Toys & collectibles · sourced numbers
The numbers behind collecting and selling cards.
Small calculators built from questions collectors keep asking in forums. Each one shows its formula, cites the page it came from and says what it leaves out.
Trading Card Count by Weight Calculator
Estimate a trading card count from weight, with a range and a calibrate-from-sample mode.
Trading Card Postage Calculator
USPS letter and large-envelope postage for mailing trading cards, with cards per price step.
Magnetic One-Touch Size Finder
Pick a magnetic one-touch holder size (pt) from a card thickness.
Card Collection Offer Calculator
Compare a dealer offer to selling a card collection on eBay after fees and costs.
ASW Calculator
Actual silver or gold weight from a coin's weight and fineness
Coin Density Test Calculator
Density from water displacement or weight under water, with an error range
Stamp Postage Combination Calculator
Every way your old stamps add up to the postage you need
Vinyl Record Shipping Weight Calculator
Total weight, billed pound and Media Mail price for a box of LPs
How these pages are sourced
Game formulas come from published rules and community wikis that we open and cite on each page, with the date we checked. Where a formula is not published, the page says so and asks you for the number instead of guessing. These tools are not affiliated with any game publisher, and game names appear only to describe what a calculator is for.
Collector tools · coins, stamps and records
The sums collectors keep redoing.
Fineness is not silver content, a drawer of old stamps never quite adds up, and ten LPs weigh whatever the box and sleeves make them. Each calculator here does one of those sums, shows its formula, and cites where the numbers come from.
Where these came from
Each tool answers a question collectors were asking in public threads: how to turn weight and fineness into actual silver weight, how to test a coin's density with water, how to make old stamps add up to a postage rate, and what a box of albums weighs. The pages work from numbers you enter, cite their sources, and say what they leave out. They are planning aids, not appraisals, and they are not affiliated with any mint, post office or forum.