Switching HR and Payroll Software on 1 January: The Singapore SME Carry-Over List

You can switch HR and payroll software on 1 January, and for a Singapore SME it is the only clean date to do it. But the switch is not finished on 1 January, because the old system still has to produce last year's IR8A by 1 March. The rule is simple: go live on the new system in January, keep the old one readable until the tax filing is accepted, and prove the new configuration in a December parallel run while the old system is still the one that pays people. Skip the parallel run and the first error you find will be a CPF underpayment on real salaries.

Why is 1 January the only clean date to switch payroll software?

Three figures in Singapore payroll run on the calendar year, not on your financial year.

• CPF Additional Wage ceiling. The amount of bonus that attracts CPF depends on the ordinary wages you already paid that same year. Switch in June and the new system does not know what the old one paid, so the AW ceiling is computed off half a year of wages.
• IR8A. It is a whole-year statement per employee. A mid-year switch means stitching two part-year records together by hand, for every employee, under a 1 March deadline.
• Leave and statutory entitlements. Most SMEs run leave on the calendar year too, so 1 January is also the natural zero point for balances.

A 1 January go-live resets all three to zero and removes the stitching entirely. The one exception: if your leave year runs April to March, your leave balances are mid-cycle on 1 January and must be migrated as opening balances with their original expiry dates intact.

What must you carry over before the old system goes dark?

Exported data is not the same as working configuration. Carry over both, and give each line an owner and a tick box.

• Closing year-to-date figures per employee for the year just ended: gross, CPF employee and employer, SDL, foreign worker levy, donations. You need these outside the old system, in a spreadsheet you control.
• Employee master data that drives rates: date of birth (CPF age bands), residency status, Permanent Resident start date and the graduated or full rate election, and the self-help group fund flags.
• Which pay items attract CPF and which do not. This is the single most common silent error in a migration. Reimbursements and certain allowances are not CPF-liable; if the import marks them as wages, you overpay CPF quietly every month.
• Bank account details, re-verified. Do not trust the import file. Confirm every account against a source you already hold, because a migration is exactly the moment a changed account number passes without question.
• Leave entitlements, pro-rated balances, carry-forward caps and expiry dates.
• Approval hierarchy and visibility. Who approves leave, and who can see other people's salaries.
• IR8A setup: benefits in kind, exempt items, and anything the old system had configured over years of filings.

How long must the old system keep running?

Longer than most owners budget for. Keep it live and readable until all of the following are true:

1. The IR8A submission for the year just ended is filed and accepted. Employers with five or more employees must submit under the Auto-Inclusion Scheme, and the deadline is 1 March.
2. Any open government-paid leave or National Service make-up pay claims are settled, because those claims need payslip and wage evidence from the period they cover.
3. You have satisfied MOM record keeping: employment records for current staff and for staff who have left must be retained, and payslip records go with them.

Budget for about three months of overlapping licence fees. For a ten-person company that is a small number next to the cost of reconstructing a year of payroll from PDFs. Before you cancel anything, take a full data export and a human-readable archive: PDF payslips, CSV wage registers, the filed IR8A files. Access usually dies the day the subscription does.

What breaks on the first January payrun?

Almost always configuration, not data. The recurring list:

• CPF ceilings and senior worker contribution rates loaded from the wrong year. Confirm the Ordinary Wage ceiling and the Additional Wage ceiling in force, and the age band rates, against CPF Board figures rather than the vendor's default template.
• Allowances flagged CPF-liable when they are not, or the reverse.
• January joiners with no year-to-date record, so pro-rating runs on a full month.
• The bank payment file rejected on format. Test it with a single employee before the full run.
• Payslips missing items MOM requires on an itemised payslip.
• No authorisation yet for the new software to submit CPF, so the payrun is correct and the contribution is late.

What does a safe December parallel run look like?

Run December payroll in both systems. Pay people from the old one. Then compare, per employee and in total: gross, net, CPF employee, CPF employer, SDL, levy, donations. Investigate every difference down to the cent, and write down the cause of each before you accept it. Rounding differences are acceptable once explained; a difference you cannot explain is an unresolved configuration error.

It takes a couple of hours for a small team and it is the only test that catches these faults while the old system is still authoritative and nobody has been underpaid.

Who needs re-authorising before you can actually pay anyone?

The new software cannot inherit your permissions. Before the first live run, confirm the vendor is on IRAS's list of payroll software that supports the Auto-Inclusion Scheme, grant the new system authorisation to submit CPF through Corppass, set up and test the bank payment channel, and tell staff where their payslips now live and how they log in. Turn on two-factor authentication for every administrator account on day one, not later, because the new system holds every salary in the company.

The order of work

1. Late October: choose the vendor, confirm AIS support, agree the migration scope in writing.
2. November: load employee master data and pay item configuration; verify CPF liability flags item by item.
3. December: parallel run, reconcile to the cent, fix and re-run.
4. 1 January: go live on the new system. Do not cancel the old one.
5. January to February: file last year's IR8A from the old system, archive everything, then cancel.

Frequently asked questions

Can we switch payroll mid-year if we have to?

Yes, but you must load opening year-to-date figures for every employee into the new system, or the Additional Wage ceiling and the IR8A will both be wrong. Plan for manual reconciliation at year end and keep the old system's wage register for the part-year it covered.

Do we need to tell MOM or IRAS that we changed payroll software?

There is no notification for the change itself. What matters is that your new software is on IRAS's list of providers supporting the Auto-Inclusion Scheme, that it is authorised through Corppass to submit on your behalf, and that your payslips and employment records still meet MOM requirements.

How long do we keep the old payroll records after the switch?

Keep them until the IR8A for the final year is filed and accepted, until any government-paid leave or NS claims for that period are settled, and for as long as MOM record keeping requires for current and former employees. In practice, archive the exports permanently; storage is cheap and reconstruction is not.