# [RPG] formula to calculate level given experience

dnd-4eexperience-points

I have a spreadsheet that tracks the XP for our group and I've gotten tired of manually looking up how much xp is needed for the next level.

I'd much prefer if there was a formula I could put on the spreadsheet that would calculate the level given the XP? (Without using a lookup table)

"After 2nd level, the amount of experience you need to gain a level goes up by 250 points (i.e., you need +1,000 to reach level 2, +1,250 to reach level 3, etc.). After four levels of this, the 'additional' amount increases to 500. About the point you'd expect this to continue, it gets extremely erratic on levels 11 (+1,500) and 12 (+500), then reverts back to +1,000 at 13th and 14th. Levels 15-18 add +2,000 each, and 19-20 start at +4,000 -- this implies the amount added doubles every four levels.

Except that level 21 adds +8,000, and 22 adds +3,000. After that little bit of weirdness, it does +10,000 for four levels, and +25,000 for the last four."

Here's a rough chart of the results; the first column is from the RAW, the second removes the 'jagged' parts, and the third assumes a simple doubling every time. The numbers on the latter two look funny, but the progression itself is easier to predict.

`````` RAW    Smooth   Doubler
1          0         0         0
2      1,000     1,000     1,000
3      2,250     2,250     2,250
4      3,750     3,750     3,750
5      5,500     5,500     5,500
6      7,500     7,500     7,500
7     10,000    10,000    10,000
8     13,000    13,000    13,000
9     16,500    16,500    16,500
10     20,500    20,500    20,500
11     26,000    25,500    25,500 <- 500 XP difference
12     32,000    31,500    31,500
13     39,000    38,500    38,500
14     47,000    46,500    46,500
15     57,000    56,500    56,500
16     69,000    68,500    68,500
17     83,000    82,500    82,500
18     99,000    98,500    98,500
19    119,000   118,500   118,500
20    143,000   142,500   142,500
21    175,000   170,500   170,500 <- 4,500 XP difference
22    210,000   202,500   202,500 <- 7,500 XP difference
23    255,000   244,500   242,500 <- 10,500/12,500
24    310,000   296,500   290,500 <- 13,500/19,500
25    375,000   358,500   346,500 <- 16,500/28,500
26    450,000   430,500   410,500 <- 19,500/39,500
27    550,000   527,500   490,500 <- 22,500/59,500
28    675,000   649,500   586,500 <- 25,500/88,500
29    825,000   796,500   698,500 <- 28,500/126,500
30  1,000,000   968,500   826,500 <- 31,500/176,500
``````

There are no clean mathematical formulas to approximate this, according to the curve-fitting service ZunZun.com. While my prior equation did serve to ... output the rates of increase, a lookup table or your own XP chart should serve better.

Curiously, this does highlight some interesting questions about the relative time per level, suggesting that a custom XP chart may provide a more consistent levelling experience for your players.

Edit. Here's a quick and dirty reverse lookup that worked in excel 2008. `=VLOOKUP(A1,{0,1;1000,2;2250,3;3750,4;5500,5;6500,6;10000,7;13000,8;16500,9;20500,10;26000,11;32000,12;39000,13;47000,14;57000,15;69000,16;83000,17;99000,18;119000,19;143000,20;175000,21;210000,22;225000,23;310000,24;375000,25;450000,26;550000,27;675000,28;825000,29;1000000,30},2)`