Military Leave Accrual Calculator

Understanding Military Leave Accrual

Paid leave is one of the most important benefits of U.S. military service. Active duty members earn vacation days at a steady pace throughout the year, which supports rest, family time, and recovery from deployments. Leave is more than a simple perk—it is a regulated entitlement governed by federal law and service-specific regulations.

Knowing how much leave you have earned, how much you have already used, and how much you might lose at the end of the fiscal year helps you:

• Plan annual leave, block leave, and family trips
• Schedule PCS moves and training with less stress
• Avoid forfeiting “use or lose” days at fiscal year end

This calculator provides a simplified estimate of your ordinary leave balance based on your service dates, days of leave used, and any days carried over from the previous fiscal year. It is designed as a planning aid and does not replace your official Leave and Earnings Statement (LES) or guidance from your finance or personnel office.

How Military Leave Accrues

Under normal conditions, active duty service members earn ordinary leave at a rate of 2.5 days per month of active service, for a total of 30 days of leave per year. Accrual rules are set by federal statute and Department of Defense policy, then implemented by each service branch.

In simple terms:

• Accrual rate: 2.5 days of leave per month of active duty
• Typical annual total: 30 days per full year of service
• Standard carryover cap: 60 days at the end of the fiscal year (absent special leave accrual or temporary policy changes)

Leave is normally tracked in whole and half days, and is charged when you are away from duty in a status where leave is required. Some types of absence, such as passes or certain non-chargeable periods, may not reduce your leave balance; those special cases are not modeled by this calculator.

Formula Used by This Calculator

The calculator uses a straightforward approximation to estimate your leave balance. It assumes you accrue leave at 2.5 days per month during the period between your selected start date and as-of date.

The key variables are:

• L = estimated leave balance (days)
• m = number of months served between the start date and as-of date (approximate)
• U = days of leave used during that period
• C = days of leave carried over from the previous fiscal year

The base formula is:

L = 2.5 × m + C − U

In MathML form, this can be represented as:

Because leave accrues on a monthly schedule and partial months can generate partial days of leave, this tool:

• Approximates the number of months by dividing the total days between your dates by 30
• Calculates leave earned as 2.5 times that approximate month count
• Rounds the result to the nearest half day for easier planning

Fiscal Year, Carryover, and Use-or-Lose Leave

Military leave accounting follows the federal fiscal year, not the calendar year. The fiscal year runs from 1 October through 30 September of the following year.

At the end of the fiscal year (30 September):

• Most members may carry forward up to 60 days of leave into the new fiscal year.
• Any days above that limit are normally classified as use or lose and will be lost if not taken by 30 September.

For example, if your estimated balance on 30 September is 72 days and no special exception applies, only 60 days carry into the new fiscal year. The remaining 12 days would be use-or-lose, meaning you must take them before the fiscal year ends or forfeit them.

This calculator helps you approximate:

• Your total earned leave for a given period
• Your estimated current balance after subtracting days used
• Whether your projected balance is approaching the standard 60-day cap at fiscal year end

Sample Accrual Table

The table below illustrates how quickly leave can accumulate using the standard 2.5 days per month rate, assuming continuous service and no leave taken.

After two full years (24 months) of continuous service with no leave taken, you would earn about 60 days of leave, which aligns with the typical maximum that can be carried over at the end of the fiscal year without special authorization.

Worked Example

The following example shows how to interpret the calculator’s inputs and results.

Scenario: You entered active duty on 1 January, and today’s date (your as-of date) is 30 September of the same year. You have used 10 days of leave and carried 5 days over from the previous fiscal year.

1. Determine the time period.
   From 1 January to 30 September is approximately 9 months of active duty.

2. Estimate months served.
   The tool calculates the exact number of days between the start and as-of dates, then divides by 30 to approximate months. For this example we will assume it results in about 9 months.

3. Calculate leave earned.
   Leave earned ≈ 2.5 days per month × 9 months = 22.5 days.

4. Add carried-over leave.
   You started the fiscal year with C = 5 days carried over.

5. Subtract used leave.
   You used U = 10 days of leave during this period.

Using the formula:

L = 2.5 × 9 + 5 − 10 = 22.5 + 5 − 10 = 17.5 days

The calculator would then round this to the nearest half day (in this case, 17.5 days). You could expect your estimated current balance to be about 17.5 days of leave.

