CIS Monthly Filing Checklist

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

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