How to Invoice for Hourly Work: Timesheets, Rates and Examples
A practical guide to billing by the hour: tracking time, rounding rules, writing hourly line items, attaching timesheets and avoiding disputes.
When hourly billing makes sense
Hourly billing suits work where the scope is hard to predict: consulting, support, maintenance, legal or bookkeeping work, tutoring and many trades. It protects you from unlimited scope creep, and clients pay only for time actually spent. The trade-off is that clients need to trust your time records, so the invoice must make your hours easy to understand and verify.
Step 1: Track time as you work
Record time on the day you do it, not from memory at month end. For each entry, note the date, start and end time (or duration), the task, and the project or client. A spreadsheet is enough; a time-tracking app is helpful if you work across many clients.
Good entries are specific: "Debugged checkout payment error and deployed fix: 2.5 h" is far easier to approve than "Development: 2.5 h".
Step 2: Decide your rounding rule
Agree a rounding rule in advance and apply it consistently. Common options are:
- Exact minutes (most transparent)
- Nearest 15 minutes (0.25 h), the most common professional standard
- Nearest 6 minutes (0.1 h), used by many law firms
- A minimum charge per call-out or session, e.g. 1 hour
State the rule in your contract or on the invoice. Rounding every task up to a full hour without agreement is a quick way to lose trust.
Step 3: Write the line items
You have two good options:
Option A: one line per task or week
| Description | Hours | Rate | Amount |
|---|---|---|---|
| Week of 1 Sep: API integration and testing | 12.5 | 80.00 | 1,000.00 |
| Week of 8 Sep: bug fixes, client call (1 h) | 6.0 | 80.00 | 480.00 |
| Week of 15 Sep: deployment and documentation | 8.25 | 80.00 | 660.00 |
Option B: one summary line plus an attached timesheet
"Development services, 1–30 September 2026 (see attached timesheet): 26.75 h × 80.00 = 2,140.00". This keeps the invoice short while the timesheet gives full detail.
In our invoice generator, enter hours in the quantity field and your hourly rate in the rate field; the line total calculates automatically, including decimal hours such as 8.25.
Step 4: Attach a timesheet
For anything beyond a few hours, attach a simple timesheet (PDF or spreadsheet) with date, task and duration. Many clients, agencies and staffing firms require one. The total of the timesheet must exactly match the hours on the invoice.
Different rates for different work
If you charge different rates (for example standard and urgent work, or senior and junior staff), show them as separate lines. Never blend them into one average rate; clients cannot check it, and it hides the value of your premium work.
- "Senior consultant: 10 h × 120.00"
- "Junior analyst: 16 h × 60.00"
- "Out-of-hours emergency support: 2 h × 150.00"
Expenses and travel
Bill expenses as separate lines, ideally with receipts. If you charge for travel time, say whether it is billed at your full rate, a reduced rate, or not at all, and agree this before you travel.
Caps and estimates
Clients often ask for an estimate of hours. If you give one, track progress against it and warn the client before you go over: "We're at 18 of the estimated 20 hours; finishing will take about 6 more." Surprises at invoice time cause most hourly-billing disputes. See invoice vs estimate for how estimates relate to final invoices.
How often to invoice
For ongoing hourly work, invoice weekly, every two weeks or monthly. Shorter cycles mean smaller invoices that are easier to approve, and less money at risk if a client stops paying. Choose one cycle per client and keep to it.
Checklist
- Time recorded daily with task descriptions
- Rounding rule agreed and applied consistently
- Hours × rate shown on each line
- Different rates on separate lines
- Timesheet attached and totals matching
- Billing period stated clearly
For freelancers, our freelancer invoice guide covers the rest of the invoice, and how to get paid faster helps the money arrive sooner.
Frequently asked questions
How do I convert minutes to decimal hours on an invoice?
Divide the minutes by 60 and add the result to the whole hours. For example, 15 minutes is 0.25 hours, 30 minutes is 0.5, 45 minutes is 0.75, and 1 hour 20 minutes is about 1.33 hours. Multiply the decimal hours by your rate for the line total. Round to two decimal places consistently so your timesheet and invoice always match.
Should I show my hourly rate on the invoice or just the total?
Show the hours, the rate and the total on each line. Clients approve hourly invoices more quickly when they can check the maths themselves, and many finance teams will query a lump sum with no breakdown. Showing the rate also reminds clients of what was agreed, which helps when you later need to discuss a rate increase.
What should I do if a client disputes the hours on my invoice?
Respond quickly and share the detailed time records behind the disputed lines, including dates and task descriptions. Offer a short call to walk through them. If only part of the invoice is disputed, ask the client to pay the undisputed amount now while you resolve the rest. If you made an error, correct it with a credit note rather than editing the original.
What is the difference between an hourly rate and a day rate?
An hourly rate bills each hour you work, while a day rate is a fixed charge for a working day, regardless of the exact hours. Day rates suit on-site or full-day engagements and are simpler to invoice. Define what a day means in your contract, for example 7.5 hours, and how partial days and overtime are charged.
Should I bill for meetings, emails and phone calls?
You can, as long as your contract says so. Many professionals bill all client time, including calls and meetings, while others include short emails in their rate. Decide your policy before you start and apply it consistently. On the invoice, list meetings and calls as their own entries, such as Client call: project scope review, 0.5 h, so nothing looks hidden.
How do I raise my hourly rate for an existing client?
Give written notice before the change takes effect, commonly 30 to 60 days, and say exactly when the new rate starts. Check your contract first, as it may set rules on rate changes. On the first invoice at the new rate, add a short note confirming the change so the client's finance team is not surprised by a different number.
Can I put hourly and fixed-fee items on the same invoice?
Yes. List each type on separate lines so the client can see what is billed by time and what is a fixed price. For example, show Website maintenance retainer, October as a fixed amount, then Additional development work: 6 h at your hourly rate. Keep the billing period consistent for both types so the invoice matches your contract and timesheet.
How do I invoice hourly work done by a subcontractor?
Bill the subcontractor's hours on separate lines with their rate, or with your agreed resale rate if you add a markup. Check that your contract with the client allows subcontracting and any markup. Keep the subcontractor's own invoice and timesheet on file so you can support your figures if the client asks, and make sure their hours match what you bill.
Should I charge for time spent fixing my own mistakes?
Generally, no. Most clients expect you to fix your own errors at your cost, and billing for them is a common cause of disputes. Rework caused by the client, such as changed requirements or late feedback, is different and is usually billable if your contract says so. Label that work clearly, for example Rework after scope change approved on 3 October.
How do I work out what hourly rate to charge?
Start with the income you want each year, add your business expenses, taxes and time off, then divide by the hours you can realistically bill. Billable hours are usually far fewer than hours worked, because admin, sales and learning are unpaid. Then compare the result with typical rates in your field and adjust for your experience and the value you deliver.
Invoice Creator Editorial Team
Guides on invoicing, cash flow and small-business finance from Invoice Creator, operated by Next Software Development Company. Content is reviewed for accuracy against the fields our own invoice generator produces.
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