BAH by ZIP code

Choose the duty station ZIP rather than a housing search ZIP

For the ordinary locality BAH calculation, begin with the permanent duty station ZIP. The place where a member works, the installation mailing address, the home of record, and the address of a prospective rental can be different. A residential move does not by itself authorize changing the allowance to the rental property’s ZIP. The input should reflect the applicable duty basis, not a search for a larger rate.

Some assignments have authorized location exceptions, including certain dependent location arrangements. This guide does not decide whether an exception applies. If the orders, duty location, or family arrangement make the correct ZIP unclear, ask the servicing finance office before comparing amounts. A correct lookup for the wrong authorized location is still the wrong reference for the personal question you intended to answer.

Keep the ZIP as five characters

Leading zeros are part of a ZIP code. The retained 2026 mapping, for example, connects 02108 to MA120, BOSTON, MA. Writing that input as a number can lose its first character and produce 2108, which is not the same five character code. Keep the code as written in the official address rather than treating it as a quantity to round or shorten.

The calculator accepts the five digit ZIP rather than a street address, a city name, or a complete extended postal address. Confirm the base five digit code when your document displays a longer postal form. Check for an omitted zero, an extra character, or a transposed digit before concluding that the annual mapping lacks the intended duty location. Formatting and source coverage are separate checks.

Understand the ZIP to MHA to rate sequence

The published mapping connects each usable ZIP to an MHA code. Many ZIP codes can point to the same MHA, so two different input codes may legitimately produce the same area and amount. Conversely, sharing a city name, a state, or the first digits of a ZIP is not sufficient evidence that two codes share one housing area.

After the area is identified, the rate comes from that MHA’s selected grade and dependent category in the selected annual release. The website does not use a commercial rental estimate, a city average, or a ZIP prefix formula for that step. Read the MHA code and source label in the result so that another person can verify both the geographic mapping and the amount you selected.

Distinguish an unmatched code from a zero allowance

An unmatched input means that the current calculable index did not supply a supported area and amount for that code. It is not a determination that a member is owed zero. In the retained 2026 raw file, 214 ZIP rows map to XX499 UNKNOWN without corresponding rates. Those entries are deliberately excluded rather than assigned a neighboring area or an invented national average.

A supported format also does not turn an overseas location into an ordinary domestic locality lookup. Overseas assignments generally use Overseas Housing Allowance, or OHA; Alaska and Hawaii use BAH. Other assignment circumstances can require additional rules. When a code does not resolve, confirm the address and allowance type with the installation or finance office rather than repeatedly trying unrelated ZIPs until a result appears.

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Recognize a national rate entry

An MHA beginning with ZZ is a national rate entry rather than a specific local housing market. If the official mapping connects a supported ZIP to that entry, the calculator identifies the result accordingly. That is a genuine source match, different from a missing code and different from a local area named after an installation or city.

An unmatched ZIP is not automatically entitled to a ZZ amount. The website must have the published mapping and the rate entry before it can present that result. This prevents two different source situations from being blended into one fallback. The distinction also matters in a comparison: a national entry should not be described as a local rental market estimate for the unmatched address.

Treat a suggested area as a reference, not a corrected match

A reference area can help a user continue investigating a location, but it does not repair an absent ZIP mapping. Selecting a suggested MHA displays that area’s published amounts, not a rate authorized for the original unmatched code. Keep the reference label visible and verify the real duty station before using an amount in a personal decision.

The source files do not contain the coordinates or travel network needed to prove which MHA is geographically closest. A suggestion should therefore not be read as the nearest by road distance, straight line distance, commute time, or a journey across water. State or postal clues can organize a reference list; they cannot establish official mapping, geographic proximity, or entitlement.

Save the mapping year with the result

The current lookup uses 2026 mapping and rates, downloaded on November 13, 2026. Official 2027 data is pending here. December 2026 is an expected publication period from the usual annual pattern, not a confirmed release day or a reason to infer a new mapping. The website does not estimate 2027 amounts for a ZIP from an assumed percentage.

A shared result URL records the selected ZIP, grade, and dependent category, but the active source can change after a verified release. Save the year, download date, MHA, and displayed amount when a comparison needs a lasting record. Review those parameters before sharing a link publicly, because a public reference lookup can still reveal a person’s likely duty area, grade, and family category.