Time and Materials: Definition and Billing Terms

Time and materials is a billing method charging actual labor hours and materials cost. Learn the rate card and cap terms that keep it auditable.

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Time and Materials: Definition and Billing Terms

Time and materials is a billing method where the vendor charges for actual labor hours at an agreed rate plus the cost of materials consumed, rather than one fixed price for the whole job. It is common in maintenance, repair, and IT and professional services work, where the scope cannot be fully defined before the work starts.

Buyers choose it because it avoids paying a fixed-price premium for uncertainty, but the tradeoff is that the invoice total is unknown until the work is finished. That is exactly where contract terms have to do the work a fixed price would otherwise do: the mechanism that causes drift is a rate card negotiated at signing getting applied inconsistently at invoice time, and what fixes it is checking every invoice against that rate card before payment.

1. What counts as materials versus labor on a time and materials invoice?

Labor is the hourly charge for the person doing the work, billed at a rate tied to their role or skill level. Materials are the parts, supplies, or consumables used to complete the job, usually billed at cost plus an agreed markup percentage. A contract should state both separately, because a vendor blending them into one line removes the buyer's ability to check either rate against the agreed terms.

When labor and materials appear as a single blended line, there is no way to confirm the hourly rate matches the contracted role rate, or that the materials markup matches the agreed percentage. Separating them is what makes an invoice auditable at all.

2. Why does a time and materials contract need a rate card?

A rate card sets the hourly charge for each labor role and the markup percentage for materials before any work begins. Without it, the vendor's invoice becomes the only record of what rate applies, which removes the buyer's ability to dispute a charge. A stated rate card turns a time and materials contract from an open-ended promise into a checkable set of terms.

A rate card should name each role that might appear on an invoice, such as technician, senior technician, and project lead, each at a distinct hourly rate. It should also state whether travel time, minimum call-out charges, and after-hours premiums apply, and at what rate.

3. How does a not to exceed cap work with time and materials billing?

A not to exceed cap sets a dollar ceiling the vendor cannot bill past without returning for approval, while still billing at actual hours and materials underneath that ceiling. It gives the buyer the cost control of a fixed price and the accuracy of time and materials billing, as long as the cap is tracked against cumulative invoices rather than checked invoice by invoice.

The cap only protects the buyer if someone is tracking cumulative billing across the life of the job, not just the current invoice. A vendor can stay under the cap on every single invoice while the running total has already crossed it.

4. What should a buyer check on a time and materials invoice before paying it?

Check billed hours against a signed timesheet or work order, confirm the labor rate matches the contracted rate for that role, verify the materials markup matches the agreed percentage, and confirm any not to exceed cap has not been silently crossed. Each check is a separate comparison against the original contract terms, not the vendor's own invoice total.

These four checks map to four distinct places drift can enter: hours with no supporting record, a role billed at a higher rate than the work performed, a materials markup applied above the contracted percentage, and cumulative billing past an agreed cap.

Freight, maintenance, and professional services invoices billed this way benefit from the same line-by-line comparison against contract terms used elsewhere in indirect spend.

  1. Hours to work order: Confirm billed hours are backed by a signed timesheet or work order, not just the vendor's own log.
  2. Rate to role: Confirm the hourly rate billed matches the contracted rate for the role that actually performed the work.
  3. Markup to percentage: Confirm materials are marked up at the percentage stated in the contract, not a different figure.
  4. Cumulative total to cap: Confirm the running total across all invoices to date has not passed the not to exceed cap.

For the wider pattern this sits inside, start with the margin drift guide.

5. Frequently Asked Questions (People Also Ask)

What is a time and materials contract?

A time and materials contract bills a vendor for actual hours worked at an agreed rate plus the cost of materials used, instead of a fixed price for a defined scope. It shifts the estimating risk from the vendor to the buyer, since the final invoice depends on how long the work actually takes.

How is time and materials different from a fixed price contract?

A fixed price contract sets one number for a defined scope regardless of hours worked. Time and materials bills whatever hours and materials the work actually consumes, so the invoice total is not known until the job is done.

What should a time and materials rate card include?

It should list a labor rate by role or skill level, a materials markup percentage, and any minimum call-out or travel charge. Without those three stated separately, an invoice cannot be checked line by line against the contract.

Does time and materials always cost more than fixed price?

Not necessarily. It depends on how well the scope was defined before work started. A fixed price for poorly defined work often carries a contingency premium built into the rate; time and materials avoids that premium but removes the cost ceiling unless a cap is negotiated.

