Why this site exists
Material estimating fails in two directions, and both cost money. Buy too much and you have three half-used buckets of tinted paint that nobody can return and no room needs. Buy too little and you discover it at 4pm on a Saturday, mid-roll, when the colour you carefully matched is now a different batch.
The web is full of calculators for this. Most of them share the same problem: they give you a single number with no explanation of where it came from, no indication of how much it could be off by, and no way to sanity-check it against what the guy at the hardware store just told you. When the number is wrong, you find out at the store, not on the screen.
EasyCalc is our attempt to do the opposite. Every tool on this site shows its arithmetic, states the assumptions it made, and tells you how much those assumptions are worth. The goal is not to be authoritative — it is to be checkable.
Who runs it
EasyCalc is an independent project, maintained under the pen name Hank. We publish under a first name rather than a full one because the calculators matter more than who happens to be maintaining them — but there is a real person behind them, and the contact page reaches him directly.
Day to day it is one DIYer and a small group of friends in the trades who sanity-check the numbers before they go live. It is not owned by, affiliated with, or funded by any paint, concrete, or flooring manufacturer or retailer. That independence is deliberate: a calculator funded by a supplier has a quiet incentive to round up.
Where our numbers come from
Every default you see in a calculator is traceable to a published source rather than a guess. Our reference points are:
- Coverage rates are taken from manufacturer technical data sheets for mainstream interior and exterior products, cross-checked against retail product labelling. Where coverage varies widely between brands, we show the range instead of a single figure.
- Waste factors come from trade practice, not theory. A 10% flooring waste allowance is standard for straight-lay rooms; diagonal layouts and rooms with many corners run higher. We expose the waste percentage as an input rather than hiding it, because it is the number most likely to be wrong for your specific room.
- Unit conversions and material densities use standard industry figures — for example, ready-mix concrete at approximately 150 lb per cubic foot, which is the basis of the 60 lb / 80 lb bag yields used by the concrete calculator.
- Bag and container sizes reflect what is actually stocked at major home improvement retailers, since an estimate expressed in units you cannot buy is useless.
How we test each calculator
Before a tool is published it goes through a fixed routine:
- Hand-checked arithmetic. We calculate a set of representative scenarios by hand and confirm the tool agrees.
- Boundary testing. Zero, very small, and very large inputs must not produce negative quantities, division errors, or nonsense like "0.0001 gallons".
- Real project comparison. Where possible we compare the output against the quantity actually used on a real job, and record the difference.
- Unit sanity. Every result is checked for correct units, since a square-foot figure reported as square metres is the most common and most expensive class of calculator bug.
When a discrepancy shows up in step 3, we publish it. Real-world consumption is messier than any formula, and pretending otherwise would make the tool less useful, not more.
What our estimates are not
Surface conditions move the number more than any formula can capture. Porous, patched, or previously unpainted surfaces absorb dramatically more paint. A subfloor that is out of level can push flooring waste far above the standard allowance. Colour changes across a wide spectrum routinely need a third coat. Our calculators tell you what the geometry demands; they cannot see your walls.
What we do not do
- We do not sell your data. There are no accounts, so there is very little to sell. See our privacy policy.
- We do not take payment to rank products. No manufacturer or retailer can pay for placement or for a favourable default value.
- We do not gate results. No email wall, no "sign up to see your full estimate". The number appears immediately.
- We do not pad estimates upward to make affiliate links more lucrative, because we do not run affiliate links.
Corrections and feedback
If a calculator gives you a number that looks wrong, we want to know. Reports of this kind are the single biggest source of improvement on this site, and several of our current defaults were changed because a visitor ran a real project and told us the result was off. Use the contact page — include your inputs and what you expected, and we will work through it.