Cash ISA Calculator

Use our cash ISA calculator to see what your ISA could be worth in the future.

Cash ISA

from Plum

Interest Rate (AER) 5.17%
  • Term: Easy Access *Up to three withdrawals can be made within each 12-month without affecting the interest rate. More than three withdrawals made within each 12-month period, a lower rate of 3.00% (variable) will be applied
  • Invest From: £1
See Deal MARKET LEADING EASY ACCESS CASH ISA

Mobile App only account. *Includes a bonus of 0.88% AER (variable) if account held for 12 months. Transfer in any ISAs you hold with other providers. Interest rates drop if more than three withdrawals per year. Covered by FSCS. Rate when you transfer in your existing ISA – 4.29% AER (variable). Rate for each 12-month period after your first 12 months – 4.29% AER (variable). Rate when balance drops below £100 or after your fourth annual withdrawal – 3.00% AER (variable). Must be UK resident and be aged 18 or older

Limited Issue Online Easy Access Cash ISA

from Leeds Building Society

Interest Rate (AER) 4.75%
  • Term: Easy Access
  • Invest From: £1,000

Interest paid annually. Unlimited deposits and withdrawals. ISA transfers also allowed in. Open and manage online. FSCS Protected. Must be UK resident and be aged 18 or older

Cash ISA

from Moneybox

Interest Rate (AER) 4.75%
  • Term: Easy Access. *Up to three withdrawals can be made within each 12-month period from the date of opening without affecting the interest rate. More than three withdrawals made within each 12-month period, a lower rate of 0.75% (variable) will be applied
  • Invest From: £500

Mobile App only account. *The Moneybox Cash ISA includes a 4.25% AER variable underlying rate and a bonus rate of 0.50% for the first 12 months. Up to three withdrawals can be made within each 12-month period from the date of opening without affecting the interest rate. Transfer in any ISAs you hold with other providers into a Moneybox Cash ISA, entirely in-app. Covered by FSCS. If more than three withdrawals made within each 12-month period, a lower rate of 0.75% (variable) will be applied for the rest of that 12-month period. The lower interest rate of 0.75% will also apply if the account balance dips below £500, automatically returning to the higher interest rate when the balance returns to £500 or more again. Must be UK resident and be aged 18 or older

Easy Access Cash ISA

from Aldermore

Interest Rate (AER) 4.25%
  • Term: Easy Access
  • Invest From: £1,000

Interest paid monthly or annually. Unlimited deposits and withdrawals. ISA transfers also allowed in. Open and manage online. FSCS Protected. Must be UK resident and be aged 18 or older

30 Day Notice Cash ISA

from Aldermore

Interest Rate (AER) 4.50%
  • Term: Easy Access - 30 Day Notice
  • Invest From: £1,000

Unlimited deposits and withdrawals. ISA transfers in allowed. FSCS Protected. Must be UK resident and aged 16 or older. Withdrawals subject to 30 days notice

E-ISA Instant Access Cash ISA

from Leeds Building Society

Interest Rate (AER) 2.45%
  • Term: Instant Access
  • Invest From: £1

Low minimum deposit. Interest paid annually. Unlimited deposits and withdrawals. ISA transfers also allowed in. Open and manage online. FSCS Protected. Must be UK resident and be aged 18 or older

1 Year Fixed Rate Cash ISA

from Aldermore

Interest Rate (AER) 4.65%
  • Term: 1 Year
  • Invest From: £1,000

ISA transfers in allowed. FSCS Protected. Must be UK resident and aged 16 or older. Withdraw cash early if you need to (subject to loss of interest)

1 Year Fixed Rate Cash ISA

from Leeds Building Society

Interest Rate (AER) 4.65%
  • Term: 1 Year
  • Invest From: £100

Interest paid annually. ISA transfers also allowed in. Open online, in branch or by post. FSCS Protected. Must be UK resident and be aged 18 or older. Withdrawals permitted subject to 90 days lost interest

