Want to know how much you should be putting into your pension fund?

The 13 million UK employees who don't have an occupational pension can now work out how much they need to save to guarantee a decent retirement income following today's launch of an online pension calculator.

The Trades Union Congress (TUC) has added the calculator to its http://www.workSMART.org.uk website, and hopes to highlight the inadequate provision many workers are making towards their retirement.

The workSMART Pension Calculator was developed by the Financial Services Authority (FSA) and the Association of British Insurers (ABI). The site also features a guide to pensions and their potential pitfalls.

Brendan Barber, TUC General Secretary Elect, said: "Most people at work will be shocked by the amount they need to save and how long they will have to work to get even a half-decent pension. Most will not be able to afford to save enough, and proposals to make students pay back their fees after they graduate will put even more pressure on younger employees, just as they should be starting to save for their retirement."

The TUC is lobbying the government to create a compulsory pensions system in which all employers would have to contribute 10 per cent of pay to their employees' pension funds. Employers would get the power to ensure workers, who can afford to, join their occupational schemes.

The number of employees with no access to a quality occupational pension is growing as employers retreat from providing final salary based schemes, and the numbers working for new and smaller businesses that make no pension provision has swelled, according to the TUC.

The Pension Calculator reveals that a 39 year-old woman wanting to pay £150 a month into a pension and to retire at 58 will receive a lump sum payment of £15,089 (max) and £38 per week thereafter. If she decides to retire at 63 instead she will receive a lump sum of £20,898 and a weekly payment of £59 (with further potential income from Basic and Additional state pension at 65).

A 25 year-old man wanting to pay £100 a month into a pension and to retire at 55 will receive a lump sum payment of £19,505 (max) and £45 a week thereafter. If he decides to retire at 65 he will receive a lump sum payment of £31,632 and a weekly payment of £93 plus £126 a week from the Basic and Additional state pension.

Joanne Segars, ABI Head of Pensions, said: "We are delighted to have the TUC's support for the Pension Calculator. This new partnership with the TUC will ensure that many more people are able to access meaningful, personalised information about their likely income in retirement."