Checklist
CIS Monthly Return Checklist (CIS300)
CIS Monthly Return Checklist (CIS300) gives UK accountancy teams a practical workflow for repeat client work. Preview the key steps below, download the full checklist, then turn it into a recurring Remindoo workflow with owners, reminders and visibility.
Turn this into a recurring workflow in Remindoo
Create a service template, add subtasks, set trigger dates and assign owners so this checklist runs automatically for every relevant client.
Missing the CIS300 deadline is one of the most common reasons contractors receive unexpected penalties, particularly for first-time CIS contractors. Remindoo is a CRM built specifically for accountants and treats CIS as a specialised service. It offers a specialised CIS workflow that covers handling subcontractor verifications and also the monthly returns.
So, when you use Remindoo, you should ensure every deduction is accurate, and every deadline is met confidentially.
Verifying the Subcontractor
First, you should register with HMRC for CIS through their official website or by directly contacting them online. After that, you should verify the tax status of a subcontractor with HMRC before any transaction takes place. This helps to ensure your contractor client is not held liable for under-deducted tax later on.
Payment Calculation & Labour Split
You must apply CIS tax to the labour portion of an invoice only. Check the subcontractor’s breakdown to avoid deducting tax from materials or VAT.
Payment & CIS Deduction Statements
Contractors must provide subcontractors with a statement explaining all deductions within 14 days of the tax month’s end. Yes, these statements are necessary for subcontractors to file their Self-Assessment or Corporation Tax returns.
Submit Monthly CIS Return (CIS300)
The CIS300 is a strict and mandatory monthly report for HMRC. It is filed on the 19th of each month following the tax month cycle. If missed, then automatic penalties will be triggered.
Report Gross Payment Status
This step is often missed when contractors assume gross status applies automatically and it can lead to reporting errors. Therefore, subcontractors should apply for gross payment status to receive full payments without any deductions (where applicable). This can help their cash flow, but contractors are required to verify these payments and report them to HMRC.
CIS Tax Payments To HMRC
Contractors must pay the CIS deductions that are held back from subcontractors to HMRC. Usually, this is paid in addition to the contractor’s monthly PAYE liabilities. Of course, paying on time is important to prevent penalties from HM Revenue and Customs.
Why use Remindoo CRM for CIS?
Managing CIS compliance can be challenging, with tasks like calculating deductions, submitting monthly returns to HMRC, and ensuring accurate payments to contractors. Manual tracking or relying on spreadsheets increases the risk of errors, missed submissions, and potential penalties. Remindoo CRM automates the entire CIS process, centralises tasks, and provides reminders at every stage, ensuring accuracy, efficiency, and compliance while freeing your team to focus on core accounting work.
How It Works
- Create CIS as a separate service and set the frequency to monthly
- Create tasks, subtasks, and CIS-specific checklists
- Set up automated reminders and send notifications to clients
- Assign associated services for each client as needed
- Assign team members to each service to ensure clear ownership and accountability
- Schedule work around client CIS deadlines to ensure timely completion
- Send reminders to internal teams as deadlines approach
- Monitor progress in a single central system, eliminating the need for Excel trackers
In short: Remindoo standardises CIS management, automates recurring tasks, and reduces errors. Teams can process CIS submissions efficiently, stay compliant, and focus on reporting and strategic insights while the system handles reminders, tracking, and workflow in one central platform
Ready to Transform Your Practice?
Join hundreds of accounting firms already using Remindoo to streamline their operations and grow their business.
Why recording every task matters in an accountancy practice
Accounting firms run on deadlines: VAT returns, payroll, confirmation statements, accounts and Self Assessment. Recording every job as a task, with an owner and a date, is the simplest way to make sure nothing is missed.
Avoid penalties
HMRC and Companies House charge penalties for late filing. A task for every deadline, with an internal date before it, gives the team a buffer.
Nothing depends on memory
Recorded tasks mean work continues when someone is off sick, on leave or has left the firm.
Consistent quality
Subtask checklists make every job follow the same steps and reviews, whoever does the work.
Visibility for managers
Filters by owner, status and deadline show at a glance what is late, what is due and who needs help.
Practical tips from UK practice
- Set an internal deadline two to four weeks before every statutory deadline.
- Use recurring tasks for repeat work such as VAT, payroll and bookkeeping.
- Break larger jobs into subtasks, including a review step.
- Comment on the task instead of by email, so the history stays with the work.
Related Remindoo features
Written and reviewed by Annie, Product Lead at Remindoo. Guidance is general; check current GOV.UK and professional body guidance for your firm.
What UK practices say about Remindoo
Read all reviews on Trustpilot“With Remindoo, everything from the first enquiry to onboarding and ongoing client management is tracked in one place… It saves us hours and gives me, as a practice owner, complete visibility of where the firm stands.”
“The biggest benefit is having clients, tasks, deadlines, workflows, proposals and communication all organised in one place.”
“During my trial, the team were absolutely amazing. They helped onboard my clients, set up my settings and made sure everything was ready for me to use… they made the whole process completely stress-free.”
“It brings client information, tasks, recurring deadlines, workflows and reminders together in one place, giving us much better visibility across the team.”