How to interpret this:

• You likely have enough leave for a two-week trip, if approved by your chain of command.
• You are well below the standard 60-day cap, so you do not appear at risk of losing leave at this point in the fiscal year.
• You should still confirm your exact balance on your LES before making financial commitments (for example, nonrefundable travel bookings).

Comparison: Calculator Estimate vs. Official Leave Accounting

The table below compares how this tool estimates your leave versus how your service branch’s official systems track it. This can help you understand why your results may not exactly match your LES.

Special Leave Accrual and Higher Maximums

In some situations, service members can carry more than the standard 60 days of leave into a new fiscal year under a program commonly referred to as Special Leave Accrual (SLA). SLA is typically associated with:

• Lengthy deployments or contingency operations
• Assignments where operational tempo makes taking leave difficult
• Certain stop-loss or mobilization scenarios

When SLA is approved and properly documented, members may temporarily carry up to 120 days of leave, subject to strict rules on how long that extra leave may be retained. The precise criteria, maximums, and expiration timelines are defined in Department of Defense guidance and service-specific regulations, and they can change over time.

This calculator does not attempt to model SLA eligibility or temporary higher caps. If you are in a unit or assignment where SLA may apply, consult your chain of command, S1, admin, or finance office to understand how it affects your personal leave balance and any deadlines for using SLA leave before it expires.

Interpreting Your Results

When you run the calculator, you will see an estimated leave balance based on the inputs you provided. You can think about the result in three parts:

1. Estimated current balance.
   This is the number of days the tool predicts you have available as of your selected date, after factoring in carried-over days and days used. If the value is negative, it may indicate you entered more days of leave used than you likely earned in that period.

2. Progress toward the cap.
   If your estimated balance is approaching or above 60 days, you may be at risk of hitting the standard carryover limit at fiscal year end. In that case, talk with your supervisor early about scheduling leave to avoid losing days.

3. Planning implications.
   Use the estimate as a starting point when considering block leave, holidays, or major life events (such as a move, wedding, or birth of a child). Always confirm the exact balance on your LES before finalizing travel plans.

Assumptions and Limitations

This calculator is intentionally simplified. It is designed to provide a quick estimate rather than reproduce every detail of official leave accounting. Keep the following assumptions and limitations in mind:

• Standard active-duty accrual only. The tool assumes the standard rate of 2.5 days of ordinary leave per month of active duty. It does not differentiate among officer/enlisted or service branches for accrual rate.
• Approximate month length. Months are approximated as 30 days for calculation purposes. This may cause small differences compared to systems that use exact calendar months.
• Rounding to half days. Results are rounded to the nearest half day. Official records may use slightly different rounding rules or track more precise fractions of a day.
• No automatic SLA modeling. Special Leave Accrual, higher caps, and temporary policy changes are not automatically included. If you are covered by an SLA authorization, your real maximum may be higher than the standard 60-day cap used here.
• Simplified treatment of leave used. The “Days of Leave Used” input treats all days as chargeable ordinary leave. Non-chargeable leave categories, passes, and other special cases are not distinguished.
• Accession and separation nuances. The calculator does not account for the fine details of joining or leaving service mid-month, breaks in active service, or changes in status (such as transitioning between active and reserve components).
• Active duty focus. The logic is tailored to continuous active duty service. Drilling Reserve and Guard members with intermittent active duty periods may see larger gaps between this estimate and their official records.
• No official status. This tool does not create, modify, or access any official records. Your LES and your service’s finance and personnel systems are the only authoritative sources for your leave balance.

Because of these limitations, always verify important decisions—such as terminal leave planning, major trips, or separation timelines—with your chain of command and your official records.

Practical Tips for Using This Calculator

• Use your actual active duty start date or the date marking the beginning of the period you care about (for example, the start of the current fiscal year).
• Enter carried-over days as the balance you brought into the current fiscal year, not including any days you have earned since.
• Count days of leave used as the number of chargeable leave days you believe you have taken during the selected period. Exclude passes or non-chargeable periods if you know they did not reduce your leave balance.
• Check your latest LES to see how close this estimate is to your official balance, then adjust your inputs if needed for a better match.

Used thoughtfully, this tool can help you watch your leave balance grow, avoid losing hard-earned days at the end of the fiscal year, and plan time off that supports both mission requirements and your personal life.