Irish Calculators
Property

WAULT Calculator for Lease Expiry and Break Dates

Measure the remaining lease length of a property portfolio at your chosen valuation date. Use contractual dates and one consistent weighting basis; rent and area weighting measure different exposures.

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Your numbers

Each line: tenant, positive weight, lease expiry date, next exercisable break date. Use expiry again if there is no break.
Your figures stay on this device.

How the calculation works

WAULT summarises the remaining length of a portfolio of leases, giving greater influence to leases with larger weights. This calculator reports two horizons: contractual expiry and the next exercisable break. Choose whether the weights represent annual contracted rent or occupied area before entering the rows.

WAULT = sum(weight × remaining years) / sum(weight), calculated separately to expiry and the next exercisable break.

  1. Measure each remaining term

    The calculator counts actual calendar days from the assessment date to each expiry and break, then divides by 365. A leap day therefore contributes an additional day; whole calendar years are not substituted.

  2. Apply the chosen weights

    Each remaining term is multiplied by its row weight. Adding these products and dividing by the total weight produces a weighted average rather than a simple tenant average.

  3. Compare both lease horizons

    Read expiry WAULT alongside break WAULT. A shorter break horizon identifies an earlier possible interruption to the assumed lease duration, even where contractual expiries remain distant.

Worked example: Equal weights over 365-day years

Sample inputs demonstrate the method. They are not a forecast or product offer.

The example gives two leases equal rent weights of 100. From 1 January 2025, their expiries are one and two 365-day years away, so expiry WAULT is 1.5 years. Both next breaks are one year away, giving break WAULT of 1 year.

Valuation date
2025-01-01
Common weighting basis
Annual contracted rent
Lease weights and dates
A,100,2026-01-01,2026-01-01 B,100,2027-01-01,2026-01-01

Expected result

WAULT to expiry
1.5 years
WAULT to next break
1 years
Worked example: Different weights and a later break

Sample inputs demonstrate the method. They are not a forecast or product offer.

Valuation date
2025-01-01
Common weighting basis
Occupied area in one unit
Lease weights and dates
A,100,2026-01-01,2026-01-01 B,300,2027-01-01,2027-01-01

Expected result

WAULT to expiry
1.75 years
WAULT to next break
1.75 years

Understanding your result

The result is a portfolio duration in years, not a forecast that every tenant will remain until that date. An average also hides clustering: several large leases may end together even when the headline looks comfortable.

The model does not establish whether a break clause can legally be exercised or assess tenant credit quality. Supply dates that reflect the lease provisions and the assessment purpose.

Questions you might have

Which break date belongs in the table?

Use the next break that is still exercisable under the lease. If none remains, enter the expiry date in both date columns.

Choosing the right inputs

Valuation date
Use one assessment date for the entire portfolio. Each expiry must be later than that date; a next break may fall on the assessment date but cannot precede it or follow expiry.
Common weighting basis
Select a consistent weighting basis. Rent weighting describes exposure to contracted income; area weighting describes exposure to occupied space. The selector labels your basis and does not convert the row values.
Lease weights and dates
Enter tenant, positive weight, expiry date and next break date on each row. If there is no break, repeat the expiry date. Review historical break dates against the actual lease position before entering them.

Common mistakes to avoid

  • Do not mix annual rent for one tenant with floor area for another.
  • Do not leave an already elapsed break in the data merely because it appears in the original lease.

Assumptions to check

  • Rent weighting and area weighting describe different exposures; do not mix them in one list.

Sources and method

Read our calculation and testing approach.