The quantity on the plans and the quantity you have to move are two different numbers. Bidding dirt work well is mostly about knowing where those two numbers separate and who pays for the difference.
Start with the balance, not the price
The first question on a dirt job is not what a yard costs. It is whether the site balances. Total the cut, total the fill, and see what is left over. A site that balances is a job where you move material once. A site that is short on fill means imported borrow, trucking, and a material cost you have to source before you can price it. A site with excess means export, and export means haul distance, a place to put it, and possibly a tipping fee.
That single number drives most of the bid. Two contractors can have identical production rates and be a hundred thousand dollars apart because one of them found the site was forty thousand yards heavy and the other assumed it balanced.
Check the plans for a stated earthwork summary before you compute your own, then compute your own anyway and see whether you agree. Where you disagree by a lot, that is either a mistake on your side or a question worth asking before bid day.
Cut and fill: grid method and cross section method
The grid method overlays a grid on the site, takes existing and proposed elevations at each grid point, and computes the depth of cut or fill at each node. Multiply average depth by grid cell area and total it. It suits open sites, building pads, and parking lots where the surface changes in two directions. Tighten the grid where the ground rolls; a grid too coarse across a swale will quietly lose volume.
The cross section method takes sections at regular stations along an alignment, computes the cut and fill area at each section, and applies the average end area between consecutive sections to get volume. It suits roadway, channel, and pipeline work, where everything is organized along a centerline anyway. Where grade changes sharply between two sections, add a section rather than letting the average end area smooth over it.
Either way, be explicit about what is included in the earthwork number and what is not. Topsoil strip and respread, unsuitable material undercut, muck excavation, and rock are frequently separate pay items or separate exclusions, and they are a common source of a bid that looks low for the wrong reason.
Bank, loose, and compacted yards are three different numbers
Material occupies different volumes in three states. In place and undisturbed it is measured in bank cubic yards. Dug up and in the truck it is loose cubic yards. Placed and compacted in a fill it is compacted cubic yards. The same dirt is all three at different points in the day.
This matters because different parts of the bid are priced against different states. Excavation quantities usually come off the plans in bank yards. Hauling is constrained by truck capacity, which is a loose volume and often a weight limit before it is a volume limit. Fill placement is specified as compacted volume against a density requirement. Pricing all three off one number is how a job gets short on trucking.
Swell is the expansion from bank to loose. Shrink is the reduction from bank to compacted, and for most soils it takes more than a yard of cut to make a yard of compacted fill. The commonly cited ranges vary widely by material, and blasted rock behaves differently again because it swells hard and does not shrink back. Use the geotechnical report for the job as the governing source rather than a generic table, and where the geotech is silent, say in your bid what factor you assumed.
Trench work: the quantities the plans do not give you
Utility plans give you pipe length, size, and inverts. They do not usually hand you the excavation volume, and that is the number that costs money. Trench volume is a function of width and depth, and trench width is driven by the pipe outside diameter plus working clearance, or by the trench detail in the specifications, not by the pipe size alone.
Depth comes from the inverts, and it is rarely constant. A run at three feet of cover at the upstream end and eleven at the downstream end is not an average-depth job you can price with one number, because sheeting, shoring, dewatering and production rate all change as you get deeper. Break the run into reaches by depth band.
Then account for what fills the trench back in. Bedding under and around the pipe, and backfill above it, are usually different materials with different specifications, and the pipe itself displaces volume. Where the specification calls for imported select backfill instead of native, that is purchased material and a second haul. Where it allows native, you still need somewhere to put the spoil you are not putting back.
Do not forget the things that are not pipe: manholes and structures, connections to existing, pavement cut and restoration, traffic control, testing, and dewatering. On urban utility work those items regularly outweigh the linear footage.
Plans quantity versus measured quantity
On public work, some pay items are paid on the quantity shown in the plans rather than what gets field measured. Agencies label these explicitly. TxDOT's construction contract administration guidance, for example, states that measurement of actual quantities is not required where a pay item states under Measurement that it is a plans quantity measurement item, and that monthly estimates for those items can be established from the plan quantities or an agreed payment formula such as a percentage of the total plan quantity installed.
The practical consequence is that on a plans quantity item, the plan number is the number, and finding out later that you moved more dirt than the plans showed does not by itself change what you are paid. That risk has to be priced at bid time, not discovered at the end.
It also means the plans are worth checking hard before bid. If you believe a plan quantity is wrong on an item that will be paid as plans quantity, that is a question for the bidding period, and a written answer during bidding is worth considerably more than an argument during construction.
Where IAOIntel fits
IAOIntel connects takeoff quantities to what actually gets installed, so the assumptions behind a bid stay attached to the job instead of living in one estimator's spreadsheet. When the field reports installed footage and depth by station, the comparison against the bid quantity is available while there is still time to act on it.
That same record is what makes the next bid better. A company that can see where its earthwork and trench quantities ran over is bidding from its own history rather than from a rate somebody wrote down years ago.