> ## Documentation Index
> Fetch the complete documentation index at: https://lago-ftr-wallet-improvements.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Spending minimums

<Info>**Premium feature ✨**: only users with a premium license can define a charge spending minimum.
Please **[contact us](mailto:hello@getlago.com)** to get access to Lago Cloud and Lago Self-Hosted Premium.</Info>

Usage-based charges are always paid at the end of the billing period, based on the amount of consumption that occurred. However, you
could possibly need to define a spending minimum that a customer needs to commit to.

If your customer spends less than the committed amount, you will **charge a true-up fee equal to the difference between the commitment
and the actual usage**. Please note that this true-up fee is tied to the initial charge but will appear as a separate line item in an
invoice or in a credit note.

**Spending minimums and true-up fees are always prorated based on the number of days used in the subscription**. This ensures
fairness if your customer signs up at the end of the month, upgrades to a new plan, or terminates an ongoing subscription
before the end of the period.

In the example below, a customer is billed based on Monthly Tracked Users (MTU), with a standard pricing of \$0.010 per tracked users.
However, the customer is committed to a spending minimum of \$100. If the total consumption of MTUs for the period is \$50, a true-up fee
of \$50 will be charged.

To define a charge spending minimum:

<Tabs>
  <Tab title="Dashboard">
    1. Go to a **Plan**;
    2. Add a usage-based **charge**;
    3. Define a price model;
    4. Click the add a **spending minimum** button; and
    5. Define a spending minimum **amount**.
  </Tab>

  <Tab title="API">
    Use the `min_amount_cents` field on a charge:

    <CodeGroup>
      ```bash Spending minimum for a charge
      LAGO_URL="https://api.getlago.com"
      API_KEY="__YOUR_API_KEY__"

      curl --location --request POST "$LAGO_URL/api/v1/plans" \
      --header "Authorization: Bearer $API_KEY" \
      --header 'Content-Type: application/json' \
      --data-raw '{
        "plan": {
          "name": "Premium",
          "code": "premium",
          "interval": "monthly",
          "description": "Premium plan for SMB companies",
          "amount_cents": 50000,
          "amount_currency": "USD",
          "trial_period": 0.0,
          "pay_in_advance": true,
          "bill_charges_monthly": true,
          "charges": [
            {
              "billable_metric_id": "1111_2222_3333_4444",
              "charge_model": "percentage",
              "pay_in_advance": false,
              "invoiceable": true,
              "min_amount_cents": 100,
              "properties": {
                "rate": "0.5",
                "fixed_amount": "1",
                "free_units_per_events": 3,
                "free_units_per_total_aggregation": null
              }
            }
          ]
        }
      }'
      ```
    </CodeGroup>
  </Tab>
</Tabs>