1 Year Fixed Rate ISA

from NatWest

Interest Rate (AER) 4.45% Tax Free p.a. (Fixed)
  • Term: 1 Year
  • Invest From: £1,000

Terms and Conditions: You must be 18 or over and a UK Resident. Currently you can only subscribe to one Cash ISA with NatWest Bank per tax year. Sole accounts only. Rate available until 5pm on 31/07/2024 for new customers and 05/08/2024 for existing customers. Offer may be withdrawn early due to limited availability. Interest is calculated daily and paid annually to your ISA on the first business day in April and on the Maturity Payment Date. If you want to make a withdrawal after this time and before the Maturity Date, you must close your account by giving written notice in branch. ISA subscription limits apply. If you make a payment into your Fixed Rate ISA you will not be able to make any further payments for that tax year into any other cash ISA with NatWest, except for a NatWest Help to Buy: ISA. Early Closure Charge applies. The Early Closure Charge will be the lower of the amount of interest earned on your account or 90 days’ interest. The Early Closure Charge will be deducted from the balance of your Fixed Rate ISA. The interest payable on the money held in your account is tax-free. The tax treatment may be subject to change in the future and depends on your individual circumstances.

1 Year Fixed Rate ISA

from Royal Bank of Scotland

Interest Rate (AER) 4.45% Tax Free p.a. (Fixed)
  • Term: 1 Year
  • Invest From: £1,000

Terms and Conditions: You must be 18 or over and a UK Resident. Currently you can only subscribe to one Cash ISA with RBS Bank per tax year. Sole accounts only. Rate available until 5pm on 14/08/2024 for new customers and 19/08/2024 for existing customers. Offer may be withdrawn early due to limited availability. Interest is calculated daily and paid annually to your ISA on the first business day in April and on the Maturity Payment Date. If you want to make a withdrawal after this time and before the Maturity Date, you must close your account by giving written notice in branch. ISA subscription limits apply. If you make a payment into your Fixed Rate ISA you will not be able to make any further payments for that tax year into any other cash ISA with Royal Bank of Scotland. Early Closure Charge applies. The Early Closure Charge will be the lower of the amount of interest earned on your account or 90 days’ interest. The Early Closure Charge will be deducted from the balance of your Fixed Rate ISA. The interest payable on the money held in your account is tax-free. The tax treatment may be subject to change in the future and depends on your individual circumstances.

2 Year Fixed Rate Cash ISA

from Leeds Building Society

Interest Rate (AER) 4.35%
  • Term: 2 Years
  • Invest From: £100

Interest paid annually. ISA transfers also allowed in. Open online, in branch or by post. FSCS Protected. Must be UK resident and be aged 18 or older. Withdrawals permitted subject to 180 days lost interest

2 Year Fixed Rate Cash ISA

from Aldermore

Interest Rate (AER) 4.30%
  • Term: 2 Years
  • Invest From: £1,000

ISA transfers in allowed. FSCS Protected. Must be UK resident and aged 16 or older. Withdraw cash early if you need to (subject to loss of interest)

2 Year Fixed Rate ISA

from NatWest

Interest Rate (AER) 4.10% Tax Free p.a. (Fixed)
  • Term: 2 Years
  • Invest From: £1,000

Terms and Conditions: You must be 18 or over and a UK Resident. Currently you can only subscribe to one Cash ISA with NatWest Bank per tax year. Sole accounts only. Rate available until 5pm on 31/07/2024 for new customers and 05/08/2024 for existing customers. Offer may be withdrawn early due to limited availability. Interest is calculated daily and paid annually to your ISA on the first business day in April and on the Maturity Payment Date. If you want to make a withdrawal after this time and before the Maturity Date, you must close your account by giving written notice in branch. ISA subscription limits apply. If you make a payment into your Fixed Rate ISA you will not be able to make any further payments for that tax year into any other cash ISA with NatWest, except for a NatWest Help to Buy: ISA. Early Closure Charge applies. The Early Closure Charge will be the lower of the amount of interest earned on your account or 90 days’ interest. The Early Closure Charge will be deducted from the balance of your Fixed Rate ISA. The interest payable on the money held in your account is tax-free. The tax treatment may be subject to change in the future and depends on your individual circumstances.

