# Determining gas requirements

Determining [gas requirements (gasreq)](https://docs.mangrove.exchange/dev/quick-links/glossary#gasreq) for your offer logic in a maker contract is important to avoid failures, save on provision, and make offers as attractable as possible. There is a lot that can be said and calculated about gas requirements - we will focus on the essential here, and give you pointers for your own assessments.

### What to test[​](https://old.docs.mangrove.exchange/developers/strat-lib/guides/howtoGasreq#what-to-test) <a href="#what-to-test" id="what-to-test"></a>

To determine the `gasreq`, you need to measure the **worst case gas usage** when [`makerExecute`](https://docs.mangrove.exchange/dev/quick-links/glossary#makerexecute) and [`makerPosthook`](https://docs.mangrove.exchange/dev/quick-links/glossary#makerposthook) are called. There could be exception cases which are very gas costly, where you simply want the offer to fail instead (and you could skip those).

As a strat builder, you should **verify your gas usage** in some specific scenarios, and **compare deltas to other scenarios** tested [here](https://github.com/mangrovedao/mangrove-core/blob/2ae172805fd8b309c30b2dc877dba66245abbb3e/test/core/gas/README.md#scenarios). You should then use the results to set a `gasreq` for your strat which covers the desired worst-case scenarios. The gas measurements are for the inner-most operation.

The gasreq should be taken into account when [provisioning](https://docs.mangrove.exchange/dev/protocol/technical-references/makers/offer-provisions).

### Exisiting strategies[​](https://old.docs.mangrove.exchange/developers/strat-lib/guides/howtoGasreq#exisiting-strategies) <a href="#exisiting-strategies" id="exisiting-strategies"></a>

#### MangroveOrder[​](https://old.docs.mangrove.exchange/developers/strat-lib/guides/howtoGasreq#mangroveorder) <a href="#mangroveorder" id="mangroveorder"></a>

Here, we will calculate the optimum `gasreq` to use [MangroveOrder](https://docs.mangrove.exchange/dev/strat-lib/technical-references/api-preferences/strats/src/strategies/mangroveorder), a Forwarder logic with a [simple router](https://docs.mangrove.exchange/dev/strat-lib/technical-references/liquidity-routing):

* MangroveOrder's most expensive case is `148451` (more details [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/MgvOrder.gasreq.t.sol#L18))

It's worth mentioning as well that there is a slightly more expensive path going through Mangrove core, which should be taken into account:

* `19675` is the comparable case for core (see [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/MgvOrder.gasreq.t.sol#L22))
* `22841` is the more expensive path, which would be if an offer existed in the same bin as the reposted offer (see [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/MgvOrder.gasreq.t.sol#L23))

The difference between the two is just above `3000`, hence we add that and round up to get an optimum `gasreq` of `82000` for MangroveOrder.

#### Kandel[​](https://old.docs.mangrove.exchange/developers/strat-lib/guides/howtoGasreq#kandel) <a href="#kandel" id="kandel"></a>

**Standard Kandel**[**​**](https://old.docs.mangrove.exchange/developers/strat-lib/guides/howtoGasreq#standard-kandel)

Here, we will calculate the optimum `gasreq` to use the [Kandel](https://docs.mangrove.exchange/dev/strat-lib/technical-references/api-preferences/strats/src/strategies/offer_maker/market_making/kandel) strategy:

* Kandel's most expensive case is `121413` (see [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/kandel/Kandel.gasreq.t.sol#L21))

Similarly to [MangroveOrder](https://docs.mangrove.exchange/dev/strat-lib/technical-references/api-preferences/strats/src/strategies/mangroveorder), there is a more expensive path going through Mangrove core to be taken into account:

* `44339` is the comparable case for core (see [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/kandel/Kandel.gasreq.t.sol#L23))
* `45090` is the more expensive path, if another offer existed on the dual offer's bin (see [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/kandel/Kandel.gasreq.t.sol#L24))
* The difference is below `1000`.

Similarly for the primary offer:

* `19675` is the comparable case for core (see [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/kandel/Kandel.gasreq.t.sol#L27))
* `22841` is the more expensive path, if an offer existed in the same bin as the reposted offer (see [here](https://github.com/mangrovedao/mangrove-strats/blob/a265abeb96a053e386d346c7c9e431878382749c/test/strategies/kandel/Kandel.gasreq.t.sol#L28))
* The difference is just above `3000`, so we add both (`4000`) and round it up to get `126000`.