Below about 40 metres, the right trimix keeps your oxygen safe and your head clear. This best-mix calculator suggests an oxygen and helium blend for a target depth and equivalent narcotic depth (END).
Trimix best-mix calculator
Best mix: O₂ set by your PO₂ limit at depth, helium added so the equivalent narcotic depth stays within your END target. Default END counts nitrogen only; tick the box to count oxygen as narcotic too (a more conservative model some agencies use).
Important caveats
Use the Count O₂ as narcotic toggle to switch between the two common models: nitrogen-only (the default) and the more conservative oxygen-plus-nitrogen approach some agencies teach. The result changes noticeably, so always match the model to your own agency standards. Always plan trimix with proper software, agency standards and the training to back it up — this calculator is for learning and rough planning only.
Train in Cyprus
Dive mixed gas the right way
Trimix is a skill, not just a blend. Learn to plan and dive it safely with a structured course in Cyprus.
Instructor Insight
Calculators do not make a diver safe. They make the conversation visible. In training we always ask students to explain the number, the reserve and the decision behind it.
— Yurii Prokhvatylo
Instructor Insight
A checklist only works when the diver respects it under time pressure. We teach students to slow down before the dive, because most preventable problems start while everyone is rushing.
— Yurii Prokhvatylo
From the Training
One question students ask almost every technical course is whether planning gets faster. It does, but only after the diver stops skipping steps and starts recognising the pattern.
Frequently Asked Questions
Who is Trimix Calculator for?
This section is for deep divers estimating oxygen, helium and narcosis before a mixed-gas dive. It helps you decide whether trimix gas calculation fits your current certification, experience and goals. The aim is practical: understand the next step, prepare better questions and avoid choosing a dive or course only because the name sounds exciting.
What should I prepare before focusing on trimix gas calculation?
Before focusing on trimix gas calculation, be honest about recent dives, comfort in the water, buoyancy, gas awareness and equipment familiarity. Bring certification details and any limits you already know. That makes the conversation more useful than a generic recommendation and helps us suggest a realistic next step.
How does trimix gas calculation apply to diving in Cyprus?
Trimix gas calculation matters in Cyprus because warm water, good visibility and access to serious dive sites let training move from controlled practice to meaningful dives. The environment is comfortable, but the standards do not change. We still plan the dive, brief the team and build skills progressively.
Can trimix gas calculation support END targets, PO2 choices and depth planning?
Yes, when it matches your level. Trimix gas calculation can connect naturally with END targets, PO2 choices and depth planning, but it should not be rushed. We usually look at your recent experience first, then choose a route that keeps the training useful rather than simply adding a bigger objective.
What mistake does Trimix Calculator help divers avoid?
The common mistake is treating trimix gas calculation as a label instead of a set of habits. Divers often want the destination, certificate or tool before the underlying skill is stable. Good preparation keeps the plan simple, exposes weak points early and makes the real dive calmer.
When should I ask GoToDive about trimix gas calculation?
Contact GoToDive when you want to review a trimix idea. Send your certification level, recent dive history, dates in Cyprus and the outcome you want. A short, honest message helps us tell you whether to train first, dive first or build a staged plan.
Original GoToDive Photos

Small-part equipment detail
Teaching point: resources should help divers inspect real equipment, not skim generic advice.

Line and ring reference
Teaching point: this card supports checklists, rigging decisions and equipment awareness.

Light beam reference
Teaching point: the card connects resources to real-world visibility and signalling problems.

Zenobia layout model
Teaching point: visual references turn planning sheets into practical route decisions.

Equipment check in low light
Teaching point: the card is about using resources before stress makes thinking harder.
Continue Learning
Gas Calculator
Estimate bottom gas and reserve before the dive.
Dive Planning Sheets
Turn a dive idea into a shared team plan.
Zenobia Maps
Use wreck orientation as part of the planning process.