Deterministic values versus live random rolls

Mechanic reference

Evidence and reliability

6 minute read

A reliability reference for comparing calculations without calling a simulated choice an exact future roll.

By RO Codex Team Updated August 7, 2026 Foundational mechanic · Reviewed August 7, 2026

How this damage is calculated

Calculation order

Known live range or branch → recorded deterministic simulation choice → comparable ledger event

Follow this order with your own build, but use the grouping and special branches shown by your skill family. The numerical example below demonstrates the mechanic rather than claiming one universal formula for every skill.

Build calculator

Enter the values from your character, skill, and target. Results update as you type, stay in your browser, and are never saved.

Instant result

Your character stats

Enter the totals from the build you use with the selected hero and attack. Action-specific, target-qualified, and Final Damage modifiers remain separate stages.

Build A base event

Build B base event

Live minimum roll

Comparison roll

Live maximum roll

Your calculated result

The deterministic comparison shows a 10% gain, while live outcomes can overlap from 49,500 to 55,000.

This calculator follows the ordering described on this page. Skill-specific rewrites and unsupported build lanes still require their own verified family support.

Example calculation: deterministic center versus live range

Worked example

A live mechanic varies from 90% to 110%. Build A has 50,000 base event damage, while Build B has 55,000 after a 10% upgrade.

Use your own values

Replace the sample inputs with your character stats, selected skill level, active modifiers, and actual target. The values below are not a recommended build, damage target, or expected result for your character.

Build A base event: 50,000
Build B base event: 55,000
Live minimum roll: 90% (×0.90)
Deterministic comparison value: 100% (×1.00)
Live maximum roll: 110% (×1.10)

1
Build A minimum 50,000 × 0.90
45,000
2
Build A deterministic center 50,000 × 1.00
50,000
3
Build A maximum 50,000 × 1.10
55,000
4
Build B minimum 55,000 × 0.90
49,500
5
Build B deterministic center 55,000 × 1.00
55,000
6
Build B maximum 55,000 × 1.10
60,500
7
Center-to-center gain 55,000 − 50,000
5,000 (+10%)

Example result

The deterministic comparison shows a 10% gain, while live outcomes can overlap from 49,500 to 55,000.

Use the live range published for your mechanic. A deterministic center is useful for comparing builds, but it does not predict the next server roll.

Use repeatability for comparison

Battle Lab chooses deterministic values when a live mechanic has a known range or branch. The selected value is recorded with the event so the same build, skill, target, and state can be compared without random noise.

A deterministic center or forced critical state is a simulation choice, not a claim about the next live-server roll. The player-facing explanation must show the known range or condition when available.

Keep evidence states honest

Proven client inputs and deterministic values derived from them can support a Verified result. An undocumented approximation, incomplete condition, or unresolved required branch downgrades the result to Estimated or Unavailable according to the trust contract.

Record the selected deterministic value.
Show the live range when known.
Do not hide deferred or unresolved material steps.

Repeat the same event state

When testing one upgrade, retain the same deterministic branch and target state. Once the better build is identified, use live observations as corroboration rather than replacing missing formula proof with one lucky or unlucky hit.

Apply this to your build

Compare two builds with the same recorded critical state and deterministic value. Then review the known live range to judge how much ordinary battle variance can change the outcome.

Evidence and freshness

RO Codex publishes Verified family articles only while the accepted handler and its required evidence remain current. Read the data quality standards for the site-wide accuracy contract.

RO Codex formula trust contract: Defines Verified, Estimated, and Unavailable behavior and requires family-specific fail-closed calculation.
Player-facing calculation ledgers: Ordered Battle Lab steps keep attack, defense, modifiers, encounters, and caps readable without exposing internal references.