Presents is a free calculator website for people planning a home renovation who would rather measure twice than pay twice.
Most expensive renovation mistakes are not design mistakes. They are arithmetic mistakes: a sofa two inches too deep for the doorway, wallpaper that runs out one strip before the end of the wall, a mirror that dwarfs the vanity, a ‘bargain’ appliance that costs more to run than it saved. Our calculators exist to catch those mistakes on screen, while they are still free to fix.
What our calculators do
Each tool on this site takes the measurements you already have — a room width, a wall height, a sleeper’s height, an energy bill — and applies the same planning rules that tradespeople and designers use: standard opening sizes for doors and windows, pattern-repeat allowances for wallpaper, the two-thirds rule for furniture against a wall, straight-line depreciation for appliances, and per-load energy costs for dryers. You get a straight answer in seconds, plus the reasoning behind it, so you can sanity-check the number instead of blindly trusting it.
How our content is made
Every calculator page is written and checked by a human planner before it is published. We test each tool with worked examples, write the guide that sits below it from real planning practice, and update pages when product sizes or energy prices change. Our articles are original, practical and deliberately short on fluff: if a page tells you to buy something, it first tells you how to measure whether you need it.
We are not a shop and we do not sell the products our calculators size. That independence is the point — a tool that does not earn commission on a bigger sofa has no reason to recommend one.
A note on accuracy
Our calculators are planning estimates, not quotes. They use standard sizes and sensible allowances, but every home has surprises behind its walls, and final measurements must always be confirmed on site before cutting, ordering or signing a contract. Energy prices, material costs and product dimensions change; check current local prices before you budget. For structural work, electrical work, plumbing and roofing, always consult a licensed professional.
Renovation will always involve judgement calls. Our job is to make sure the numbers those calls rest on are right.