How HDBLens calculates every number

Source records

HDBLens combines the five official HDB resale transaction datasets into one normalised series from 1990-01 through 2026-08. It standardises flat-type labels and derives price per square metre and square foot from resale price and floor area.

Current and previous windows

The current market window is the latest 12 dataset months, ending 2026-08. Year-on-year figures compare it with the immediately preceding 12-month window. The latest month can be incomplete while registrations continue to arrive.

Medians

Price medians are calculated from the matching registered transactions. Price-per-area medians are calculated from each transaction's price per square metre rather than dividing two separate aggregate values.

Block comparables

The transaction explorer loads every public transaction for the exact block. Its 12-month block cards are grouped by flat type. No listing or asking price is mixed into the registered-sale dataset.

Valuation range

The valuation tool selects same-block, same-flat-type records with floor area within 18% or at least 10 square metres, prioritising the latest 36 months. If fewer than five records match, it broadens the area tolerance to 25% or 15 square metres and uses up to 30 block records. The centre is median price per square metre multiplied by the entered area; lower and upper values use the 25th and 75th percentiles.

Storey is used to label sample similarity, not to add an arbitrary floor premium. When the sample remains too weak, HDBLens returns no estimate.

Rental yield

Where an official town/flat-type median rent exists, gross yield is monthly median rent × 12 ÷ current resale median. It excludes vacancy, fees, tax, maintenance and financing.

Lease bands

Remaining lease is read from the transaction record where available and otherwise approximated from the lease commencement year and a 99-year term. Lease-band medians combine different property mixes and are not causal lease-decay estimates.

Rounding

Displayed currency values are rounded to whole Singapore dollars. Calculations use the unrounded underlying values. One square metre equals approximately 10.7639 square feet.

Limitations

Public transaction records do not capture renovation, interior condition, orientation, exact view, seller circumstances or every financing constraint. HDBLens is an independent research tool, not an official valuation or financial advice.