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copied!<p>To answer a slightly different question: <em>don't</em> use the float type to represent currency values. <a href="http://www.javapractices.com/topic/TopicAction.do?Id=13" rel="noreferrer">It will bite you</a>. Use a base-10 type instead, like <code>BigDecimal</code>, or an integer type like <code>int</code> or <code>long</code> (representing the quantum of your value - penny, for example, in US currency).</p> <p>You will not be able to store an exact value - 123.45, say, as a float, and mathematical operations on that value (such as multiplication by a tax percentage) will produce rounding errors.</p> <p>Example from that page: </p> <pre><code>float a = 8250325.12f; float b = 4321456.31f; float c = a + b; System.out.println(NumberFormat.getCurrencyInstance().format(c)); // prints $12,571,782.00 (wrong) BigDecimal a1 = new BigDecimal("8250325.12"); BigDecimal b1 = new BigDecimal("4321456.31"); BigDecimal c1 = a1.add(b1); System.out.println(NumberFormat.getCurrencyInstance().format(c1)); // prints $12,571,781.43 (right) </code></pre> <p>You don't want to muck with errors when it comes to money.</p> <p>With respect to the original question, I haven't touched Java in a little while, but I know that I'd like to stay away from regex to do this kind of work. I see this recommended; it may help you. Not tested; caveat developer.</p> <pre><code>try { String string = NumberFormat.getCurrencyInstance(Locale.GERMANY) .format(123.45); Number number = NumberFormat.getCurrencyInstance(locale) .parse("$123.45"); // 123.45 if (number instanceof Long) { // Long value } else { // too large for long - may want to handle as error } } catch (ParseException e) { // handle } </code></pre> <p>Look for a locale with rules that match what you expect to see. If you can't find one, use multiple sequentially, or create your own <a href="http://www.exampledepot.com/egs/java.text/FormatNum.html" rel="noreferrer">custom NumberFormat</a>.</p> <p>I'd also consider forcing users to enter values in a single, canonical format. 123.45 and 123.456 look <em>way</em> too similar for my tastes, and by your rules would result in values that differ by a factor of 1000. <a href="http://blogs.msdn.com/oldnewthing/archive/2009/06/08/9705184.aspx" rel="noreferrer">This is how millions are lost</a>.</p>

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