# Convert fJ to Ha (Femtojoule to Hartree)

- Choose the right category from the selection list, in this case 'Energy'.
- Next enter the value you want to convert. The basic operations of arithmetic: addition (+), subtraction (-), multiplication (*, x), division (/, :, ÷), exponent (^), square root (√), brackets and π (pi) are all permitted at this point.
- From the selection list, choose the unit that corresponds to the value you want to convert, in this case 'Femtojoule [fJ]'.
- Finally choose the unit you want the value to be converted to, in this case 'Hartree [Ha]'.
- Then, when the result appears, there is still the possibility of rounding it to a specific number of decimal places, whenever it makes sense to do so.

### Utilize the full range of performance for this units calculator

With this calculator, it is possible to enter the value to be converted together with the original measurement unit; for example, '493 Femtojoule'. In so doing, either the full name of the unit or its abbreviation can be usedas an example, either 'Femtojoule' or 'fJ'. Then, the calculator determines the category of the measurement unit of measure that is to be converted, in this case 'Energy'. After that, it converts the entered value into all of the appropriate units known to it. In the resulting list, you will be sure also to find the conversion you originally sought. Alternatively, the value to be converted can be entered as follows: '52 **fJ to Ha**' or '31 **fJ into Ha**' or '28 **Femtojoule -> Hartree**' or '4 **fJ = Ha**' or '79 **Femtojoule to Ha**' or '55 **fJ to Hartree**' or '7 **Femtojoule into Hartree**'. For this alternative, the calculator also figures out immediately into which unit the original value is specifically to be converted. Regardless which of these possibilities one uses, it saves one the cumbersome search for the appropriate listing in long selection lists with myriad categories and countless supported units. All of that is taken over for us by the calculator and it gets the job done in a fraction of a second.

Furthermore, the calculator makes it possible to use mathematical expressions. As a result, not only can numbers be reckoned with one another, such as, for example, '(85 * 61) fJ'. But different units of measurement can also be coupled with one another directly in the conversion. That could, for example, look like this: '34 Femtojoule + 10 Hartree' or '37mm x 13cm x 88dm = ? cm^3'. The units of measure combined in this way naturally have to fit together and make sense in the combination in question.

The mathematical functions sin, cos, tan and sqrt can also be used. Example: sin(π/2), cos(pi/2), tan(90°), sin(90) or sqrt(4).

If a check mark has been placed next to 'Numbers in scientific notation', the answer will appear as an exponential. For example, 1.000 422 706 945 5×1022. For this form of presentation, the number will be segmented into an exponent, here 22, and the actual number, here 1.000 422 706 945 5. For devices on which the possibilities for displaying numbers are limited, such as for example, pocket calculators, one also finds the way of writing numbers as 1.000 422 706 945 5E+22. In particular, this makes very large and very small numbers easier to read. If a check mark has not been placed at this spot, then the result is given in the customary way of writing numbers. For the above example, it would then look like this: 10 004 227 069 455 000 000 000. Independent of the presentation of the results, the maximum precision of this calculator is 14 places. That should be precise enough for most applications.