Knowledge, tips & tutorials about our calculators
Anyone working with three-phase power – on construction sites, in workshops or when planning industrial systems – needs the formula P = √3 × U × I × cos φ. Our calculator handles all the ...
Read more
Size circuit breakers correctly: rated current, trip curve B/C/D, cable check per standards.Step by StepEnter your values in the input fieldsClick calculate to see res...
Read more
Calculate reactive power compensation: improve power factor, size capacitors, reduce current.Step by StepEnter your values in the input fieldsClick calculate to see re...
Read more
Calculate grounding resistance for rod, ring and plate electrodes per IEC standards. With touch voltage check.Step by StepEnter your values in the input fieldsClick ca...
Read more
Calculate transformer: turns ratio N1/N2, primary/secondary current, power loss and core cross-section.Step by StepEnter your values in the input fieldsClick calculate...
Read more
Convert salary to hourly rate: monthly salary, annual salary and hourly wage comparison. With minimum wage check.Step by StepEnter your values in the input fieldsClick...
Read more
Calculate heating costs and compare energy sources: gas, oil, district heating, heat pump, pellets. With CO2 emissions.Step by StepEnter your values in the input fields...
Read more
Calculate rent per square metre: cold and warm rent per m², apartment comparison, annual rent.Step by StepEnter your values in the input fieldsClick calculate to see ...
Read more
Calculate grade point average: simple and weighted average, median, best and worst grade.Step by StepEnter your values in the input fieldsClick calculate to see result...
Read more
Calculate due date using Naegele rule: expected delivery date, current pregnancy week, trimester, maternity leave.Step by StepEnter your values in the input fieldsClic...
Read more
Is the voltage drop in my 20 m cable still within limits? The voltage drop calculator checks compliance with the DIN VDE 0100-520 3% limit and shows the correct cable length.
Read more
Which cable cross-section continuously carries 16 A when embedded in plaster? The cable sizing calculator determines the required cross-section per DIN VDE 0298-4, including installation correction factors.
Read more
The umrechner.online team wishes you a healthy and successful 2026! Find out what's in store this year and how you can help shape our free calculators.
Read more
The umrechner.online team wishes you a Merry Christmas! Discover our practical calculators for holiday cooking, baking, and family visits.
Read more
We have expanded our platform: all converters and calculators are now available in 7 languages.
Read more
Discover over 79 free online calculators and converters for everyday life, work, and hobbies. From unit conversion to practical calculators — precise, fast, and available in 5 languages.
Read more
Why does red + green = yellow on a screen, but a muddy colour when painting? The colour mixing simulator shows both principles with a live preview and explains the difference.
Read more
Everything sharp from 1 m to infinity — how is that done? The hyperfocal distance calculator shows the magic focus distance for any camera-lens-aperture combination.
Read more
How many business cards or flyers fit on a B1 press sheet? The imposition calculator optimises sheet layout and shows how much paper and money you save by choosing the right orientation.
Read more
Screen colour not reproducing correctly in print? The colour converter translates between RGB, CMYK, HEX, LAB, and spot colours — with an explanation of colour spaces and gamut limits.
Read more
Tyre pressure in PSI, blood pressure in mmHg, hydraulic pressure in bar — the pressure converter handles all pressure units and explains what they mean for everyday life and engineering.
Read more
Speed limit 130 km/h in mph for driving abroad, wind speed in m/s, or ship speed in knots — the speed converter switches between all units instantly.
Read more
US recipe in cups, bathtub in litres, heating oil tank in m³ — the volume converter handles all units and makes recipes, container sizes, and international specifications directly comparable.
Read more
How many football pitches fit in a hectare, and what is an acre? The area converter converts all area units — from mm² to km², and from metric to imperial.
Read more
How large is a 2480×3508 pixel image when printed at 300 DPI? The pixel DPI calculator converts pixels to centimetres (and back) — essential before sending any print job.
Read more
The time clock shows 7.83 h — but what time is that? The industrial minutes calculator converts decimal time to hours:minutes, essential for payroll and time tracking systems.
Read more
VW Golf 110 PS or BMW M3 510 PS — how many kW is that? The kW to HP converter delivers both units instantly and explains the difference between metric and imperial horsepower.
Read more
Sale, bulk discount, or tiered pricing — the discount calculator instantly shows what an item actually costs after the deduction and how much you save. Includes pitfalls of stacked discounts.
Read more
Nm³/h or Nl/min — what does your flow meter or compressor data sheet show? This converter quickly and accurately converts all standardised gas flow units.
