay. Discount Calculator →

Due date calculator — four methods (last period, conception, ultrasound, IVF) on a single page. Due Date Calculator →

Ovulation and fertile days calculator — fertile window, a cycle timeline with conception probability and a forecast up to 3 cycles. Ovulation Calculator →

Polish gross–net salary calculator — employment contract, tax reliefs, PPK and a 12-month table with the tax threshold (Polish only).

Use counters, a "helpful" button and correction reports on every calculator.

About, Contact and Privacy policy pages in three languages, plus a sitemap for search engines.

Davided goes live at davided.pro: five calculators (BMI, percentage, age, compound interest, loan with overpayment) with live results, in three languages (EN/PL/ES).

Anonymous "you vs others" comparisons — a histogram with your percentile on many calculators.

Dark mode with a theme switch (system / light / dark).