What is vendor comparison?
Vendor comparison is the process of judging supplier offers against the same requirements before you buy. Compare on price alone when offers are truly equal in spec, delivery and terms. Use a weighted score when quality, delivery or service differ. In Singapore, also check each vendor's GST status and tax invoice before you approve.
Think of it like choosing a contractor to renovate your flat. The cheapest quote looks good until you learn it excludes hacking works. A fair comparison puts every quote on the same footing first. Only then does the price tell you something useful.
This guide is for procurement managers, finance teams and SME owners. It covers the following topics.
- When price-only comparison works and when it misleads.
- How to build a weighted scorecard that holds up to audit.
- Two worked S$ examples with real arithmetic.
- Singapore checks on GST, tax invoices and InvoiceNow.
- A decision table and a checklist with red flags.
Price-only vs weighted comparison at a glance
There are two main methods. Each suits a different kind of purchase. Pick the method before you open the quotes, not after.
| Factor | Price-only comparison | Weighted evaluation |
|---|---|---|
| Best for | Standard items with identical specs | Items where quality or delivery matter |
| Inputs | Total landed cost per offer | Scores for price, quality, delivery and service |
| Speed | Fast | Slower, needs agreed weights |
| Main risk | Ignores hidden costs and late delivery | Weights can be bent to favour a vendor |
| Typical use | Copier paper, cleaning supplies, cartons | Machine parts, IT services, logistics |
Start every comparison with pass or fail checks. An offer that fails a must-have rule is out, whatever its price. Examples include the wrong spec, a missing certificate or a delivery date you cannot accept.
A Changi logistics firm buying pallet wrap shows the point. Two quotes meet the spec and deliver in three days. Price-only comparison is fine here. A third quote with a 21-day lead time fails the delivery rule and is dropped.
Normalise offers before you compare
Quotes rarely arrive in the same shape. One vendor quotes per carton and another per piece. One includes delivery and another charges it separately. You must convert them to the same basis first.
Normalising is like converting recipes to the same unit. You cannot compare 2 cups with 500 grams until you convert one of them. Check these items on every quote.
- Unit of measure and pack size.
- Currency, plus the exchange rate you will use.
- Whether prices are before or after GST.
- Delivery, installation and handling charges.
- Payment terms, such as 30 or 60 days.
- Validity period of the offer.
Total landed cost is the full cost to get the item to your door. It includes the unit price, freight, duties and handling. Compare landed cost, not the headline price.
A seven-step vendor comparison process
A repeatable process keeps comparisons fair and fast. It also makes audits easier, because every award follows the same path. Use these seven steps for any significant purchase.
- Write the requirement. State the spec, quantity, delivery date and site.
- Set the must-haves. List the pass or fail rules, such as certificates or lead time.
- Choose the method. Decide on price-only or weighted, and fix any weights.
- Invite quotes. Send the same RFQ to every vendor with the same deadline.
- Normalise offers. Convert each quote to landed cost on the same GST basis.
- Score and rank. Apply the pass or fail rules first, then price or weights.
- Approve and record. A second person approves, and the reasons are kept on file.
Step four is where many teams slip. If one vendor gets extra details by phone, the comparison is no longer fair. Send any clarification to every vendor at the same time.
Take a Woodlands electronics assembler sourcing cable harnesses. It sends one RFQ to four vendors with a ten-day deadline. One vendor asks about pin layout, so the answer goes to all four. The final ranking is then easy to defend.
Who should take part in the comparison
Vendor comparison works best as a team effort. Each role sees a different part of the risk. Keep the group small so decisions stay quick.
| Role | What they check |
|---|---|
| Requester | The spec and the delivery date |
| Procurement | Quotes, terms and the comparison method |
| Finance | Budget, payment terms and GST details |
| Quality or engineering | Technical fit and supplier certificates |
| Approver | That the process was followed |
Separating these roles is like having a referee in a football match. The players play, and someone else checks the rules. It protects both the buyer and the business.
Worked S$ example where the lowest price costs more
Here is an illustrative case. A Bedok bakery chain needs 2,000 food-grade boxes a month. Three vendors quote. All meet the food-safety spec.
| Item | Vendor A | Vendor B | Vendor C |
|---|---|---|---|
| Unit price | S$0.40 | S$0.43 | S$0.45 |
| Boxes per month | 2,000 | 2,000 | 2,000 |
| Goods cost | S$800 | S$860 | S$900 |
| Delivery per month | S$120 | S$40 | Included |
| Expected rejects | 3 % (S$24) | 1 % (S$8.60) | 1 % (S$9) |
| Monthly landed cost | S$944 | S$908.60 | S$909 |
Vendor A has the lowest unit price. Yet after delivery and rejects, it costs the most each month. Vendor B is the cheapest on a landed basis by a small margin. All figures are before GST.
Over a year, Vendor A costs S$424.80 more than Vendor B. That gap is small per box but real in total. Read our guide to quotation letters to see what each quote should state.
Worked scorecard where delivery changes the decision
Now a case where price is not the whole story. A Tuas precision engineering firm buys spindle bearings. A late part stops a production line. The team uses a weighted scorecard.
The weights are agreed before quotes arrive. Price counts for 40 %, quality for 30 %, delivery for 20 % and service for 10 %. Each vendor is scored from 1 to 5 per factor.
| Factor (weight) | Vendor X | Vendor Y |
|---|---|---|
| Price (40 %) | 5 (S$18,000) | 4 (S$19,500) |
| Quality (30 %) | 3 | 5 |
| On-time delivery (20 %) | 2 | 5 |
| Service (10 %) | 3 | 4 |
| Weighted score | 3.60 | 4.50 |
Vendor X is S$1,500 cheaper. But its weak quality and delivery scores pull it down. Vendor Y wins with 4.50 against 3.60. One missed delivery could cost the firm far more than S$1,500 in lost output.
