What Is a Labor Hour Contract? LH vs T&M vs FFP Explained

If you've spent any time reading federal solicitations, you've seen contract types thrown around like everyone is supposed to know what they mean. The most confusing pair is Labor Hour (LH) and Time-and-Materials (T&M) — they look almost identical on paper, the FAR puts them in the same subpart, and even experienced BD professionals occasionally use the terms interchangeably. They're not the same.

This guide breaks down what a labor hour contract actually is, how it differs from T&M and Firm-Fixed-Price (FFP), when the government uses each, and what each type means for your pricing strategy and risk exposure.

The short answer

A Labor Hour (LH) contract pays the contractor a fixed hourly rate for each labor category, multiplied by the actual hours worked, with no separate reimbursement for materials. It's defined under FAR 16.602 as essentially a T&M contract without the materials piece.

A Time-and-Materials (T&M) contract is the same fixed hourly rate structure, but it also reimburses the contractor for materials at cost (no profit on materials, per FAR 16.601).

A Firm-Fixed-Price (FFP) contract pays a single, agreed-upon price for a defined scope of work — regardless of how many hours it actually takes.

Side-by-side: LH vs T&M vs FFP

How a labor hour contract actually works

Picture a typical LH task order: the government needs a Senior Systems Engineer for an estimated 1,920 hours over 12 months. The solicitation requires you to propose an hourly rate for the "Senior Systems Engineer" labor category. You bid $145/hour fully burdened. Your proposed total is $145 × 1,920 = $278,400. The contract awards with a Not-To-Exceed (NTE) ceiling of $278,400.

Each month, you submit invoices for actual hours worked at $145/hour. If your engineer works 165 hours in March, you bill $23,925. If they only work 140 hours in April (vacation, holidays), you bill $20,300. You can't exceed 1,920 hours total without a contract modification — but if you hit the ceiling early, performance stops.

The key things to understand:

• The rate is fixed; the hours are not. You are guaranteed to be paid your bid rate for every approved hour. The government is not guaranteed to use all the estimated hours.
• You absorb productivity risk. If your engineer is slow and takes 200 hours to do work a more efficient engineer would do in 150, the government still only pays for the hours up to the ceiling — and the work may not get finished.
• Labor mix matters. Most LH solicitations have multiple labor categories (Junior Engineer, Senior Engineer, PM, Subject Matter Expert) each with their own rate and estimated hours. Get the mix wrong on your proposal and you either underbid the work or overprice yourself out of competition.

When does the government use LH instead of T&M?

Per FAR 16.602, the government uses Labor Hour when the work is "purely labor" — services with no significant materials, supplies, or other direct costs. Common examples include:

• Program management support
• Engineering and technical analysis
• Acquisition and contract administration support
• Cybersecurity assessments and audits
• Training and curriculum development
• Records administration and documentation

If the work also requires the contractor to procure materials — say, replacement hardware for an IT modernization, or test equipment for a system installation — the government will typically use T&M instead so those material costs can be reimbursed. Many task orders blend both: an LH portion for the core engineering services and a separate cost-reimbursable Other Direct Costs (ODC) CLIN for incidental materials and travel.

Why LH and T&M are the government's "least preferred" contract types

FAR 16.601(c) is unusually direct: T&M (and by extension LH) "may be used only when it is not possible at the time of placing the contract to estimate accurately the extent or duration of the work or to anticipate costs with any reasonable degree of confidence." In other words, the government uses these types when it doesn't know enough to write a real fixed-price scope.

From the government's perspective, LH and T&M are risky because the contractor has no built-in incentive to be efficient — you're paid for hours regardless of progress. Federal agencies are required to actively monitor performance and confirm that the work is being delivered for the hours billed. That's why LH solicitations almost always include detailed surveillance plans, monthly progress reporting, and a clearly defined Quality Assurance Surveillance Plan (QASP).

Pricing strategy on a labor hour contract

The temptation on LH is to price competitively at the low end of the market. That works if you win — but it produces three problems:

1. Margin compression at scale. A $5/hour rate cut on a 100,000-hour contract is $500,000 in foregone revenue over the life of the contract.
2. Recruiting friction. If your bid rate doesn't support a competitive salary plus your indirect rates plus your fee, you can't actually hire the personnel you proposed. We've seen contractors win awards they then can't staff because their hourly rate undershot the market.
3. Cleared talent rate floors. If the labor category requires a Top Secret/SCI clearance, your effective floor for the rate is significantly higher than uncleared work — typically a 30-50% premium for fully cleared engineering talent.

