15 Useful Online Calculators You Should Know About

Land drainage calculator

Use this calculator to work out the required pipe size per acre and also calculate any gradient fall. Courtesy of the University of Minnesota http://www.extension.umn.edu/agriculture/water/online-calculator/

Roof guttering flow calculator

Select the right gutter size for the amount of flow pouring off a pitched roof. FloPlast’s site gives calculation results for a single roof, hipped roof, valley and double valley roofs. http://www.floplast.co.uk/products-related/calculator?m=2

Gravity-fed pipe flow calculator

If you’re an engineer, then the Hazen-Williams formula will be familiar to you when calculating water velocity and discharge rate. If you’re not, you can work out the maths here. http://www.calctool.org/CALC/eng/civil/hazen-williams_g

Flow in pressurised pipe calculator

Another offering using the Hazen-Williams formula, this time for pressure loss over the entire length of a pipe. http://www.calctool.org/CALC/eng/civil/hazen-williams_p

Best online conversion tool

Convert almost anything on this too, from newtons to kg’s, degrees to minutes, parsecs to light years… it’s all here.

http://www.onlineconversion.com/

Scale conversion tool

Yes, this is a website on scale models, but their tool is simple and easy to use (and the rest of the site is interesting too!)

http://www.scalemodelersworld.com/online-scale-converter-tool.html

Map scale calculator

This useful web tool calculates distances on a map. All you need is a ruler and program in the map’s scale. https://rechneronline.de/scale/

Square footage calculator

If you need to work out the square feet of an area, this is the tool for you. It will also calculate in yards and metres, and work out the cost per square foot/yard/metre too. Another reason to use this tool is that it will work out circular areas, triangles, even a trapezoid area.

http://www.calculatorsoup.com/calculators/construction/square-footage-calculator.php

Concrete volume calculator

Another handy tool from Calculator Soup is this concrete volume calculator. It’s just as versatile as the square foot calculator with lots of shape options and will calculate the total cost too.

http://www.calculatorsoup.com/calculators/construction/concrete-calculator.php

Feet and inches length measurement calculator

You can mix ‘old school’ with metric with this handy calculator! Add 6 and 3/8ths of an inch to 8cm!

http://www.inchcalculator.com/

Measure pitch angle calculator

Handy pitch calculator with great visual spirit levels. You can also use this calculator on a phone or tablet, place it on the angle to directly measure pitch and angle. How handy is that!

http://www.blocklayer.com/roof-pitch.aspx

Bricks and mortar calculator

A quick and simple bricks calculator showing the number of bricks and how much mortar needed for a given wall area.

http://everydaycalculation.com/brick.php

Tiling and paving calculator

Work out how many square or rectangular tiles or slabs you need to cover an area.

http://www.online-calculators.co.uk/diy/tiling-paving.php

Pipe diameter calculator

Suitable for both liquid and gases, this tool will calculate the pipe size for the proposed flow rate. You can also use it for calculating velocity.

http://www.pipeflowcalculations.net/pipediameter.xhtml

Percentage calculator

This is our personal favourite! If you haven’t already got this one bookmarked, do it now.

http://www.percentagecalculator.co/

These are web based calculators provided free and in good faith by sites outside of Drainfast’s control. They’re not a substitute for rigorous ‘best practice’. Use these calculators wisely and always double-check the answers.