Free tools built for civil.

Excavation Volume Calculator

Calculate excavation volume, loose spoil and estimated truck loads for a rectangular dig-out.

Bank/loose m³, loads, optional tonnes

Retaining Wall Calculator

High-level quantities for pricing a retaining wall — face area, excavation, drainage aggregate, plus posts, concrete or blocks by wall type.

Face m², material m³, post/block count

Spoil Calculator

Bank to loose (or loose back to bank) with your bulking factor, plus truck loads.

Bank/loose m³ and volume-only loads

Drainage

Pipe Grade & Invert Calculator

Find fall and grade from upstream and downstream inverts, or calculate the downstream invert needed for a chosen gradient.

Fall, grade %, 1:X, invert m

Trench Calculator

Measure a rectangular trench, then separate excavation, bedding, pipe-zone aggregate, backfill and loose spoil.

Excavation, bedding, backfill m³

Pipe Bedding Calculator

Bedding and surround aggregate for a pipe run — m³ and tonnes at the density you enter.

Bedding/surround m³ and tonnes

Materials

Aggregate & Tonnage Calculator

Convert dimensions or a measured area into aggregate volume and estimated tonnes using your supplier’s density.

Volume m³ and estimated tonnes

Concrete Calculator

Slabs, footings, piers and kerbs — pick the shape, get m³ and an order volume with waste. Built for headwalls, surrounds, footings and structures, not just driveways.

Net and order volume m³

Asphalt Tonnage Calculator

Area and thickness to tonnes, using the density of the actual mix you're laying.

Compacted m³ and estimated tonnes

Plant & Cartage

Excavator Charge-Out Calculator

An indicative plant rate check — ownership, finance, running costs, operator and overheads per hour, plus the charge-out rate your margin needs.

Ownership, operation and sell NZD/hr

Truck Cycle Calculator

Work out truck cycle time and how much material your fleet can actually shift in a day.

Cycle minutes and volume m³/day

Truck Load Calculator

How many loads to cart it away — checked by bin volume AND payload, because heavy material fills the scales before the bin.

Loads by bin volume and payload

Commercial

Markup & Margin Calculator

20% markup is not 20% margin. Choose the inputs you know and see selling price, gross profit and both percentages.

Sell, profit NZD and margin %

Labour Charge-Out Calculator

An indicative check on what an hour of labour needs to be charged at once on-costs, overheads and non-productive time are covered.

Break-even and charge-out NZD/hr

Retention Calculator

Retention withheld this claim, your net claim, and the running total held — with cap handling.

Withheld, net claim and held NZD

Job Margin Calculator

Contract value less all costs — gross profit, true margin % and the markup it equates to.

Total cost, profit NZD and margin %

Crew Productivity Calculator

Turn a measured quantity and your crew's output rate into productive crew-hours, working days and paid person-hours. Use the same quantity unit throughout: metres, m², m³ or items.

Crew days and paid person-hours

Free templates

ITP Template

Inspection & Test Plan — activities, criteria, hold points, sign-off.

Template

Variation Template

Price a variation with markup and GST, print-ready.

Template

Progress Claim Template

Claim value from work to date, previous claims and retention.

Template

Pre-Start Template

Daily pre-start — crew, plant, hazards, controls, sign-off.

Template

Site Diary Template

Daily record — weather, crew, work done, deliveries, delays.

Template

Toolbox Talk Template

Topic, discussion points, hazards and attendee sign-on.

Template

Plant Inspection Template

Pre-operation plant checks, defects and safe/unsafe status.

Template

How-to guides

How to Calculate Excavation Volume

How to calculate excavation volume for civil work — bank vs loose measure, bulking factors, truck loads and a worked example. With a free calculator.

Guide

How to Calculate Pipe Fall & Grade

How to calculate pipe fall, grade percentage and 1:X gradient from invert levels — with reverse calculations and a worked drainage example. Free calculator included.

Guide

How to Price Earthworks

How to price an earthworks job — quantities, bulking, plant and truck productivity, disposal, overheads and margin, with a simple pricing framework and worked logic.

Guide

How to Calculate an Excavator Hourly Rate

How to build an excavator hourly charge-out rate — depreciation, finance, insurance, fuel, servicing, operator, overheads and margin, with a full worked example.

Guide

How to Prepare a Construction Variation

How to prepare and price a construction variation — instruction, scope, cost build-up by category, markup, records and approval, with a worked pricing example.

Guide

How to Calculate Pipe Bedding and Surround

Calculate pipe bedding and surround volumes, subtract pipe displacement and convert to tonnes. A worked example for drainlayers and civil contractors.

Guide

How to Calculate Aggregate Tonnes for a Job

Work out aggregate volume and tonnes from area, depth and material density, with a worked example and ordering checklist for NZ civil jobs.

Guide

How to Plan Spoil Removal and Truck Loads

Plan spoil cartage using bank and loose volumes, payload, truck capacity and cycle time. Includes a worked example and a practical site checklist.

Guide

How to Estimate Crew Productivity and Duration

Estimate crew days and labour hours from quantities, observed output and productive hours. A worked example for drainlayers and small construction teams.

Guide