Is an electronic signature valid?

Yes. Under the federal ESIGN Act (15 U.S.C. ch. 96, 2000) and UETA where adopted, electronic signatures are legally binding if intent, consent, attribution, and record retention requirements are met. Exceptions apply for certain testamentary or court documents.

When is notarization required on invoices?

Invoices rarely require notarization. A notary is only necessary if the contract explicitly requires it or if local rules make a notarized document evidentiary in specific proceedings; otherwise notarization is not standard for invoices.

What if supporting receipts are missing?

Document attempts to obtain missing receipts, include vendor statements or signed affidavits when originals are unavailable, and note the reason on the invoice. Persistent gaps increase audit and payment risk, so maintain correspondence proving due diligence.

Do I need a W-9 for contractors?

Yes. Collect a completed W-9 from independent contractors before payment to capture the taxpayer identification number. Missing or incorrect TINs can trigger 24% backup withholding and IRS information-reporting penalties under IRC §6721.

Can invoices be e-signed across state lines?

Yes. ESIGN governs interstate transactions and preempts inconsistent state law where applicable; UETA governs intrastate transactions in most states. Ensure the chosen authentication method meets contractual and industry requirements and watch for state-specific exceptions.

How long should invoices be retained?

Retain invoices at least three years for tax purposes (IRC §6501), retain contract and claim records commonly for seven years, and keep HIPAA-covered records for six years (45 CFR §164.530(j)). State rules may require longer retention.

Cost Plus Invoice

This template is fully customizable. Edit the text, fill out the fields, and send it for signature. Give it a try!

COST PLUS INVOICE

From

Company Name Address

Phone

Email

Bill To

Client Name Client Address

Invoice No.:

Invoice Date:

Due Date:

Project / Job Reference:

Purchase Order No.:

Cost Basis & Markup

This invoice is prepared on a cost-plus basis. The Contractor will invoice actual direct costs and third-party charges plus an agreed markup. Enter the agreed markup to apply to direct costs:

Markup Rate Basis for Cost (describe cost categories to be billed)

Itemized Charges

List actual costs incurred. Markup may be applied per-line or applied to the subtotal per agreement.

Description	Qty	Unit Cost	Markup %	Amount

Subtotal

Markup Total

Tax

Shipping / Other

Total Due

Payment Instructions

Payment is due in accordance with the Due Date above. Accepted methods: check, wire transfer, or ACH. If remitting by check, reference the invoice number. Late payments accrue interest at the rate specified below unless otherwise agreed in writing.

Preferred Payment Details (bank or remittance instructions) Late Payment Terms

Terms, Representations & Audit Rights

The undersigned certifies that the charges billed are true, proper and allowable under the parties' agreement. All direct costs and third-party charges are billed at actual cost unless otherwise stated. The Contractor will maintain adequate records supporting billed costs and will provide access to such records for audit by Client upon reasonable notice within twelve (12) months from the date of this invoice. Unwarranted or unsupported charges discovered by audit will be credited or refunded to the Client.

Acceptance of this invoice does not waive Client's right to dispute any portion of the invoice. Any disputed portion must be raised in writing within fourteen (14) days of receipt; undisputed amounts remain payable when due. The Contractor retains all remedies available under law for nonpayment, including the right to suspend work and to assert liens where permitted.

Governing Law Additional Notes / Terms

Supporting Documentation

Receipts, subcontractor invoices and other supporting documents are available upon request to substantiate billed costs. The Contractor agrees to retain originals for the period required by applicable law.

Supporting documents included with this invoice Receipts Subcontractor invoices Available upon request

Certification

I certify under penalty of perjury that the charges invoiced are accurate to the best of my knowledge, were incurred in connection with the work described, and comply with the agreed contract terms. False certification may subject the certifier to contractual remedies and legal penalties.

Printed Name:

By:

Date:

What a Cost Plus Invoice is and when it’s used

The Cost Plus Invoice documents actual costs incurred on a project or sale and adds a pre-agreed markup or fee percentage to cover overhead and profit. It records line-item expenses—materials, labor, subcontractor fees, permits—and shows base costs, markups, taxes, and any retainage. Common in construction, manufacturing, professional services, and government contracting, the invoice ties reimbursement to verifiable expenses and must align with contract terms and applicable tax rules.

