Current usage returns zero for subscriptions with fixed charges

Last updated: June 30, 2026

The current_usage endpoint only aggregates usage-based (metered) charges. It does not include fixed charges or subscription fees in its totals. A subscription that has only a fixed charge, or whose charges are all paid in advance, will return $0 from current_usage. This is by design.

How it works

Lago's current_usage endpoint is scoped to consumption-driven charges (those tied to event ingestion and aggregation). Fixed charges are excluded because they are not usage-based.

How to resolve the issue

If you need a complete picture of what a subscription is accruing mid-period including fixed charges, subscription fees, and usage-based charges, use the invoices/preview endpoint instead. It returns:

  • The base subscription fee for the period

  • Usage-based charges based on events ingested so far

  • Fixed charges prorated to today

Use current_usage when you need a usage-only readout for metering or display purposes. Use invoices/preview when you need an estimate of what the customer will owe.

A note on fixed charge units in invoices/preview

Fixed charges are included in the invoices/preview response, but the endpoint does not accept overrides for fixed charge units in the payload. How the units are resolved depends on what you preview against:

  • If you pass subscriptions[external_ids] for an existing subscription, the preview uses that subscription's fixed charges, including any unit overrides set in the plan override.

  • If you preview against a plan (no subscription yet), it uses the plan's fixed charge units as-is.

  • There is currently no way to preview an invoice with custom/ad-hoc fixed charge units supplied inline in the payload. This is a known limitation of the feature as shipped.

If you find that fixed charges are missing from a preview response, confirm you are previewing against a subscription or plan that actually carries the fixed charge, as the units are pulled from there rather than from the request body.

This article reflects guidance drawn from customer case resolutions. It is not officially supported documentation and may not apply to all situations.