Blog
Guides to the math behind the tools — readability formulas, pricing your work, sizing a build, and planning a game world.
Your laser-cut wholesale price might be below cost — here is the markup that fixes it
Wholesale is usually shown as 60% of retail, which quietly makes it a function of your retail markup rather than a margin you set. Below a 67% markup that number drops under your production cost, and here is the arithmetic that proves it.
What does "28mm scale" actually divide by? The hidden ratio behind heroic-scale terrain
Six feet divided by 28 millimetres is 1:65, but every terrain converter says 28mm is 1:60. The gap is a measurement convention, not a rounding error — and it decides whether your buildings sit right next to your miniatures.
Scattergories over a long game night: repeated categories, sticky settings, and a clock that can run slow
A single Scattergories round is easy to set up fairly. Ten rounds in a row is a different problem — the category bank runs shallower than you think, the tool remembers last week's settings, and the countdown counts ticks rather than seconds.
From "1 in 12 packs" to real odds: translating official pull-rate sheets
Games publish pull rates in half a dozen incompatible formats — guaranteed slots, upgrade rates, per-card percentages. How to convert each one into the calculator's two inputs, and when the independent-pack model stops applying.
Wiring several LED strip runs to one power supply
How the load of parallel strip runs stacks onto a single supply, why each run still keeps its own voltage-drop budget, and when the calculator is really telling you to split the job across two supplies.
Will your solar panels actually keep up with your daily load?
Runtime and recharge time are two numbers a power-station calculator reports separately — but whether you can run indefinitely depends on daily solar harvest versus daily draw, which turns on sun-hours the tool never asks for.
TDP isn't watts drawn: reading a PC parts list into real power
The CPU and GPU numbers you copy off a spec sheet are thermal ratings, not measured draw — the gap runs both ways. Plus what the calculator's fixed per-component figures assume, and the second safety margin it adds on top of yours.
Running low- and high-gravity worlds: turning surface g into table rules
Once you have picked a planet's surface gravity, how do you actually play it? Concrete rules for jump distance, fall damage, carrying capacity, movement, and long-term strain — all keyed to the one number that drives them.
How to choose a RAID level: matching redundancy to how much you can lose
RAID 0, 1, 5, 6, and 10 make different trades between usable space, fault tolerance, rebuild risk, and performance. A practical decision guide for picking the level that fits your drive count, capacity, and tolerance for downtime.
The wedding bar budget: turning a drink count into what you actually spend
A shopping list of cases and bottles is only half the job. How bar format, buy-back policies, signature cocktails, and where you buy turn that quantity into a real cost — and how to trim it without leaving guests dry.
Why a cheap KDP paperback can earn you nothing: the print-cost floor explained
Amazon pays paperback royalty as 60% of price minus a print cost that rises with page count. Below a break-even list price the royalty hits zero — here is how to find that floor before you publish.
Dye lots, deductions, and the waste buffer: ordering wallpaper you won't have to reorder
Getting the roll count right is only half the wallpaper order. The other half is buying from one dye lot, setting a sane waste buffer, and deducting doors and windows without shorting yourself.
When to bump the numbers: adjusting party food quantities for your actual event
Standard per-person food figures assume an average event. A lunch, a drinking crowd, an all-buffet spread, or a long cocktail party each pull the numbers in a different direction — here is how to adjust.
Pick the odds first: setting dice target numbers backward from the success rate you want
Most GMs choose a target number and hope it feels fair. Reverse the process — decide the success rate you want, then read the target off the curve — and difficulty stops being a guess.
Working backward from take-home: how to price an Etsy item to a target margin
Knowing what Etsy takes is only half the job. Here is how to run the fee math in reverse — start from the margin you need, and find the price that gets you there.
From board count to lumber order: waste, cuts, and choosing the right board length
A calculator tells you the exact boards a deck needs. The lumberyard order is a different number — here is how waste factor, seam placement, and board length turn one into the other.
Choosing soap oils: balancing hardness, lather, and conditioning
Why cold-process recipes lean on olive, coconut, and castor oil, what each one contributes to a finished bar, and how the blend — not just the lye math — decides whether your soap is hard, bubbly, and gentle.
French drain design: slope, depth, and where the water actually goes
Before you calculate gravel and pipe, get the design right — minimum slope, how deep to dig, which way the perforations face, and where the outlet daylights — because a perfectly built drain to the wrong place still floods.
Why your EV draws more kWh than its battery holds — charging losses explained
The two numbers that make EV running-cost estimates wrong: charging losses (you pay for more energy than reaches the battery) and real-world efficiency (mi/kWh swings with speed, cold, and terrain). Here is how each one moves your cost per mile.
How to run Pictionary without the argument over who wrote the words
The board game works until someone recognises their own clue or picks something impossible to draw. A random word generator with a built-in timer fixes both problems and keeps rounds moving.