Concrete tube calculator

The engine models a right circular cylinder: radius is half the diameter after converting inches to feet, volume in cubic feet is pi times radius squared times height, cubic yards divide that volume by twenty-seven, and bags ceiling-divide cubic feet by the yield of one eighty-pound bag unless you override bag_volume. Zero or negative diameter or height is rejected with invalid_input. Successful API calls are billed at $0.002; failed validation is not charged.

How tube-form volume and bag count are computed

Approximate bag count divides cubic feet by bag_volume, the cubic-foot yield of one sack, then ceilings to a whole number because stores sell whole bags. When bag_volume is omitted the calculator uses zero point six cubic feet, the published yield of a typical eighty-pound bag, and sets bag_volume_defaulted to true so API clients can see that the bag size was assumed. The pipeline is deterministic floating-point arithmetic with no random seeds, no wall-clock timestamps, and no network calls, so identical inputs always produce identical JSON. Diameter and height must both be strictly positive: zero or negative dimensions are rejected with invalid_input because a non-positive tube cannot hold concrete. bag_volume, when provided, must also be strictly positive so the ratio is defined.

What you send and what you get back

Send two required finite numbers: diameter for the inside diameter of the tube form in inches, and height for the pour height in feet. Optionally send bag_volume as the cubic-foot yield of one bag; if you omit it the default zero point six applies. Aliases d, dia, and tube_diameter map to diameter; aliases h, length, depth, and tube_height map to height. Missing required fields, non-numeric strings, NaN, and Infinity fail with invalid_input and are not charged. When diameter or height is zero or negative the request fails with a message that the dimension must be positive, so a form can highlight the field instead of returning a zero or negative volume. On success the response echoes cleaned inputs, radius_feet, volume_cubic_feet, volume_cubic_yards, the bag_volume used and whether it was defaulted, bags_exact, integer bags, spare_volume, a unit_note that diameter is inches and height is feet, and a short formula string for documentation. A twelve-inch by four-foot tube with the default bag yield is a classic check: cubic feet is pi, cubic yards is pi over twenty-seven, bags_exact is pi over zero point six, and bags ceilings to six. Another useful check is an eight-inch by three-foot form with bag_volume zero point four five for sixty-pound sacks: the same cylinder identity, a different purchase count. Pricing for successful API calls is the published base of $0.002 per item; validation failures do not consume prepaid balance. Upper and lower limits keep intermediate products finite: each field must be at least a tiny positive number and at most a published ceiling so a Worker isolate never emits Infinity.

Where a concrete tube calculator earns its keep

Fence and deck crews pour many matching round piers from a schedule of diameters and depths; a deterministic endpoint that returns cubic yards next to bags lets the estimator compare a ready-mix ticket against a bagged DIY option without a spreadsheet drifting between the office and the field. Because this capability is a pure parse engine, API pricing is the published base of $0.002 per successful item and failed validation does not consume balance.