Empty House Probability: How Common Is an Empty 7th House?
Venusward Research · Published September 13, 2026
An empty house means no planet in your chart landed inside it, purely a matter of geometry, not an omission and not a warning sign. Venusward calculated 20,000 simulated birth charts under Placidus and Whole Sign houses, using ten commonly counted planets, then measured how often the 7th house came back empty.
Key Numbers
| Metric | Value |
|---|---|
| P(7th house empty) — 10 planets, Placidus | 49.02% (±0.69%) |
| P(7th house empty) — 10 planets, Whole Sign | 49.10% (±0.69%) |
| P(7th house empty) — 12 planets, Placidus | 41.38% (±0.68%) |
| P(7th house empty) — 12 planets, Whole Sign | 40.81% (±0.68%) |
| Average empty houses per chart — Placidus | 5.723 ± 0.015 |
| Average empty houses per chart — Whole Sign | 5.672 ± 0.015 |
The ten planets counted here are the Sun through Pluto; the 12-planet count adds Chiron and the North Node. Numbers are from the "us" sample group (ten equally weighted U.S. cities) — see House System Disagreement for how often Placidus and Whole Sign reach a different verdict on the same chart.
By 7th House Cusp Sign
P(7th house empty), Placidus houses, 10 planets, same 20,000-chart run, broken out by the sign on the 7th house cusp:
| 7th house sign | n | P(empty 7th house) |
|---|---|---|
| Aries | 2,119 | 62.39% |
| Taurus | 1,987 | 56.47% |
| Gemini | 1,948 | 45.07% |
| Cancer | 1,567 | 35.61% |
| Leo | 1,228 | 25.81% |
| Virgo | 1,124 | 23.31% |
| Libra | 1,068 | 24.91% |
| Scorpio | 1,254 | 32.46% |
| Sagittarius | 1,645 | 53.98% |
| Capricorn | 1,952 | 62.30% |
| Aquarius | 2,037 | 60.43% |
| Pisces | 2,071 | 64.61% |
Method
20,000 simulated birth charts, birth dates spread uniformly from 1940 through 2005, placed across ten U.S. cities (the "us" sample group) with equal weight per city. Each chart is calculated twice: once under Placidus houses (the same production degradation function the free calculator uses, `calcHousesWithDegrade()`) and once under Whole Sign houses (`sweph.houses_ex(..., "W")`). Planet positions use the Swiss Ephemeris library in its file-free Moshier mode (`SEFLG_MOSEPH`) — the same mode the production calculator uses, measured against real ephemeris files at a maximum difference of 0.000260°, well inside the 0.01° tolerance this simulation cares about.
Script: scripts/research/empty-7th-house-sim.mjs. Reproduce with npx tsx scripts/research/empty-7th-house-sim.mjs 20000 1 write. Full source data (per-sign sample sizes and confidence intervals): docs/semrush-exports/astro/kw-mining-2026-08-27/H-empty-7th-house-sim.csv.
Limits
The by-sign table samples ten specific U.S. cities, not a continuous population distribution, and covers birth years 1940–2005 only. A second run with a different random seed moved one cell (12-planet Placidus, "us" group: 41.38% on the first seed, 40.30% on the second, a 1.08-point gap) past the ±1 percentage point tolerance this simulation targets — a normal sampling fluctuation at this sample size (about 2.2 standard errors, expected to happen occasionally across eight comparisons), not a methodology defect, and it doesn't change which of the two planet-count conditions has the lower empty rate. None of this describes marriage timing, an individual chart, or an outcome — only how often a purely geometric condition occurs across a simulated sample.
How to Cite
Venusward. "Empty House Probability in Birth Charts" (2026). https://venusward.com/research/empty-houses