Read more
What nominal size does a gas pipe need when the boiler and cooker are running simultaneously? The gas pipe sizing calculator determines the required DN size per DVGW TRGI.
Read more
Which pipe is right for a heating circuit or a new drinking water line? The pipe sizing calculator determines the optimal internal diameter based on flow rate and flow velocity.
Read more
How long does an 11 kg propane cylinder last on the grill, and what does a heating season cost with natural gas? The gas consumption calculator delivers accurate runtimes and cost estimates.
Read more
Too little pressure at the gas burner or boiler? The pressure drop calculator checks using the Darcy-Weisbach equation whether your gas pipe is correctly sized — before the installer arrives.
Read more
Normal cubic metres or operating cubic metres — which applies to your gas boiler? This calculator converts gas flow between standard and operating conditions, with calorific value calculation for natural gas.
Read more
What cable cross-section is required for a 32 A EV wallbox or a 16 A cooker circuit? The cable sizing calculator determines the minimum cross-section per DIN VDE 0100 and checks the voltage drop.
Read more
Calculate active, apparent, and reactive power. What is the power factor (cos φ) and why do industrial customers pay for reactive power? Includes single-phase and three-phase examples.
Read more
Calculate magnetic energy and inductive reactance for a given inductance. Applications in switching power supplies, filters, and motors explained.
Read more
Calculate capacitor charge, stored energy and discharge time constant. Applications in flash units, power supplies and motor starting.
Read more
Calculate resistors in series and parallel. With a colour code decoder for resistor bands and practical examples from electronics.
Read more
Convert time units quickly: seconds to hours, milliseconds to minutes, days to weeks. With the leap year special case and practical examples.
Read more
Understand exchange rates and convert currencies – for travel, online shopping and international transfers. With tips on optimising currency exchange.
Read more
Convert Celsius to Fahrenheit and Kelvin – with the most important reference points and memory aids for everyday use and science.
Read more
How does cooking time change when doubling or halving the quantity? Rules of thumb for roasting, baking and cooking – with tips on core temperature and oven types.
Read more
Convert baking temperatures between conventional (top/bottom heat), fan/convection and gas marks. With a complete temperature table and tips for different baked goods.
Read more
How do you scale a recipe from 4 to 6 or 10 servings? Adjust all ingredient quantities automatically – with special rules for baking recipes.
Read more
Convert tyre pressure between bar, PSI and kPa. Correct values for cars, motorcycles, bicycles and SUVs – and what over- or under-inflation means.
Read more
Calculate braking distance at different speeds – with reaction distance and total stopping distance. Why braking distance grows quadratically with speed.
Read more
Calculate your daily requirements for protein, carbohydrates and fat – for muscle building, weight loss or maintenance. With calorie distribution breakdown.
Read more
Calculate mixing ratios for 2-stroke fuel, paint dilution, fertiliser and chemicals. Explained using the mixing cross method and the ratio approach.
Read more
Mixing concrete yourself – how much cement, sand and gravel for which strength class? With mixing ratios and quantity calculator for your project.
Read more
Calculate electricity savings and payback time for LED bulbs. Comparison with incandescent and energy-saving bulbs – with real figures for your household.
Read more
Calculate electricity costs for individual appliances: formula, annual consumption and savings potential. With reference values for fridge, washing machine, TV and heating.
Read more
Calculate loan repayments for an annuity loan: monthly payment, amortisation schedule and total interest. For property, car and consumer loans with real numbers.
Read more
Calculate compound interest: how does your capital grow at 3%, 5% or 7%? With final capital calculation, investment duration and comparison with and without compounding.
Read more
Calculate the arithmetic mean, median and mode from a set of numbers. With an explanation of when each measure is the most useful.
Read more
Calculate the perimeter of a circle, rectangle, triangle and square – with formulas and practical examples for fencing, borders, sports facilities and school assignments.
Read more
Pythagoras a² + b² = c²: calculate the hypotenuse or a leg of a right triangle. With practical examples for roof pitches, ladders and distances.
Read more
Calculate mechanical work W = F×s, potential energy E = mgh and kinetic energy E = ½mv². Guide with concrete examples from everyday physics and engineering.
Read more
Calculate acceleration using a = (v₂−v₁)/t or a = F/m. Guide with concrete examples covering 0–100 sprints, braking distances and physics problems.
Read more
Calculate force using Newton's second law: F = m × a. Guide with practical examples covering weight force, traction and braking for physics and engineering.