What is a not to exceed cap on a time and materials contract?

It is a maximum dollar amount the vendor may bill under the time and materials rate before returning to the buyer for approval. It caps the buyer's exposure while preserving the vendor's actual-cost billing method.

How do you audit a time and materials invoice?

Match billed hours to a timesheet or work order, check the labor rate against the rate card by role, confirm materials markup matches the contracted percentage, and verify any not to exceed cap was not silently crossed.

1. What counts as materials versus labor on a time and materials invoice?

Labor is the hourly charge for the person doing the work, billed at a rate tied to their role or skill level. Materials are the parts, supplies, or consumables used to complete the job, usually billed at cost plus an agreed markup percentage. A contract should state both separately, because a vendor blending them into one line removes the buyer's ability to check either rate against the agreed terms. When labor and materials appear as a single blended line, there is no way to confirm the hourly rate matches the contracted role rate, or that the materials markup matches the agreed percentage. Separating them is what makes an invoice auditable at all.

2. Why does a time and materials contract need a rate card?

A rate card sets the hourly charge for each labor role and the markup percentage for materials before any work begins. Without it, the vendor's invoice becomes the only record of what rate applies, which removes the buyer's ability to dispute a charge. A stated rate card turns a time and materials contract from an open-ended promise into a checkable set of terms. A rate card should name each role that might appear on an invoice, such as technician, senior technician, and project lead, each at a distinct hourly rate. It should also state whether travel time, minimum call-out charges, and after-hours premiums apply, and at what rate.

3. How does a not to exceed cap work with time and materials billing?

A not to exceed cap sets a dollar ceiling the vendor cannot bill past without returning for approval, while still billing at actual hours and materials underneath that ceiling. It gives the buyer the cost control of a fixed price and the accuracy of time and materials billing, as long as the cap is tracked against cumulative invoices rather than checked invoice by invoice. The cap only protects the buyer if someone is tracking cumulative billing across the life of the job, not just the current invoice. A vendor can stay under the cap on every single invoice while the running total has already crossed it.

4. What should a buyer check on a time and materials invoice before paying it?

Check billed hours against a signed timesheet or work order, confirm the labor rate matches the contracted rate for that role, verify the materials markup matches the agreed percentage, and confirm any not to exceed cap has not been silently crossed. Each check is a separate comparison against the original contract terms, not the vendor's own invoice total. These four checks map to four distinct places drift can enter: hours with no supporting record, a role billed at a higher rate than the work performed, a materials markup applied above the contracted percentage, and cumulative billing past an agreed cap. Freight, [maintenance, and professional services invoices](/glossary/it-and-professional-services-audit) billed this way benefit from the same line-by-line comparison against contract terms used elsewhere in indirect spend. 1. Hours to work order: Confirm billed hours are backed by a signed timesheet or work order, not just the vendor's own log. 2. Rate to role: Confirm the hourly rate billed matches the contracted rate for the role that actually performed the work. 3. Markup to percentage: Confirm materials are marked up at the percentage stated in the contract, not a different figure. 4. Cumulative total to cap: Confirm the running total across all invoices to date has not passed the [not to exceed cap](/glossary/not-to-exceed-overrun). For the wider pattern this sits inside, start with the [margin drift](/insights/margin-drift-spend-leakage-guide) guide.

Questions & Answers

What is a time and materials contract?

A time and materials contract bills a vendor for actual hours worked at an agreed rate plus the cost of materials used, instead of a fixed price for a defined scope. It shifts the estimating risk from the vendor to the buyer, since the final invoice depends on how long the work actually takes.

How is time and materials different from a fixed price contract?

A fixed price contract sets one number for a defined scope regardless of hours worked. Time and materials bills whatever hours and materials the work actually consumes, so the invoice total is not known until the job is done.

What should a time and materials rate card include?

It should list a labor rate by role or skill level, a materials markup percentage, and any minimum call-out or travel charge. Without those three stated separately, an invoice cannot be checked line by line against the contract.

Does time and materials always cost more than fixed price?

Not necessarily. It depends on how well the scope was defined before work started. A fixed price for poorly defined work often carries a contingency premium built into the rate; time and materials avoids that premium but removes the cost ceiling unless a cap is negotiated.

What is a not to exceed cap on a time and materials contract?

It is a maximum dollar amount the vendor may bill under the time and materials rate before returning to the buyer for approval. It caps the buyer's exposure while preserving the vendor's actual-cost billing method.

Margin Drift Resources