Reference, charts & cost tools

Every chart, cost breakdown, dosing guide and comparison we publish, in one place. What makes these different from the usual reference pages is the same idea behind the whole site: each one adds the real cost per unit — the price per diaper, per page, per load, per spray — that plain charts leave out.

Size & spec charts

The reference tables people look up — each one adds the live cheapest cost per unit that plain charts leave out.

Diaper size chart Weight & age by size, plus the cheapest cost per diaper at each size.Battery sizes chart Dimensions, voltage and capacity — with the cheapest cost per cell.Trash bag size chart Gallons, dimensions and what fits, plus the cheapest cost per bag.Ziploc & storage bag sizes Snack to two-gallon dimensions, plus the cheapest cost per bag.Paper weight chart lb-to-GSM for bond, text, cover and index — and why GSM is the one that compares.Sheets in a ream of paper A ream is 500; a case is 5,000 — with the live cost per sheet.Sheets on a roll of toilet paper Regular to Super Mega, why the labels are marketing, plus cost per 100 sheets.Paper towels in a roll Sheets by roll size, select-a-size explained, plus cost per 100 sheets.

What things really cost

Cost breakdowns where the recurring items are measured from live prices and one-off or utility lines are clearly labelled as estimates.

Newborn cost per month Diapers measured live; formula, wipes and healthcare as US ranges.Cost of owning a cat (month) Food, litter and treats measured; vet and insurance as ranges.Cost of owning a dog (month) Food and treats measured; vet, insurance and grooming as ranges.Cost of owning a cat (year) The annual figure plus the first-year one-off.Cost of owning a dog (year) The annual figure plus the first-year one-off.Cost of a load of laundry Detergent measured live; water, energy and dryer as US ranges.Cost to run a dishwasher Detergent measured live; electricity and water as US ranges.How much printer ink costs The real cost per page, and why ink is so expensive.

What it costs to run

The kWh math behind everyday appliances — typical wattage and energy × the US-average electricity rate, so you can reprice any of them to your own bill.

How much electricity a TV uses ~50–200 W — cost per hour, month and year, plus standby.Cost to run a refrigerator ~1–2 kWh/day — how to read the EnergyGuide label and cut it.Cost to run an air conditioner Window 500–1,440 W — cost per hour, and window vs central.Cost to run a space heater 1,500 W ≈ 26¢/hour — why every electric heater costs the same.Cost to run a ceiling fan 15–90 W, pennies a day — far cheaper than AC.Cost to run a dehumidifier 300–700 W — how the humidistat setting drives the cost.Cost to run a dryer ~2–4 kWh/load — cost per load and year, electric vs gas.How much electricity a computer uses Laptop ~50 W to gaming PC 600 W — by type, plus sleep vs on.Cost to run a hot tub ~5–10 kWh/day of standby heat — why the cover matters most.Cost to charge a Tesla ~$10–$17 a full charge at home, ~4–5¢/mile — vs Supercharger and gas.Cost to charge an electric car Home vs public DC-fast, cost per mile, and the gas comparison.

How much to use

Almost everyone uses too much — these give the right amount and the cost per use, so a product lasts as long as it should.

How much laundry detergent By format and water hardness — overdosing doubles the cost per load.How much shampoo By hair length — you wash the scalp, not the lengths.How much conditioner Ends only, never the scalp — with the cost per use.How much sunscreen The shot-glass rule — most people under-apply badly.How much coffee per cup The right ratio by method, and the real cost per cup.Coffee ratio calculator Cups + strength → the exact grams and tablespoons, plus grounds-vs-K-Cup cost per cup.Paint calculator Room size → gallons needed and cost; a gallon covers ~350–400 sq ft.Mulch calculator Bed size + depth → cubic yards, bags and cost; a yard is 13.5 bags.How much to feed a dog The daily chart by weight, and the cost per day.

How long it lasts & when to replace

How long a bottle, tube or blade actually lasts — and when to swap it — with the cost per use behind the answer.

How long a bottle of perfume lasts Sprays by size, months by use, and the cost per spray.How to tell if a perfume is fake The price-per-ml test, with the real band for each designer house.How long perfume lasts on skin EDT vs EDP hours, priced to the real cost per hour worn.How long sunscreen lasts Shelf life, after opening, and per bottle in use.How long body wash lasts Per bottle in use, plus the cost per shower.How long a bar of soap lasts Weeks per bar, drying tricks that double it, and the cost per wash.How long a propane tank lasts Grill hours by BTU, how to check what’s left, and the cost per hour.How often to change your air filter Interval by filter type, what a clog costs, and the price per year.How long a tube of toothpaste lasts By size and dose, with the cost per brushing.How long deodorant lasts On your skin, in the stick, and on the shelf.How often to change oil The real interval, and the cost per quart.How often to replace razor blades Shaves per blade and the cost per shave.How often to replace a loofah Sooner than you think — and cheaper alternatives.How often to replace your toothbrush Every 3–4 months, and what a year of brushes costs.

Compare & decide

The tools and comparisons behind our one idea — real cost per unit — for the calls people actually make at the shelf.

What is unit price? How cost per unit works, and why the cheapest sticker rarely wins.Unit price calculator Compare any two pack sizes by cost per unit.Generic vs name brand The real store-brand savings by category, from tracked prices.Cloth vs disposable diapers The real cost compared — disposables priced live, cloth as an estimate.SPF 30 vs 50 The real difference (smaller than the number), and when 50 is worth it.Bar soap vs body wash Which is cheaper, cleaner and better for your skin.Liquid vs powder detergent Which cleans better, and which is cheaper per load.Dishwasher pods vs powder Which cleans best, which is cheapest per load.Best cat litter by type Clumping vs crystal vs lightweight, and the cheapest of each.Best diapers for newborns What actually matters, and the cheapest that deliver.Protein in a protein bar Typical grams, and the cost per gram of protein.How many diapers a newborn uses Per day, month and year — and what that costs.

What’s a good price?

The live good / typical / overpaying bands for each category, from the real cost-per-unit distribution — so you know a fair number before you shop.