Why a clear Cost Plus Invoice matters

A clear Cost Plus Invoice ensures accurate reimbursement for actual expenses while providing an auditable record that aligns with contract markup terms. It reduces disputes, supports compliance with tax reporting, and helps clients verify charges against documented receipts and time records.

Who prepares and reviews Cost Plus Invoices

Typical users and stakeholders who prepare, approve, or review Cost Plus Invoices include project managers, contractors, and accounting teams.

Contractors and subcontractors tracking reimbursable material and labor costs per contract terms.
Project managers reconciling job budgets, change orders, and on-site expense receipts for approval.
Finance and accounts payable teams processing payments, tax reporting, and audit preparation.

Clear role definitions reduce processing delays and help ensure the invoice matches contract and regulatory requirements.

Core sections every professional Cost Plus Invoice should include

Essential sections of a professional Cost Plus Invoice ensure transparency, comply with contract terms, and provide audit-ready documentation for reimbursement.

Header

Include invoice number, issue date, billing period, and contract reference. List seller and buyer legal names and contact details to establish attribution and payment routing.

Line items

Detail each expense with date, vendor, quantity, unit cost, and extended cost. Attach or reference receipts, timesheets, and subcontractor invoices for verification, including purchase orders or delivery tickets.

Markup calculation

Show the agreed markup method—fixed percentage, fixed fee, or tiered schedule—apply it to base costs and show calculation lines so client and auditors can reproduce totals from base entries.

Taxes & Fees

Itemize sales tax, use tax, permit fees, retainage, or other statutory charges separately. Cite tax jurisdiction and registration numbers when required by law for remittance.

Supporting docs

Reference attached receipts, invoices, delivery tickets, and payroll exports. Use an indexed annex or digital folder so reviewers can locate supporting evidence quickly and consistently.

Signatures

Include signature blocks for payer and payee with printed name, title, date, and method of authentication (wet signature, electronic signature, or notarization) to establish intent and attribution.

Stepwise process to prepare and submit a Cost Plus Invoice

Follow these steps to prepare and submit a compliant Cost Plus Invoice for review and payment.

01

Gather records: Collect receipts, timesheets, POs, and subcontractor bills.
02

Calculate costs: Sum base costs and apply agreed markup method.
03

Prepare invoice: Enter items, attach supporting documents, and list taxes.
04

Send & follow: Transmit to payer with audit trail and confirm receipt.

How to configure an online Cost Plus Invoice workflow

Configure an online Cost Plus Invoice workflow to automate fields, collect supporting files, and enforce signer authentication and routing.

Field	Configuration
Line item mapping	Map spreadsheet columns to invoice line-item fields for consistent imports and templates.
Authentication level	Require email, SMS, or knowledge-based authentication per signer and document sensitivity.
Attachment enforcement	Require receipts and timesheets before the workflow advances to approval or payment.
Approval routing	Set sequential or parallel approver paths and escalation rules for overdue approvals.

Document routing and e‑submission workflow

Routing and submission steps for electronic Cost Plus Invoices help preserve evidence and speed approvals.

Upload document: Add invoice and attachments to the e-sign platform for distribution.
Assign signers: Set payer and approver roles and authentication level.
Request signatures: Send signing links or invites with authentication options.
Archive record: Store signed invoice and audit trail for retention.

Technical requirements for e-signing and e-submission

Digital signing and e-submission require a platform that preserves audit trails, controls access, and secures attachments.

File formats: PDF, DOCX, XLSX supported
Authentication options: Email, SMS, KBA, SSO available
Integrations: Connectors for CRM, ERP, cloud storage

eSignature vendor pricing and capability snapshot for invoices

This vendor comparison highlights starting prices and common capabilities relevant to Cost Plus Invoice workflows; signNow is shown first per table conventions.

	signNow	DocuSign	Adobe Sign	PandaDoc	HelloSign
Starting Price	$8/user/mo	$15/user/mo	$14/user/mo	$19/user/mo	$15/user/mo
Free Trial	7-day free trial	No	No	Yes, limited	Yes, limited
Bulk Send	Yes	Yes	Yes	Yes	No
Audit Trail	Yes	Yes	Yes	Yes	Yes
HIPAA Compliant	Yes	Yes	Yes	No	No

