To calculate your aspect ratio decimal, divide the resolution's width by its height. Note that ultra-widescreen is marketed as 21:9 but the aspect ratio actually varies slightly between resolutions (these are listed separately below).
| Common Name | Decimal | Formatted Value |
| 5:4 | 1.25 | 00 00 A0 3F |
| 4:3 | 1.33 | AB AA AA 3F |
| 3:2 | 1.5 | 00 00 C0 3F |
| 16:10 | 1.6 | CD CC CC 3F |
| 15:9 | ~1.66 | 55 55 D5 3F |
| 16:9 | ~1.77 | 39 8E E3 3F |
| 1.85:1 | 1.85 | CD CC EC 3F |
| 21:9 (2560x1080) | ~2.37 | 26 B4 17 40 |
| 21:9 (3440x1440) | ~2.38 | 8E E3 18 40 |
| 2.39:1 | 2.39 | C3 F5 18 40 |
| 21:9 (3840x1600) | 2.4 | 9A 99 19 40 |
| 2.76:1 | 2.76 | D7 A3 30 40 |
| 32:10 | 3.2 | CD CC 4C 40 |
| 32:9 | ~3.55 | 39 8E 63 40 |
| 3x5:4 | 3.75 | 00 00 70 40 |
| 3x4:3 | 4 | 00 00 80 40 |
| 3x16:10 | 4.8 | 9A 99 99 40 |
| 3x15:9 | 5 | 00 00 A0 40 |
| 3x16:9 | ~5.33 | AB AA AA 40 |
| Value | Hex Value |
Formatted Value | |
| 200 | 0x0C8 | C800 | |
| 240 | 0x0F0 | F000 | |
| 320 | 0x140 | 4001 | |
| 480 | 0x1E0 | E001 | |
| 525 | 0x20D | 0D02 | |
| 540 | 0x21C | 1C02 | |
| 576 | 0x240 | 4002 | |
| 600 | 0x258 | 5802 | |
| 640 | 0x280 | 8002 | |
| 704 | 0x2C0 | C002 | |
| 720 | 0x2D0 | D002 | |
| 768 | 0x300 | 0003 | |
| 800 | 0x320 | 2003 | |
| 840 | 0x348 | 4803 | |
| 848 | 0x350 | 5003 | |
| 854 | 0x356 | 5603 | |
| 900 | 0x384 | 8403 | |
| 960 | 0x3C0 | C003 | |
| 992 | 0x3E0 | E003 | |
| 1000 | 0x3E8 | E803 | |
| 1024 | 0x400 | 0004 | |
| 1050 | 0x41A | 1A04 | |
| 1080 | 0x438 | 3804 | |
| 1152 | 0x480 | 8004 | |
| 1200 | 0x4B0 | B004 | |
| 1280 | 0x500 | 0005 | |
| 1360 | 0x550 | 5005 | |
| 1366 | 0x556 | 5605 | |
| 1368 | 0x558 | 5805 | |
| 1440 | 0x5A0 | A005 | |
| 1536 | 0x600 | 0006 | |
| 1600 | 0x640 | 4006 | |
| 1680 | 0x690 | 9006 | |
| 1768 | 0x6E8 | E806 | |
| 1776 | 0x6F0 | F006 | |
| 1800 | 0x708 | 0807 | |
| 1920 | 0x780 | 8007 | |
| 2048 | 0x800 | 0008 | |
| 2160 | 0x870 | 7008 | |
| 2400 | 0x960 | 6009 | |
| 2560 | 0xA00 | 000A | |
| 2720 | 0xAA0 | A00A | |
| 2880 | 0xB40 | 400B | |
| 3072 | 0xC00 | 000C | |
| 3200 | 0xC80 | 800C | |
| 3360 | 0xD20 | 200D | |
| 3440 | 0xD70 | 700D | |
| 3840 | 0xF00 | 000F | |
| 4080 | 0xFF0 | F00F | |
| 4320 | 0x10E0 | E010 | |
| 4800 | 0x12C0 | C012 | |
| 5040 | 0x13B0 | B013 | |
| 5120 | 0x1400 | 0014 | |
| 5760 | 0x1680 | 8016 |
Sometimes the field of view (fov) for a game can be found in hexadecimal form in one of the game's files. The format you will most likely see is the IEEE 754 standard which is comprised of four hexadecimal pairs.
For example an FOV of 60.0 would be the following in hexadecimal.
42 70 00 00
This will almost always be formatted to be read from right to left in the game's files. So 42 70 00 00 becomes the following in the file.
00 00 70 42
You can use a IEEE 754 calculator to get your FOV value into hexadecimal format. Simply paste your FOV in the decimal field and click the Rounded or Not Rounded button (should not matter) and look at the hexadecimal result under the single precision fields.
Think of the hexadecimal value in this format.
ST UV WX YZ
You will be using it in this format.
YZ WX UV ST
Remember you can calculate the field of view by using the FOV Calc tool on this site along with any of several other methods for calculating the field of view.
When re-calculating fov based on aspect ratio, it can be done using trigonometric tangent functions to convert the angle to radians divided into half, then converted into a zoomable angle that can be divided or multiplied by the zoom factor and converted back into degrees.
For example, the current display ratio is 4:3 and the conditional aspect ratio is 16:9, the fov degrees of 45.0 would become 57.822402 from dividing the aspect ratio by the conditional aspect after converting the angle into a tangent angle:
Degrees:
Arctan(Tan(Fovy * PI / 360) / (4/3) * (16/9)) * 360 / PI
Degrees converted from radians:
Arctan(Tan(Fovyradians / 2) / (4/3) * (16/9)) * 360 / PI
Radians:
2 x Arctan(Tan(Fovyradians / 2) / (4/3) * (16/9))
Radians converted from Degrees:
2 x Arctan(Tan(Fovy * PI / 360) / (4/3) * (16/9))
(Above information provided by Tanuki)