TA to Distance Calculator
Convert 5G NR Timing Advance values to UE-gNB distance. Supports all numerologies.
Timing Advance (TA) is how 5G NR and LTE keep UEs from different cell ranges arriving at the gNB synchronised on the air interface. The gNB measures the propagation round-trip delay and commands the UE to transmit earlier by N_TA basic time units so its uplink slots line up with everyone else's. Because TA is expressed in the basic time unit Tc (≈ 0.509 ns at μ = 0), and because the TA step scales with numerology (μ), a single TA value corresponds to different UE-to-gNB distances depending on the subcarrier spacing: ~78 m per unit at 15 kHz, ~39 m at 30 kHz, ~19.5 m at 60 kHz, and ~9.75 m at 120 kHz. This tool does the conversion in both directions — give it a TA and numerology and you get distance, or give it a distance and you get the TA value the gNB would send.
TA → Distance
Enter a Timing Advance value and numerology to get UE-to-gNB distance.
A TA of 100 at 30 kHz SCS corresponds to a UE distance of 61 m (0.06 km) from the gNB.
Distance → TA
Reverse direction: enter a UE distance to see the required TA value.
How It Works
The formulas implemented here:
Tc = 1 / (Δf_max × N_f) = 1 / (480 kHz × 4096) ≈ 0.509 ns t_round_trip = TA × 16 × 2^(-μ) × Tc seconds distance = t_round_trip × c / 2 metres
- μ = 0 (15 kHz SCS) → 1 TA unit ≈ 520.8 ns round-trip → 78 m one-way
- μ = 1 (30 kHz SCS) → ≈ 39 m per TA unit
- μ = 2 (60 kHz SCS) → ≈ 19.5 m per TA unit
- μ = 3 (120 kHz SCS) → ≈ 9.75 m per TA unit
The MAC CE that carries the TA command is 6 bits wide in the RAR (values 0–63, coarse initial TA), and 6 bits in the TA MAC CE (−31..+32 adjustments) during connected mode. The ambiguity range of a single TA command therefore scales inversely with μ: high-band 120 kHz SCS sessions re-TA much more frequently than low-band 15 kHz sessions.
3GPP References
- • TS 38.213 §4.2 — Timing advance
- • TS 38.211 §4.1 — Basic time unit Tc = 1/(Δf_max × N_f)
- • TS 38.321 §5.2 — MAC Timing Advance Command MAC CE
- • TS 38.133 — Requirements for support of radio resource management
Master this in our 5G/6G Academy courses
Go beyond the calculator — learn the 3GPP specs, real-world planning trade-offs, and hands-on labs from TELCOMA Global engineers.
Calculator gave you the answer? Learn the theory in 7 days, free.
$19.99/mo (global) · ₹999/mo (India). Full Pro access — 150+ hands-on exercises, 20+ troubleshooting Scenarios, 17 certifications, TelcoMentor AI coach. No credit card.
- No credit card
- Cancel anytime
- Full Pro access
- TELCOMA since 2009