How to round decimal value up to nearest 0.05 value?

Question

Is there any way to round up decimal value to its nearest 0.05 value in .Net?

Ex:

7.125 -> 7.15

6.66 -> 6.7

If its now available can anyone provide me the algo?

score 32 · Accepted Answer · edited Jul 18 '13 at 11:47

32

How about:

Math.Ceiling(myValue * 20) / 20

edited Jul 18 '13 at 11:47

Massimiliano Peluso

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answered Sep 19 '09 at 12:28

Adam Bellaire

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predator4: That seems to be what the OP wants, with the `6.66 -> 6.7` example. – caf Sep 19 '09 at 13:36
Sorry. Fair enough, I've missunderstood the round up thing. To reduce confusion I've deleted my comment. – user37325 Sep 19 '09 at 14:08
1

It should be noted that while this is a very good solution for the problem of rounding to arbitrary fractions, for decimal place rounding Math.Round should be used (just in case anyone comes looking at this question for a solution to more standard rounding). – ICR Sep 19 '09 at 14:32
8

Just as a warning, this can go wrong if the input is within a factor of 20 of the max value of a decimal (so, greater than about 4*10^27 for the decimal type). You can get around this by subtracting Math.floor, rounding the non-integer part, and then adding it back to the floor value. But since the original questioner's use is for a tax calculation, I doubt it matters unless it has to work in Zimbabwe... – Steve Jessop Sep 19 '09 at 14:33
@Steve, lol! and @predator4/user37325, your comment deletion only increased my confusion – Patrick McDonald Apr 29 '11 at 17:08
There is a flaw in this code that will cause rounding issues, trying the value 1.41 incorrectly yields 1.5 – Woot4Moo Jun 21 '13 at 21:35
9

A more straightforward way (and easier to change the round-to step) is to Math.Ceiling(myValue / 0.05) * 0.05 – Andriy Volkov Aug 15 '13 at 12:47

score 12 · Answer 2 · edited May 23 '17 at 10:30

12

Use this:

Math.Round(mydecimal / 0.05m, 0) * 0.05m;

The same logic can be used in T-SQL:

ROUND(@mydecimal / 0.05, 0) * 0.05

I prefer this approach to the selected answer simply because you can directly see the precision used.

edited May 23 '17 at 10:30

Community

1
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answered Jan 21 '11 at 14:49

Marc

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Math.Round doesn't allow to Round UP – Michael Freidgeim May 30 '13 at 07:57
0.5625 should be rounded up to .6 but it gives .55. best Math.Ceiling(myValue / 0.05) * 0.05. – Daniel B Nov 02 '18 at 19:41
Warning: this will only work if you want to round to multiples of 10. Consider the value 2671.875 and stepsize 50. I would expect the rounded value 2700. 2671.875/50 = 53.4375, which rounds to 53. But 53x50 = 2650. – Georg Patscheider Oct 25 '19 at 09:23

score 7 · Answer 3 · answered Aug 14 '13 at 00:42

7

Something like this should work for any step, not just 0.05:

private decimal RoundUp (decimal value, decimal step)
{
    var multiplicand = Math.Ceiling (value / step);
    return step * multiplicand;
}

answered Aug 14 '13 at 00:42

Andriy Volkov

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score 2 · Answer 4 · answered Feb 08 '10 at 05:53

2

Math..::.Round Method (Decimal, Int32, MidpointRounding)

Rounds a double-precision floating-point value to the specified number of fractional digits. A parameter specifies how to round the value if it is midway between two other numbers.

   Math.Round(1.489,2,MidpointRounding.AwayFromZero)

answered Feb 08 '10 at 05:53

Fredou

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MidpointRounding.AwayFromZero doesn't allow to Round UP -see http://msdn.microsoft.com/en-us/library/system.midpointrounding.aspx – Michael Freidgeim May 30 '13 at 07:56

score 0 · Answer 5 · answered Jun 16 '20 at 08:51

I could not get proper rounding in most of the formulas

This one "rounds" to nearest

float roundFloat(float value, float toNearest) {
            float divVal = (1 / (toNearest == 0 ? 1 : toNearest));
            return ((float)(Math.Round(value * divVal)) / divVal);
        }

Result:

roundFloat(2, 0.125F); -> 2
roundFloat(2.11, 0.125F); -> 2.125
roundFloat(2.22, 0.125F); -> 2.25
roundFloat(2.33, 0.125F); -> 2.375
roundFloat(2.44, 0.125F); -> 2.5
roundFloat(2.549999, 0.125F); -> 2.5
roundFloat(2.659999, 0.125F); -> 2.625
roundFloat(2.769999, 0.125F); -> 2.75
roundFloat(2.879999, 0.125F); -> 2.875
roundFloat(2.989999, 0.125F); -> 3

Example 0.125 nearest rounding

How to round decimal value up to nearest 0.05 value?

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