Notice how the weights drive the result. Suppose price counted for 70 % and the other three for 10 % each. Vendor X would then win, 4.30 against 4.20. That is why the weights must reflect real business risk.
Base delivery and quality scores on records, not memory. Use on-time delivery rates and reject rates from past orders. This keeps the scorecard fair and defensible.
Decision table for choosing the method
Use this table to pick a method quickly. Match your purchase to the closest row. When in doubt, choose the weighted method.
| Your situation | Method | Why |
|---|---|---|
| Identical specs and delivery, low value | Price-only | Differences are only in price |
| Identical specs, different delivery charges | Price-only on landed cost | Freight changes the real price |
| A late or faulty item stops operations | Weighted | Delivery and quality carry real risk |
| Ongoing service contract | Weighted | Service quality matters over time |
| Valid agreed price already exists | No new comparison | Use the pricelist or blanket order |
| Large or public tender | Formal tender with set weights | Needs a clear audit trail |
The last two rows matter most for saving time. If you already hold a valid agreed price, a fresh comparison adds little. Our guide to vendor pricelist management in Singapore covers that route.
Singapore checks before you approve a vendor
Price and score are not the only tests. Singapore tax rules affect what an offer really costs you. Run these checks before you approve.
First, check whether the vendor is GST-registered. GST is 9 % in Singapore. A GST-registered buyer can usually claim GST on purchases as input tax. That claim needs a valid tax invoice from a GST-registered supplier.
So compare offers on the same GST basis. If one vendor is not GST-registered, it will not charge GST. For a GST-registered buyer that can claim input tax, this makes little difference. For a buyer that cannot claim, the unregistered vendor may be cheaper overall.
Next, confirm the vendor's legal identity. Every Singapore company has a Unique Entity Number, or UEN. Record it on the vendor master. You will also need it for InvoiceNow, Singapore's e-invoicing network run by IMDA.
IRAS is phasing in a GST InvoiceNow Requirement for GST-registered businesses. Ask each vendor whether it can send InvoiceNow invoices. Structured invoices are easier to check against your PO.
Common vendor comparison mistakes
Most poor vendor choices come from a handful of habits. They are easy to spot once you know them. Here are the ones we see most often.
- Comparing unit prices when pack sizes differ.
- Forgetting delivery, installation or handling charges.
- Scoring quality from memory instead of reject records.
- Letting the requester pick the vendor and then backfilling quotes.
- Re-running a full comparison for items with a valid agreed price.
Backfilled quotes are the most serious problem. They make the process look fair when it is not. A Jurong Island chemicals distributor found this in an internal audit. It now requires quotes to arrive before any vendor is named.
Vendor comparison checklist with red flags
Use this checklist on every significant purchase. Each row shows a good answer and a red flag. Any red flag deserves a second look.
| Check | Good answer | Red flag |
|---|---|---|
| Requirements set | Specs and must-haves agreed before quotes | Specs change after quotes arrive |
| Same basis | All offers normalised to landed cost | Headline prices compared directly |
| Weights fixed | Weights agreed and recorded upfront | Weights adjusted after scoring |
| Evidence | Scores backed by delivery and reject data | Scores based on opinion |
| Enough offers | At least three valid quotes for large buys | One quote with no reason recorded |
| Tax details | GST status and UEN confirmed | Vendor cannot give a GST number |
| Approval | Approver differs from the buyer | Buyer approves their own choice |
The weights row is the one auditors check first. Changing weights after scoring is like moving the goalposts mid-match. Lock them in writing before quotes arrive.
How HashMicro supports vendor comparison
HashMicro's procurement and purchasing management system offers two ways to compare vendors. The quick way is Compare RFQ. The formal way is Purchase Tender.
With Compare RFQ, you select two or more open RFQs that share at least one product. Purchase orders, cancelled RFQs and rejected RFQs do not qualify. You then confirm the winning quote into a PO from the RFQ Comparison screen. Make sure each RFQ covers the same spec and quantity first.
Purchase Tender suits formal, multi-vendor bidding. The flow is outlined below.
- Pre-qualify vendors for the category.
- Create a tender, invite vendors and collect bids.
- Award by the strategy set in Award Strategy Config, such as price or score.
- Turn awarded bids into purchase orders.
For the evidence side, vendor performance templates score suppliers on delivery, quality and price. Evaluations run per period. A Supplier Performance dashboard shows scores and spend together. Use these scores in your next weighted comparison.
See how it works with your own vendors. Book a demo and bring three real quotes for the same item. Ask the team to compare them and confirm the winner into a PO.
Frequently asked questions
How many quotes should we compare?
Three valid quotes is a common rule for significant purchases. Small, low-risk buys may need fewer. Record a reason whenever you accept a single quote.
What weights should a vendor scorecard use?
There is no universal set. Price often carries 30 % to 50 %. Raise quality and delivery weights when failure would stop your operations.
Should we compare prices before or after GST?
Compare on the same basis for every offer. GST-registered buyers that can claim input tax usually compare before GST. Buyers that cannot claim should compare the total after GST.
Is the lowest price always the best choice?
No, not always. Delivery charges, rejects and late deliveries can make a cheap offer expensive. Compare total landed cost and risk, not unit price alone.
How do we compare vendors quoting in different currencies?
Convert every offer to S$ at one agreed exchange rate. Record the rate and the date you used. Add a buffer for currency risk on long contracts, as rates can move before you pay.
When should we run a formal tender?
Run a tender for large, complex or high-risk purchases. It gives every vendor the same rules and timeline. It also leaves a clear audit trail for each award.
For more on choosing suppliers, read our guides to supplier selection and tender projects. Both explain the steps around a vendor comparison.