Read more
Calculate the volume of a cube, cylinder, sphere, pyramid and cone – with the correct formulas and practical examples for construction, DIY and school.
Read more
Calculate your daily calorie needs: basal metabolic rate using Harris-Benedict × PAL factor. Guide with concrete examples for weight management and sports nutrition.
Read more
Calculate petrol costs for any journey: distance × consumption × price. With a guide on measuring your own fuel consumption and calculating cost per kilometre.
Read more
Calculate the area of a circle, rectangle, triangle and trapezoid – with the correct formulas and practical examples for home renovation, garden and trade.
Read more
Calculate density using ρ = m/V: determine the mass, volume or density of any object. With practical examples on buoyancy, material testing and physics problems.
Read more
Calculate speed from distance and time using v = s/t: unit conversion km/h ↔ m/s with concrete examples from everyday life and physics.
Read more
Solve proportion problems: direct (more = more) or inverse (more = less) – step by step with everyday examples from cooking, work and travel.
Read more
Percentage calculations made easy: all three basic types with formulas and everyday examples – from discount calculations to interest.
Read more
Calculate VAT quickly: net to gross (19% or 7%) or the reverse. With an explanation of tax rates and real-world use cases.
Read more
What's left of your gross salary? Calculate net pay with tax class, church tax, child allowance and federal state – updated for 2025.
Read more
Calculate parcel weight and volumetric weight for all major carriers. Avoid expensive surprises when shipping.
Read more
Calculate the weight of materials from volume and density. Includes a density table for metals, wood types, building materials and plastics.
Read more
How much should you ideally weigh? The Broca formula, WHtR and BMI explained – differences, limitations and what really matters.
Read more
Convert precious metal weights between grams, troy ounces and karats. For gold, silver and platinum – with gold content by karat marking.
Read more
Convert American recipe measurements to ml and grams: cups, tablespoons, teaspoons. Includes ingredient-specific weight tables and key differences.
Read more
Calculate storm distance from the gap between lightning and thunder – a guide with the formula, safety rules and practical examples for walkers and athletes.
Read more
Convert steps to kilometers – a guide covering step length calculation, the 10,000-step goal and practical examples for accurate fitness tracking.
Read more
Calculate calories burned walking and running – a guide with the MET formula, practical examples and a comparison of different speeds and body weights.
Read more
Calculate and compare CO2 emissions for every mode of transport – a guide with emission factors, the RFI factor and practical examples for popular routes.
Read more
Calculate pressure loss in pipes for heating and plumbing systems – a guide using the Darcy-Weisbach formula with practical examples for different pipe materials.
Read more
Estimate driving distance from a straight-line measurement – a guide with detour factors for different terrain types and examples of well-known routes.
Read more
Calculate fence length, number of posts and material requirements for any plot – a guide with practical examples for gardens, paddocks and driveways.
Read more
Calculate the maximum cable length for safe electrical installations – a guide with the formula, DIN VDE 0100 and practical examples for sockets and wall boxes.
Read more
Calculate tile quantities correctly – a guide covering wastage, packs needed and practical examples for bathrooms, kitchens and living rooms.
Read more
Calculate the right amount of paint for any room – a guide covering coverage rates, tin sizes and practical examples for walls, ceilings and wood.
Read more
Ohm's Law explained: calculate voltage, current, resistance and power – a guide with formulas, memory aids and concrete electronics examples.
Read more
Calculate voltage drop in electrical cables to DIN VDE 0100 – a guide with the formula and practical examples for domestic and garden installations.
Read more
Calculate wallpaper rolls for any room – a guide covering waste allowance, pattern repeat and practical examples for living rooms, bedrooms and hallways.
Read more
Convert screen diagonals between inches and centimeters – with concrete TV and monitor sizes and recommendations for the right viewing distance.
Read more
Convert sports distances between meters, kilometers, miles and yards – ideal for runners, cyclists and triathletes in training and competition.
Read more
Convert nautical miles to kilometers and land miles – a guide with practical examples from sailing trips, shipping and aviation.
Read more
Convert travel distances between kilometers and miles – perfect for US road trips, rental cars, navigation systems and international travel planning.
Read more
Convert height between centimeters and feet/inches – ideal for US travel, dating apps, sports profiles and international documents.
Read more
Convert lengths between meters, centimeters, feet, inches and miles – a guide with examples from construction projects, travel and sport.
Read more
Convert weights between kilograms, pounds, ounces and stone – a practical guide with real-world examples from cooking, shipping and fitness.
Read more
