Use Advanced Formulas with Metered Fields
Last updated on Aug 28, 2026
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Combine multiple Meters into a single calculated value on a Metered Field, so customers see one meaningful number instead of several raw meter readings they'd have to add up themselves. Use a formula to simplify what appears on the invoice, apply thresholds, or calculate a derived metric like a ratio or net usage that no single Meter provides on its own.
By default, a Metered Field displays the raw aggregated value for each Meter you select. For example, instead of showing reads and writes as two separate rows, you could display a single Total I/O Metered Field driven by the formula [reads] + [writes].
Important: Advanced Formulas in Metered Fields require the
meter_formulafeature to be enabled on your site, in addition to Metered Fields. Contact Maxio Support to request access.
Enable a formula on a Metered Field
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When creating or editing a Metered Field, click Switch Formula.
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Click Select Meters to choose the member Meters to include in your formula. All Meters must belong to the same Stream.
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Enter a formula expression using
[meter-handle]bracket notation, for example[reads] + [writes]orMAX([revenue] - [cost], 0). -
Click Validate to confirm the formula syntax and Meter references before saving.
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Click Save.
Supported formula syntax
| Element | Syntax | Example |
|---|---|---|
| Meter reference | [meter-handle] | [api-calls], [storage-gb] |
| Addition | + | [reads] + [writes] |
| Subtraction | - | [revenue] - [cost] |
| Multiplication | * | [calls] * 0.01 |
| Division | / | [total] / [count] |
| Less than | < | [usage] < 1000 |
| Greater than | > | [usage] > 1000 |
| Absolute value | ABS(expr) | ABS([inbound] - [outbound]) |
| Minimum | MIN(a, b) | MIN([usage], 1000) |
| Maximum | MAX(a, b) | MAX([usage] - [included], 0) |
| Round | ROUND(expr, places) | ROUND([revenue] / [count], 2) |
| Conditional | IF(condition, value_if_true, value_if_false) | IF([usage] < 5000, 0, [usage]) |
Related information
To understand Metered Fields before configuring a formula, see Understand Metered Fields for Invoices.
To create and activate a Metered Field, see Create Metered Fields for Invoices.
For formula syntax used directly on a Meter (not within a Metered Field), see Use Advanced Formulas Between Meters.
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