2 Year Fixed Rate ISA

from Royal Bank of Scotland

Interest Rate (AER) 4.10% Tax Free p.a. (Fixed)
  • Term: 2 Years
  • Invest From: £1,000

Terms and Conditions: You must be 18 or over and a UK Resident. Currently you can only subscribe to one Cash ISA with RBS Bank per tax year. Sole accounts only. Rate available until 5pm on 14/08/2024 for new customers and 19/08/2024 for existing customers. Offer may be withdrawn early due to limited availability. Interest is calculated daily and paid annually to your ISA on the first business day in April and on the Maturity Payment Date. If you want to make a withdrawal after this time and before the Maturity Date, you must close your account by giving written notice in branch. ISA subscription limits apply. If you make a payment into your Fixed Rate ISA you will not be able to make any further payments for that tax year into any other cash ISA with Royal Bank of Scotland. Early Closure Charge applies. The Early Closure Charge will be the lower of the amount of interest earned on your account or 90 days’ interest. The Early Closure Charge will be deducted from the balance of your Fixed Rate ISA. The interest payable on the money held in your account is tax-free. The tax treatment may be subject to change in the future and depends on your individual circumstances.

3 Year Fixed Rate Cash ISA

from Leeds Building Society

Interest Rate (AER) 4.15%
  • Term: 3 Years
  • Invest From: £100

Interest paid annually. ISA transfers also allowed in. Open online, in branch or by post. FSCS Protected. Must be UK resident and be aged 18 or older. Withdrawals permitted subject to 240 days lost interest

3 Year Fixed Rate Cash ISA

from Aldermore

Interest Rate (AER) 4.05%
  • Term: 3 Years
  • Invest From: £1,000

ISA transfers in allowed. FSCS Protected. Must be UK resident and aged 16 or older. Withdraw cash early if you need to (subject to loss of interest)

Cash ISA Calculator

Click here for ISA Calculator »

A cash Individual Savings Calculator is a program, mostly online, that helps you determine how much interest you could gain as interest on an ISA investment. While these tools only give a projection of the amount, they give valuable insight as to whether a certain interest rate is favorable and how much should be invested into the ISA regularly to give the best interest gains. A cash ISA calculator should not be used as the final determinant or decision maker when it comes to committing to a cash ISA. This is because it operates on assumptions to calculate a possible outcome on investment. That investment may gain more or less than estimated and is not an accurate measure.

Assumptions made on calculation

One of the assumptions made is that the individual will deposit money into the account on a regular basis. Cash ISAs give a lot of leeway when it comes to withdrawals and deposits. For that reason, it is not always necessary that an individual deposit money into the account on a regular basis in as long as the final tally on deposits does not exceed the cash ISA allowance limit.

Another assumption is that the market will be steady and the rates will be productive. Capital markets fluctuate all the time throughout the tax year. The market may grow or stunt considerably affecting the economical rates on conversion for the currency. Due to such changes therefore, the interest gained tends to fluctuate.

Another assumption made is that there shall be fixed tax rules throughout the duration of the tax year. The current tax allowance for ISAs exempts them from having to be taxed on interest made. However, the rules might change and in such a scenario, the tax rate could affect the projected figures.

It is also an assumption that there shall be no withdrawals made on the account. Most of the calculators work under the premise of compound interest. A withdrawal, which in reality will happen at one point or the other, has significant impact on interest.

Benefits of a cash ISA calculator

One of the benefits of using a cash ISA calculator is that it helps you predict your annual growth on a certain interest rate. From this prediction, you can then determine whether the interest rate offered is sufficient for your goals or whether you need to find a different rate elsewhere.

An ISA calculator also helps in determining how much money you should deposit on a regular basis, and at what time interval, to make it to the allowance limit, without having to compromise your financial situation.

Click here for ISA Calculator »