Savings reserve calculator

The calculator uses the numbers you enter: liquid savings, monthly fixed costs, and the reserve months you set. 6,200 at 2,900 with a 3-month target is 2.1 months of reserve, or 0.9 months below the target. Delay days and income sources sit in the grid. Income swing is optional and does not change the main result.

This compares reserve months with a target you set. How many months savings last on their own is on the emergency fund page. The calculator does not connect to a bank.

Input data

Enter savings, fixed costs, and the reserve months you set. Delay days and income sources sit in the grid. You can skip income swing.

Optional context

This field is optional. Income swing appears in the grid beside the reserve months. A blank field skips that context and does not change the main result.

Results

Enter data and click Calculate.

How it works

The calculator divides liquid savings by monthly fixed costs. It subtracts the reserve months you set from that count. 6,200 at 2,900 with a 3-month target is 2.1 months of reserve, or 0.9 months below the target.

The main result comes from three fields: savings, fixed costs, and the target. Delay days in the quarter and the number of income sources sit in the grid: they show fixed costs for those days and do not change the gap versus the target. Income swing is optional.

Second example: 12,000 at 2,400 with a 4-month target is 5 months of reserve, or 1 month above the target. Third example: 2,000 at 3,500 with a 3-month target is 0.6 months of reserve, or 2.4 months below the target.

The calculator does not connect to a bank and is not investment advice. How many months savings last on their own, without a target gap, is on the emergency fund page. A comma in 12.5 is read the same way as a period.

Formula

Reserve months = savings ÷ fixed costs. Main result = that count minus the months you set. At 6,200, 2,900 and a 3-month target: 2.1 − 3 = 0.9 months below the target. Delay days and income sources sit in the grid. Income swing is optional.

What these numbers mean

6,200 at 2,900 with a 3-month target is 2.1 months of reserve, or 0.9 months below the target.

reserve months
Liquid savings divided by fixed costs. 6,200 ÷ 2,900 = 2.1 months.
target
The months you set for yourself. The reserve is subtracted from this number. At a target of 3, the gap is 0.9 months.
payment delays
Days in the quarter that income is late. They show fixed costs for those days in the grid and do not change the gap versus the target.

How to use

  1. Enter savings 6,200, fixed costs 2,900, and a 3-month target.
  2. Add 5 delay days in the quarter and 2 income sources. Those numbers stay in the grid.
  3. Click Calculate. The result is 0.9 months below the target.
  4. Second example: 12,000, 2,400 and a 4-month target is 1 month above the target. Third: 2,000, 3,500 and a 3-month target is 2.4 months below the target.
  5. You can skip income swing. When you fill it, it appears in the grid and does not change the main result.

Examples

Example 1

  • savings 6200
  • fixed 2900
  • target 3 mo
  • delays 5
  • sources 2

0.9 months below the reserve you set

6,200 divided by 2,900 is 2.1 months versus a 3-month target. Result: 0.9 months below the reserve.

Example 2

  • savings 12000
  • fixed 2400
  • target 4 mo
  • delays 0
  • sources 3

1 month above the reserve you set

12,000 divided by 2,400 is 5 months versus a 4-month target. Result: 1 month above the reserve.

Example 3

  • savings 2000
  • fixed 3500
  • target 3 mo
  • delays 20
  • sources 1

2.4 months below the reserve you set

2,000 divided by 3,500 is 0.6 months versus a 3-month target. Result: 2.4 months below the reserve.

Related calculators

Emergency fund calculator

How many months savings last on their own, without a target gap.

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Yearly cost of late fees and other fees: 1 late payment at 20 a quarter and 38 a month is 536 this year.

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Common questions

What does 0.9 months below the target mean?

6,200 divided by 2,900 is 2.1 months of reserve. The target is 3, so the gap is 0.9 months below the target.

How is the result calculated?

Reserve months = savings divided by fixed costs. The main result is that count minus the months you set.

What is the second example?

12,000 at 2,400 with a 4-month target is 5 months of reserve, or 1 month above the target.

What is the third example?

2,000 at 3,500 with a 3-month target is 0.6 months of reserve, or 2.4 months below the target.

How is this different from the emergency fund page?

Here the result is the gap versus a target you set. On the emergency fund page the result is how many months savings last on their own.

Do all fields enter the main result?

No. The main result comes from savings, fixed costs, and the target. Delay days and income sources sit in the grid. Income swing is optional.

What do reserve, target, and delays mean?

Reserve is savings divided by fixed costs. Target is the months you set. Delays show fixed costs for those days in the grid and do not change the gap.

Does a comma in 12.5 work?

Yes. 12.5 and 12,5 are read the same way.

Sources

The result comes from the numbers you enter. This compares reserve months with a target. It is not investment advice and does not connect to a bank.

Page updated in 2026.