Essential data fields to include on the invoice

Invoice No.: Unique invoice identifier

Issue Date: Use MM/DD/YYYY format for date

Contract Ref.: Reference contract clause or ID

Cost Breakdown: Line-item costs with totals

Attachments: Receipts, timesheets, subcontractor invoices

Signatory: Printed name, title, date, method

Key penalties and legal risks if invoices are incorrect

Tax Penalties: Incorrect sales tax may trigger fines

Late Payment: Interest and collection costs accrue

Contract Dispute: Noncompliance can lead to litigation

Overbilling Risk: Intentional overcharge carries severe penalties

Backup Withholding: Missing TIN triggers 24% withholding

Audit Exposure: Insufficient support invites IRS or client audit

Common preparation mistakes to avoid

Failing to attach receipts or timesheets, leaving line items unsupported and increasing the likelihood of payment delays and audit inquiries.
Using vague descriptions like 'materials' or 'miscellaneous' without vendor names or dates, which prevents verification against purchase orders or delivery records.
Applying markups inconsistently across expense categories or failing to show calculation steps, creating disputes over total billed amounts.
Not specifying tax jurisdiction or registration numbers for taxable items, causing remittance errors and potential state audits.

Timing expectations, payment terms, and reporting deadlines

Define payment terms, dispute windows, and applicable tax reporting timelines to align invoicing with contract and regulatory obligations.

Payment terms:

Commonly Net 30 or Net 60; state contract dictates schedule

Dispute window:

Specify number of days to raise billing disputes (commonly 15–30 days)

Progress billing:

Invoice at defined milestones per contract or percent complete

1099-NEC reporting:

Report contractor payments; recipient and IRS due Jan 31

Record-keeping:

Retain supporting documentation to meet audit and tax deadlines

Real-world examples of cost-plus billing in practice

Examples show how organizations use detailed invoices and e-sign workflows to speed approvals and preserve audit trails.

Martin Properties

Martin Properties switched to electronic invoicing for property management projects to speed approvals and centralize expense documentation.

Significantly improved auditability for investors.
Tim Martin, Founder, reports that online processing ensured compliance and consistent supporting documentation, reducing disputes with contractors and enabling faster reconciliation between invoices and job cost reports using a centralized digital archive.

Optica Ventures

Optica Ventures adopted cost-plus billing to track startup project expenses and provide investors transparent documentation of capital deployment and fees.

Significantly improved auditability for investors.
Brian Fitzgibbons, COO, notes the system made it simple for his team and customers to review detailed expense line items, accelerating approvals and reducing follow-up questions from investors and partners.

Frequently asked questions about Cost Plus Invoices

Common questions about preparing, signing, and storing Cost Plus Invoices, including authentication, required documentation, and handling disputes.

Need help? Contact support

Is an electronic signature valid?
Yes. Under the federal ESIGN Act (15 U.S.C. ch. 96, 2000) and UETA where adopted, electronic signatures are legally binding if intent, consent, attribution, and record retention requirements are met. Exceptions apply for certain testamentary or court documents.
When is notarization required on invoices?
Invoices rarely require notarization. A notary is only necessary if the contract explicitly requires it or if local rules make a notarized document evidentiary in specific proceedings; otherwise notarization is not standard for invoices.
What if supporting receipts are missing?
Document attempts to obtain missing receipts, include vendor statements or signed affidavits when originals are unavailable, and note the reason on the invoice. Persistent gaps increase audit and payment risk, so maintain correspondence proving due diligence.
Do I need a W-9 for contractors?
Yes. Collect a completed W-9 from independent contractors before payment to capture the taxpayer identification number. Missing or incorrect TINs can trigger 24% backup withholding and IRS information-reporting penalties under IRC §6721.
Can invoices be e-signed across state lines?
Yes. ESIGN governs interstate transactions and preempts inconsistent state law where applicable; UETA governs intrastate transactions in most states. Ensure the chosen authentication method meets contractual and industry requirements and watch for state-specific exceptions.
How long should invoices be retained?
Retain invoices at least three years for tax purposes (IRC §6501), retain contract and claim records commonly for seven years, and keep HIPAA-covered records for six years (45 CFR §164.530(j)). State rules may require longer retention.

be ready to get more

Join over 28 million airSlate SignNow users

Sign Now