How to Check a Car Plate Number in Singapore (and the Checksum Formula)

There are two distinct reasons people search for "check car plate number Singapore." The first is practical: you want to look up a vehicle's registration details — COE expiry, road tax status, ownership history. The second is technical curiosity: how does the Singapore plate numbering system work, and what is the checksum letter at the end? This post covers both.

How to Check a Vehicle by Plate Number via OneMotoring

The primary way to look up a Singapore vehicle by its registration number is through the LTA's OneMotoring portal.

For basic public information (no login required): 1. Go to onemotoring.lta.gov.sg 2. Select "Vehicle" from the main navigation 3. Choose "Search Vehicle Information" or "Enquire Vehicle Details" 4. Enter the full vehicle registration number (e.g., SGA1234Z) 5. The public view shows: vehicle make and model, registration date, COE expiry date, road tax expiry date

This is the quickest way to verify COE remaining on a used car you're evaluating — you can check it directly from the listing's plate number without needing the seller's assistance.

What you can and cannot check without Singpass: - You CAN check: registration date, vehicle make/model, COE expiry, road tax status - You CANNOT check: owner identity, OMV, ARF paid, PARF rebate, outstanding loans (encumbrances)

To see the full financial details — particularly the PARF value and any encumbrances — you need to either log in with Singpass (which shows your own vehicles) or request the seller to show you the full log card directly.

Alternative Lookup Methods

Via SMS: You can text a vehicle plate number to 74688. LTA will reply with the road tax expiry date and basic vehicle info. This works without an internet connection and is useful for quick checks at a car fair or viewing.

Via third-party platforms: Sgcarmart, Motorist.sg, and other platforms offer vehicle history report lookups that compile OneMotoring data alongside reported accidents and insurance claims. These typically cost S$5–15 per report and give a more complete picture than the free OneMotoring search for used car purchases.

Why Checking the Plate Number Matters When Buying Used

When evaluating a used car:

COE remaining: The most important number. Cross-reference the registration date and COE expiry against the listing claims. Sellers occasionally misstate remaining COE (intentionally or by mistake). The OneMotoring check takes 30 seconds and confirms the actual expiry date.

Registration date for PARF purposes: As covered in detail in other posts on this site, whether the car was registered before or after 13 February 2026 determines which PARF rebate schedule applies. This directly affects the car's deregistration value and should influence the price you're willing to pay. The plate lookup confirms this date definitively.

Road tax status: A car with expired road tax at time of sale has a minor complication — the buyer needs to pay road tax from the transfer date. This isn't a dealbreaker but is worth knowing before transfer.

Understanding the Singapore Car Plate Number Format

Singapore vehicle registration numbers follow a specific format: S[prefix][letters][numbers][checksum letter].

The current format (Series S) looks like: SBA1234Z or SGA5678A.

Breaking it down: - S: Indicates a private car - B/G/H/J/K etc.: The series prefix, assigned sequentially as old series fill up - Four-digit number: Sequential within each series - Final letter (checksum): Calculated from the preceding letters and numbers

Other prefixes include: - E: Electric vehicles (older designation) - GBE, GBF, etc.: Newer private car series - PA: Private hire vehicles - SL: Taxis - GX: Goods vehicles - FBA, FBB: Foreign-registered vehicles from Malaysia (with VEP)

The Singapore Plate Checksum Formula

This is the technical answer for those searching the checksum calculation specifically. The checksum letter is derived from a weighted sum of the letters and numbers in the plate, ensuring that the full registration number is self-validating.

The formula:

1. Convert the non-numeric prefix letters to numbers (A=1, B=2, C=3, ... S=19, etc.)
2. Assign weights to each position in the registration number
3. Multiply each digit/converted letter by its weight
4. Sum all the products
5. Divide the sum by 19 and take the remainder
6. Map the remainder to a checksum letter using the LTA's assigned sequence

The LTA's checksum letter sequence (remainder 0 through 18) maps to: A, Z, Y, X, U, T, S, R, P, M, L, K, J, H, G, E, D, C, B.

Why 19 remainders? The sequence uses 19 letters (not all 26) — it skips I, O, N, V, W, F, and Q (some for visual clarity, some for technical reasons).

Practical use of the checksum: If you see a plate number that doesn't pass the checksum formula, it may be a fake, misrecorded, or the plate has been tampered with. Car dealers and LTA officers can immediately verify a plate's validity using this formula. For ordinary buyers, it's useful for spotting plates that have been cloned (copied from a legitimate vehicle onto a different one) — a legitimate-looking plate that fails the checksum is a significant red flag.

What the Plate Number Cannot Tell You

The registration number alone reveals: - Vehicle type (car, taxi, goods vehicle) - Approximate registration era (from the series prefix) - Whether the vehicle is legitimately registered

It does NOT reveal: - Actual accident history - Mechanical condition - Whether it's been modified or exported - Outstanding finance (encumbrance) - The seller's identity

For used car purchases, the plate number check is a starting point, not a complete due diligence process. The full log card view (via seller's OneMotoring or a vehicle history report) gives you the financial data that actually drives the purchase decision.

For Used Car Buyers: Checklist

Before proceeding with any used car purchase, run through this verification sequence using the plate number:

1. OneMotoring public search: Confirm registration date, COE expiry, vehicle make/model match listing
2. SMS check (74688): Quick road tax status verification
3. Vehicle history report: Third-party accident and insurance history (S$5–15)
4. Full log card review: Ask seller to show full log card including OMV, ARF, PARF, and encumbrances
5. Checksum verification (if concerned about plate legitimacy): Apply the formula above

Steps 1–3 cost nothing meaningful and take under 10 minutes. They catch the most common misrepresentations in used car listings. Step 4 requires the seller's cooperation — a seller who refuses to show the full log card is worth treating with significant caution.

For full guidance on evaluating a used car purchase in Singapore — including how to calculate PARF-adjusted pricing, model total ownership costs, and compare against COE renewal alternatives — see the Singapore COE Navigator.