Contracts

What is open book pricing in construction?

Open book pricing is an arrangement where the contractor shows the owner its real costs, subcontractor quotes, and markups, instead of handing over a single lump-sum number.

Two construction professionals review paper plans beside a tablet at a jobsite workbench.
Plan reviews connect field conditions, drawings, and the next decisions on a job. AI-generated illustration.

Open book pricing means the owner gets to see how the price was built. Labor, material, subcontract quotes, equipment, general conditions, and the contractor's fee are all broken out and backed by documents. It is the normal way to price a cost-plus contract or a guaranteed maximum price job, and some owners also ask for it on change orders under fixed-price contracts.

The opposite is closed book. On a lump sum contract the owner sees one number and the contractor keeps what it saves, or eats what it overruns.

How open book pricing works on a real job

Say a GC is negotiating a $1.9 million restaurant build-out with a repeat client on a GMP basis. The GC runs a competitive bid for each trade and shares the bid tabulation. The owner sees three electrical bids, the one the GC picked, and why.

Example open book GMP summary (illustrative numbers)
LineAmountBackup shared with owner
Subcontracts$1,420,000Bid tabs and signed subcontracts
Self-performed labor and material$140,000Labor rates, hours estimate, supplier quotes
General conditions$150,000Staffing plan and monthly costs
Contingency$60,000Use rules written into contract
Fee$130,000Fixed fee or percentage, per contract

During construction, each pay application carries invoices, timesheets, and sub pay apps as backup. At the end, the owner or its accountant may audit the job cost records, and any savings under the GMP split according to the contract.

Notice what the owner does not see: the GC's own overhead allocation inside the fee. Most open book deals agree on a fee percentage or fixed amount up front precisely so the contractor does not have to justify its office rent line by line. The negotiation moves from the total price to the definitions: what is cost, what is fee, and what happens to unused contingency.

Why owners and contractors use it

  • Trust on negotiated work: the owner can check the price without a hard bid.
  • Early start: pricing can be refined as the design develops, which suits design-build and CM at risk.
  • Fewer change order fights: both sides use the same cost data and agreed markups.
  • Risk is visible: contingency and allowances are separate lines, not hidden in the number.

Common mistakes and disputes

  1. Fuzzy definitions of cost. The contract must say what counts as reimbursable (for example, whether office staff time or small tools are cost or fee). See reimbursable expenses.
  2. Labor rates with hidden markup. If burden and overhead are rolled into an hourly rate, owners will ask for the breakdown.
  3. Messy job cost records. An audit with missing receipts turns into disallowed costs.
  4. Rebates and discounts. Many open book contracts require supplier rebates and early-pay discounts to go back to the owner. Know before you keep them.
  5. Treating open book as permission to overrun. On a GMP, the cap still binds.

Related terms

See also cost-plus fixed fee, markup, job costing, and the guide on cost-plus vs fixed-price contracts. Smart Business Automator keeps committed costs, invoices, and backup together by cost code, which makes open book reporting less painful.

Frequently asked questions

Is open book pricing the same as cost-plus?

Not exactly. Cost-plus is a payment method; open book is the practice of sharing actual costs. Cost-plus and GMP contracts are almost always open book, but a fixed-price job can also use open book pricing for change orders.

Does the owner get to audit the contractor?

Usually, if the contract includes an audit clause. Most open book contracts give the owner the right to review job cost records for a period after final payment.

Do subcontractors have to open their books too?

Only if their subcontract says so. On many GMP jobs, lump-sum subcontracts are shared as a single number, while time-and-materials subs must show their costs.

Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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