Stock CommNet Range Calculator
Use this tool to estimate the maximum theoretical communication distance between two KSP antennas (or an antenna and a ground station).
Tip: You can type normal numbers (like 2000000000) or scientific notation (like 2e9).
How KSP antenna range works
In stock Kerbal Space Program (CommNet), connection distance between two communication endpoints is based on each side's antenna strength value. A direct vessel-to-vessel link, or vessel-to-relay link, is not simply the larger antenna range; instead, KSP uses a geometric mean style equation.
Dmax = √(R1 × M1 × R2 × M2)where:
R1andR2are antenna ranges (meters)M1andM2are optional multipliers (difficulty/ground station effects)Dmaxis the theoretical maximum link distance
What this calculator gives you
- Maximum theoretical range between two antennas
- Effective range values after multipliers
- Reachability check if you enter current distance
- Distance margin (how much range you have left, or how far out of range you are)
How to use it for mission planning
1) Enter antenna values from your craft design
In the VAB/SPH or tracking view, find the antenna part's nominal range and enter it in meters.
If needed, use scientific notation so the numbers are easier to read (for example, 5e6 for 5,000,000 m).
2) Apply modifiers if your save settings use them
Difficulty and facility upgrades can alter practical communication reach. If you're uncertain, leave multipliers at 1 and compare with in-game behavior.
3) Add current route distance
Enter estimated separation between endpoints (e.g., probe-to-relay or relay-to-Kerbin). The calculator will instantly show whether the link is theoretically possible.
Example scenarios
Example A: Equal relays
If both relays are 1e8 meters and modifiers are 1, then:
Dmax = √(1e8 × 1e8) = 1e8 meters.
Symmetrical antennas give a max distance equal to each antenna's own value.
Example B: Asymmetrical deep-space route
A small probe with 2e9 connecting to a powerful relay with 1e11 gives:
Dmax = √(2e20) ≈ 1.414e10 meters (about 14.14 Gm).
This is why a strong relay network dramatically helps weak probes.
Practical relay network tips
- Use at least three relays per planetary orbit for better continuous coverage.
- Place relays high enough to minimize line-of-sight occlusion by terrain or planetary bodies.
- Mix one high-power backbone relay with lighter local relays for efficiency.
- Build with margin: don't target exactly 100% of theoretical range.
- Remember that this formula checks distance only, not all in-game topology constraints.
Common mistakes to avoid
- Confusing kilometers and meters when entering values
- Assuming a weak probe can always talk directly to Kerbin
- Ignoring upgrades and difficulty modifiers in career mode
- Designing with zero margin near transfer window extremes
FAQ
Does this work for stock KSP only?
Yes—this calculator is designed around stock CommNet style range math. Mods that overhaul communications (such as RemoteTech-style systems) may use different rules.
Does it calculate exact signal quality?
No. It calculates maximum theoretical link distance and distance utilization. Signal quality can depend on additional in-game factors.
Can I use this for DSN planning?
Absolutely. Treat the Deep Space Network side as one endpoint with its effective range and multiplier, then compare against your probe or relay antenna.
If you're building a long-duration exploration career, this quick calculator can save a lot of trial-and-error and help you place relays with confidence.