> For the complete documentation index, see [llms.txt](https://orbcity.gitbook.io/orbcity/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://orbcity.gitbook.io/orbcity/building/upgrading-system/level-up/cost.md).

# Cost

$$
Level~~up~~Cost=\[Lay\_{n}\* x\_l] +\[Orb\_{n}\*y\_l^2]
$$

$$
Lay\_{n}=Lay~~Mining~~per\~Day\[Lev.\alpha\_{+1}]
$$

$$
Orb\_{n}=Lay~~Mining~~per\~Day\[Lev.\alpha\_{+1}]\*{\sqrt {Lay\_{p}}\over \ \sqrt {Orb\_{p}}}
$$

$$
Lay\_{p}=Lay~~Price
\Orb\_{p}=Orb~~Price
$$

All costs for buildings are determined by the formula above. The cost is based on the amount of $Lay 007 mined. Because it is based on the amount of Lay mined, the Lay value is a fixed cost based on the tier and level of the building, but $Orb is a variable cost. The reason for the variable cost of $Orb is that when the price of $Orb is high, it is unlikely that further construction or upgrades will be triggered.

#### Level Up Cost

$$
x\_l=30
$$

$$
y\_l=25
$$

####

Coefficient of x and y for each tier & level

| Lev   | common | rare | epic | unique | legendary |
| ----- | ------ | ---- | ---- | ------ | --------- |
| 1 Lev | 1.00   | 1.12 | 1.24 | 1.36   | 1.48      |
| 2 Lev | 1.04   | 1.16 | 1.28 | 1.40   | 1.52      |
| 3 Lev | 1.08   | 1.20 | 1.32 | 1.44   | 1.56      |

The table above shows the coefficients by Tier & Level for the values of x, y. In other words, the values of x, y increase as the level and tier increase.

#### $LAY Cost

| Lev      | common | rare   | epic    | unique   | legendary |
| -------- | ------ | ------ | ------- | -------- | --------- |
| 1->2 Lev | 1.5000 | 5.0400 | 20.9250 | 120.4865 | 1081.7305 |
| 2->3 Lev | 1.8720 | 6.2640 | 25.9200 | 148.8396 | 1333.1570 |

#### $Orb Cost = Dynamic Cost

{% hint style="info" %}
The value of **x\_l and y\_l** may be adjusted by governance.
{% endhint %}

{% hint style="info" %}
**Note: Please note that all figures are subject to change by governance.**
{% endhint %}

{% hint style="info" %}
**Note: The prices of $ORB and $LAY are based on a 24-hour moving average.**
{% endhint %}

{% hint style="danger" %} <mark style="color:red;">**Note: Keep in mind that all tokens and NFTs spent on the upgrade are irrevocable and non-refundable.**</mark>
{% endhint %}