The numbers, explained.

Geometry first, purchase quantities second.

Dimensions are normalised before calculation. Theoretical area, volume or length is calculated first. Your waste allowance is applied once, followed by rounding up to whole purchased packs or pieces where appropriate. Monetary line totals are rounded to cents.

Your product specification matters.

Metandum does not assume a universal concrete bag yield, paint coverage, density, roll coverage or fixing pattern. Enter the values for the product and application you have selected. A product’s nominal size may differ from its actual or useful coverage size.

Quantity is not design approval.

These tools estimate materials from dimensions and specifications you provide. They do not choose structural sections, allowable spans, reinforcement, safe spacing, protection devices or minimum code requirements. A result is not a statement that a design is safe or compliant.

Room and run assumptions.

Rooms are rectangular. Flooring projects pool packs of the same product across rooms. Fence runs exclude gate openings; shared posts and additional gate posts are explicit inputs. Deck boards use a straight layout with whole purchased lengths per row; offcuts are not optimised.

Cutting and roll assumptions.

Wallpaper uses full-height drops and supplied repeat settings; rolls for different cut heights stay separate. Carpet uses strip counts for each room. The stock cut list uses first-fit decreasing and the sheet cut tool compares uniform grids; neither guarantees optimal nesting.

New landscape and tile projects.

New soil fill, existing mulch and separate sand layers stay distinct. Tile counts follow a grid with your supplied joint width; grout uses your supplied joint depth and prepared-material density. The tools do not select a substrate, waterproofing system or construction thickness.

Sources and verification.

Basic geometry follows dimensional arithmetic. Material-dependent inputs come from your selected product or plan. Formula checks cover reference quantities, unit conversions, rounding, invalid inputs and project combinations. No professional engineering approval is claimed.

Use the current published technical data for your selected product when entering its yield, coverage or package size. Product source data are references for supplied inputs, not product recommendations.

Saved locally, under your control.

New material projects use free browser storage (IndexedDB); calculator drafts and original templates also remain on this device. Existing cloud guest/account projects retain their access and can be copied into browser storage. Clearing browser data may remove local projects and history, so keep a JSON backup. Cloud accounts are planned at USD $9/month; the launch waitlist stores only your email and consent in our database. No payment or analytics provider is connected.

What costs include.

Project totals cover priced material rows only. Unpriced rows remain visible and do not silently become zero-cost items. Delivery, equipment, labor and taxes are excluded from the material subtotal. Optional project allowances accept these amounts and markup explicitly, without selecting rates or tax rules.

Calculation documentation updated 4 October 2026 · Formula version 1.0