Guides for people who measure things
Practical writing on shipping, dimensional weight, volume math, and the surprising amount of geometry hidden inside everyday decisions.
Dimensional Weight Explained: How FedEx, UPS, USPS, and DHL Calculate It
A clear, complete explanation of dimensional weight: what it is, why carriers charge it, and the exact formulas used by FedEx, UPS, USPS, and DHL in 2026.
How to Read a FedEx Shipping Label (And What the DIM Weight Means)
A field-by-field breakdown of a FedEx shipping label, including how to find the billed dimensional weight, service class, and zone, with a worked example.
UPS vs FedEx: Which Has Better Dimensional Weight Rules in 2026?
A side-by-side comparison of UPS and FedEx dimensional weight policies, divisors, minimum billable weights, and oversize fees — with guidance on which to choose.
International Shipping Dim Weight: Why the 5000 Divisor Matters
How the 5000 cm³/kg dimensional weight divisor became the international standard, why it's less aggressive than the US domestic divisor, and how to calculate it correctly.
How to Avoid Oversize Shipping Fees: The 165cm Rule
Oversize package surcharges add $50-$200 per shipment. Learn how to measure for length + girth, the 165cm and 108-inch thresholds, and how to avoid these fees through packaging design.
Girth in Shipping: What It Is and Why It Costs You Money
Girth is the distance around a package perpendicular to its longest side. Learn the formula, why carriers use it, and how to measure your boxes correctly.
How to Calculate Aquarium Volume (And Why It Matters for Your Fish)
Step-by-step guide to calculating fish tank volume in gallons and liters, including how to handle substrate displacement, stocking density, and medication dosing.
How Much Soil for a Raised Garden Bed: A Calculator-Backed Guide
How to calculate soil volume for a raised garden bed in cubic yards and bags, including settling allowances, soil mix recommendations, and bulk vs bagged break-even.
Swimming Pool Volume: Why Your Pool Store's Estimate Is Probably Wrong
Calculate your swimming pool's exact volume in gallons or liters, with formulas for rectangular, oval, and freeform pools, and a chlorine dosing reference table.
Will My Fridge Fit Through the Doorway? The Tilt Math Explained
How to measure a doorway and an appliance to know if a fridge, sofa, or washer will fit through. Includes the tilt-diagonal formula and tips for tight clearances.
How to Estimate Cubic Feet for a Move (Without Hiring a Mover)
Calculate the total cubic feet of your move to size a truck correctly. Includes room-by-room estimates, furniture sizes, and U-Haul/Penske truck capacities.
The Volume of a Rectangular Prism: A Complete Guide
Comprehensive explanation of how to calculate the volume of a rectangular prism, including the formula derivation, worked examples, and common student mistakes.
Cubic Centimeters vs Milliliters: Are They the Same Thing?
Cubic centimeters (cm³) and milliliters (mL) are exactly equal — here's the historical reason, when each is used, and why the confusion exists.
How to Convert Cubic Feet to Gallons (And Why It's Trickier Than You Think)
Convert cubic feet to gallons with the 7.48 conversion factor, plus US vs UK gallon differences, common errors, and a full reference table.
Surface Area vs Volume: The Difference That Confuses Everyone
Surface area and volume measure different things in different units. Here's the precise difference, with worked examples and practical applications.
The Box Diagonal Formula: Pythagoras in 3D
Calculate the space diagonal of a rectangular box using the 3D Pythagorean theorem. With derivation, worked examples, and practical applications for fitting things into boxes.
Amazon FBA Dimensional Weight: The Complete 2026 Guide
Amazon FBA fees use dimensional weight to determine size tiers. Learn the exact formulas, size-tier thresholds, and packaging strategies that reduce FBA costs.
Pallet Volume Calculation for Freight: A Warehouse Operator's Guide
How to calculate pallet volume for LTL freight, dimensional weight rules, density classification, and the freight class system every operator should know.
3PL Dim Weight Negotiation: How to Get a Better Divisor
Strategies for negotiating dimensional weight divisors with 3PLs and carriers, including realistic targets, volume thresholds, and negotiation tactics that work in 2026.
Storage Unit Sizing: How to Calculate What Actually Fits
How to size a storage unit correctly — calculate cubic feet, compare standard unit sizes, and estimate what fits in a 5x10, 10x10, and 10x20 unit.