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Constants and the formula expression editor

Updated 2026-06-22

Alongside the spreadsheet, Numio has a higher-level formula editor for defining named constants and building formula expressions out of your inputs, constants, and other formulas. This article covers how that editor works.

The three kinds of data

The editor organizes everything into three groups, each with its own color and reference letter:

| Group | Reference | What it is | |---|---|---| | User Inputs | C… | Values your end-user submits through input blocks | | Constants | F… | Static values that never change — sales tax, a fixed fee, a conversion rate | | Formula | K… | Expressions that combine inputs, constants, and other formulas into a result |

Each row gets a short reference token (like C1, F2, K3) that you use to refer to it inside an expression.

Adding a constant

  1. In the Constants group, click the + to add a row.
  2. Give it a title (for example, "Sales Tax").
  3. Enter its value.

Constants are for numbers that stay fixed across every reader — the kind of thing you'd otherwise hardcode into a formula. Pulling them out as named constants keeps your formulas readable.

Building a formula expression

  1. In the Formula group, click the + to add a formula, or select an existing one.
  2. Give the formula a title.
  3. Click into the expression area (it starts with an =) and type your expression.

You reference other data by its token. For example, if C1 is "Quantity", C2 is "Unit price", and F1 is "Sales tax", a total formula might read:

= C1 * C2 * (1 + F1)

References are uppercased automatically as you type, so you can type c1 and it becomes C1.

Visual vs. string mode

The formula area has two faces:

  • Formatted (visual) view — when you're not editing, tokens are shown with their friendly titles and colors, so the formula reads in plain language.
  • Editing (string) view — click into the area and it switches to a plain-text expression you type directly, in a monospace font.

Click out and it returns to the formatted view.

Conditional logic

You can write conditional expressions using IF, AND, OR, and NOT. The editor recognizes these and formats them in the visual view. A conditional looks like:

= IF(C1 > 100, C1 * 0.9, C1)

which returns a 10% discount when the quantity exceeds 100, and the plain value otherwise.

Saving and verifying

When the expression is ready, click Save. Numio validates the formula before storing it:

  • If it's valid, the formula is saved and marked verified.
  • If it can't be parsed, the input turns red and the formula isn't marked verified.

See Formula verification and errors for what the verified state means and how invalid formulas behave.

Where to go next