Free Invoice Tools for Contractors
Calculate late fees, generate demand letters, build payment terms, and figure out how much slow-paying clients are costing your business. Built for trades professionals — plumbers, electricians, HVAC techs, roofers, and contractors.
Invoice Generator
Create professional invoices and download them as PDFs instantly. 6 themes, accent color customization, tax and discount support. No signup required.
Create an invoiceDSO Calculator
Calculate your Days Sales Outstanding and see how much cash late-paying clients are costing you. Get a personalized estimate of how much faster you could collect.
Calculate your DSODemand Letter Generator
Generate a professional, state-aware demand letter for unpaid invoices. Choose your tone — firm, final notice, or pre-litigation — and get a letter ready to send in 60 seconds.
Generate a demand letterLate Fee Calculator
Enter your invoice amount, days overdue, and state to calculate the maximum legal late fee you can charge. Includes a full breakdown with your state's interest rate cap.
Calculate late feesPayment Terms Generator
Generate copy-pasteable payment terms for your invoices and contracts. Choose your industry, deposit structure, milestone preferences, and state-specific late fee language.
Generate payment termsWhy we built free tools for contractors
Late payments are the biggest cash flow problem for trades businesses. The average contractor is owed $17,500 in outstanding invoices at any given time, and most spend 15–30 minutes per overdue invoice writing follow-up emails and tracking who owes what.
We built these tools because the people who need them are the exact people InvoiceFlows is designed for. If you're Googling “how much late fee can I charge in Texas” or “demand letter for unpaid invoice,” you're dealing with a problem that shouldn't exist in the first place — and that's what our paid product solves.
Every tool on this page runs entirely in your browser. We don't store your data, require an account, or gate anything behind an email wall. Use them as often as you need.
More free resources
Tired of chasing invoices manually?
InvoiceFlows sends AI-written payment reminders that escalate from friendly to firm — so you get paid without the awkward phone calls. $9/month, 30-day free trial, no credit card required.
Start Free TrialFrequently asked questions
Are these tools really free?▾
Yes — completely free, no signup or credit card required. We built these tools because contractors searching for help with late payments are the exact people InvoiceFlows is built for. If you find the tools useful, we hope you'll try our paid product too.
Who are these tools built for?▾
Primarily for US-based trades professionals — plumbers, electricians, HVAC techs, roofers, general contractors, landscapers, and similar businesses that invoice clients and deal with late payments. Freelancers and consultants will find them useful too.
Is the legal information in these tools accurate?▾
We've researched state-specific statutes for all 50 states, but laws change and your situation may have unique factors. These tools provide general information — not legal advice. For disputes involving significant amounts, consult a licensed attorney in your state.
How is InvoiceFlows different from these free tools?▾
These tools solve one-time problems (calculating a late fee, writing a demand letter). InvoiceFlows automates the entire payment recovery process: AI writes personalized reminders, tone escalates automatically over time, and clients can respond directly. It prevents the late-payment problem from happening in the first place. $9/month, 30-day free trial.
Do you save my data when I use these tools?▾
No. All calculations and document generation happen in your browser. We don't store your invoice details, client information, or generated documents on our servers.