The smart approach is to build your rates from the bottom up: start with the salary your market requires, layer your fringe, overhead, G&A, and fee, and arrive at a defensible bid rate. If the resulting rate isn't competitive, that's a signal to look harder at the opportunity — not to discount your way into a contract you can't deliver.

The pricing trap: when "competitive" rates are actually predatory

On heavily competed LH/T&M task orders — especially on vehicles like SeaPort-NxG, OASIS+, Alliant 3, and GSA MAS — we routinely see bid rates 25-40% below the GSA published ceiling. Sometimes those are real efficiency plays. Sometimes they're loss-leader pricing intended to buy market share. Most of the time, they're math errors that the bidder will discover at performance start and try to recover from with task scope creep, overtime billing, or quiet labor category substitutions.

If you're competing against rates that don't pencil out, your bid/no-bid analysis should treat that as a signal — either a competitor is making a strategic loss-leader bet, or they don't understand their own cost structure. Either way, "matching them on price" is almost never the right answer.

Key personnel and labor categories

Most LH solicitations require you to propose specific named individuals for designated key personnel positions, plus rates for the broader labor category structure. The labor categories in your proposal must align with the categories in the solicitation's Performance Work Statement (PWS) and pricing schedule. Mismatches — proposing a "Sr. Cloud Engineer" when the solicitation calls for "Cloud Architect III" — get flagged as non-compliance during evaluation.

For high-volume LH bids with multiple key personnel positions, the hardest part isn't the pricing — it's identifying, qualifying, and committing the right people in the time you have between solicitation drop and proposal due date. Our Recruiter Accelerator auto-generates job descriptions, salary ranges, and boolean search strings for every key personnel position pulled directly from your solicitation, so your recruiting team can move on Day 1 instead of Day 7.

Compliance traps in LH contracts

A few things that catch contractors off guard:

• The non-commercial T&M/LH clause (FAR 52.232-7) requires that all hours billed be performed by employees meeting the solicitation's qualifications. Substituting a junior employee at the senior rate is a serious compliance issue.
• Subcontractor labor on LH/T&M contracts is governed by FAR 52.244-2 and may require advance consent from the contracting officer. Don't assume you can swap subcontractor labor under the prime's labor categories without notification.
• Timekeeping must be DCAA-compliant. Daily time entry, employee certification, supervisor approval, and audit trail. The government can (and does) audit timekeeping retroactively.
• The NTE ceiling is real. If you bill up to the ceiling and the work isn't done, you have to either negotiate a contract modification or stop work. Surprises here destroy customer relationships.

Reading LH requirements in a solicitation

When you're triaging an LH solicitation, the data points that determine whether to pursue are:

• Total estimated hours per labor category
• Period of performance (base + options)
• Place of performance (and clearance requirements that gate your talent pool)
• Key personnel positions and their experience requirements
• The pricing schedule format (does the government provide labor category definitions, or do you propose your own?)
• Any rate ceiling or "not to exceed" guidance
• Whether subcontracting is permitted and any prime/sub mix requirements

Pulling these out of a 200-page solicitation manually takes a senior analyst 2-4 hours. RFP Snapshot extracts all of them in three minutes — every key personnel requirement, every labor category, every clearance gate — into a 3-page summary your team can scan in five.

Bottom line

Labor Hour contracts are the workhorses of federal services contracting. They're flexible, they handle scope uncertainty, and they let the government scale labor up or down based on actual need. The risk is on the government side — which is exactly why LH solicitations come with extensive surveillance, key personnel commitments, and rate justifications.

For contractors, success on LH means three things: bid rates that actually support the talent you're committing to, labor category alignment with the PWS, and disciplined timekeeping and reporting from day one of performance. Get those three right and LH is one of the most stable revenue streams in federal contracting.

For the next layer of strategy on these decisions, see our guides on how to evaluate an RFP in under 10 minutes, building a bid/no-bid framework, and the hidden cost of manual RFP triage.