diff --git a/scripts/convert_legacy_results.py b/scripts/convert_legacy_results.py
new file mode 100644
index 00000000..3ac9d205
--- /dev/null
+++ b/scripts/convert_legacy_results.py
@@ -0,0 +1,394 @@
+#!/usr/bin/env python3
+"""Convert legacy OFB HDF5 results to the current tally group schema.
+
+Legacy format (per group):
+- dataset named like the group, shape (realization, row, column)
+- coordinate datasets: realization, row, column
+- typical columns: [energy low, energy high, mean, std. dev.]
+
+New format (per group):
+- variables: mean, mc_std
+- dims: (surface, energy, nuclide, score)
+- attrs: filter_axes, nuclides, scores, observed_tally, optional spec_* fields
+"""
+
+from __future__ import annotations
+
+import argparse
+import importlib.util
+import json
+from pathlib import Path
+
+import h5py
+import numpy as np
+import xarray as xr
+import yaml
+
+
+def _normalize_filter_type(type_name: str) -> str:
+    name = str(type_name).strip().lower()
+    if name.endswith("filter"):
+        name = name[:-6]
+    return name
+
+
+def _filter_bins_match(spec_filter: dict, observed_axis: dict) -> bool:
+    expected = spec_filter.get("values")
+    observed = observed_axis.get("bins")
+    if expected is None or observed is None:
+        return True
+
+    ftype = _normalize_filter_type(spec_filter.get("type", ""))
+    if ftype == "energy":
+        try:
+            return np.allclose(np.asarray(expected, dtype=float), np.asarray(observed, dtype=float))
+        except Exception:
+            return False
+
+    try:
+        return list(expected) == list(observed)
+    except Exception:
+        return False
+
+
+def _validate_tally_consistency(spec_tally: dict, observed_tally: dict) -> tuple[bool, list[str]]:
+    issues: list[str] = []
+
+    observed_scores = [str(s) for s in observed_tally.get("scores", [])]
+    observed_nuclides = [str(n) for n in observed_tally.get("nuclides", [])]
+    observed_filters = list(observed_tally.get("filters", []))
+
+    spec_scores = [str(s) for s in spec_tally.get("scores", [])]
+    if spec_scores and spec_scores != observed_scores:
+        issues.append(f"scores mismatch: expected {spec_scores}, observed {observed_scores}")
+
+    spec_nuclides = [str(n) for n in spec_tally.get("nuclides", [])]
+    if spec_nuclides and spec_nuclides != observed_nuclides:
+        issues.append(f"nuclides mismatch: expected {spec_nuclides}, observed {observed_nuclides}")
+
+    expected_particle = spec_tally.get("particle")
+    if expected_particle is not None:
+        particle_filters = [a for a in observed_filters if _normalize_filter_type(a.get("name", "")) == "particle"]
+        if not particle_filters:
+            issues.append("missing ParticleFilter in observed tally")
+        else:
+            bins = particle_filters[0].get("bins", [])
+            observed_particle = str(bins[0]) if bins else None
+            if str(expected_particle) != str(observed_particle):
+                issues.append(
+                    f"particle mismatch: expected {expected_particle}, observed {observed_particle}"
+                )
+
+    spec_filters = spec_tally.get("filters", [])
+    observed_non_particle = [
+        a for a in observed_filters if _normalize_filter_type(a.get("name", "")) != "particle"
+    ]
+
+    expected_types = [_normalize_filter_type(f.get("type", "")) for f in spec_filters]
+    observed_types = [_normalize_filter_type(a.get("name", "")) for a in observed_non_particle]
+    if expected_types != observed_types:
+        issues.append(f"filter type/order mismatch: expected {expected_types}, observed {observed_types}")
+
+    return len(issues) == 0, issues
+
+
+def _load_spec_lookup(repo_root: Path, benchmark: str | None) -> dict[str, dict]:
+    if not benchmark:
+        return {}
+
+    spec_path = repo_root / "src" / "openmc_fusion_benchmarks" / "benchmarks" / benchmark / "specifications.yaml"
+    if not spec_path.exists():
+        raise FileNotFoundError(f"Could not find specifications file: {spec_path}")
+
+    with spec_path.open("r", encoding="utf-8") as f:
+        spec = yaml.safe_load(f)
+
+    lookup: dict[str, dict] = {}
+    for entry in spec.get("tallies", []):
+        if isinstance(entry, dict) and entry.get("name"):
+            lookup[str(entry["name"])] = entry
+    return lookup
+
+
+def _decode_columns(group: h5py.Group) -> list[str]:
+    cols_raw = group["column"][()]
+    cols: list[str] = []
+    for c in cols_raw:
+        if isinstance(c, bytes):
+            cols.append(c.decode("utf-8"))
+        else:
+            cols.append(str(c))
+    return cols
+
+
+def _col_index(columns: list[str], candidates: list[str]) -> int:
+    normalized = [c.strip().lower().replace("_", " ") for c in columns]
+    for cand in candidates:
+        c = cand.strip().lower().replace("_", " ")
+        for i, col in enumerate(normalized):
+            if c == col:
+                return i
+    for cand in candidates:
+        c = cand.strip().lower().replace("_", " ")
+        for i, col in enumerate(normalized):
+            if c in col:
+                return i
+    raise KeyError(f"Could not find column from candidates {candidates}. Found columns: {columns}")
+
+
+def _legacy_group_to_dataset(group_name: str, arr: np.ndarray, columns: list[str], tally_id: int, spec_tally: dict | None) -> xr.Dataset:
+    if arr.ndim != 3:
+        raise ValueError(f"Expected legacy data shape (realization, row, column), got {arr.shape}")
+    if arr.shape[0] < 1:
+        raise ValueError(f"Legacy dataset for '{group_name}' has no realization axis entries")
+
+    low_idx = _col_index(columns, ["energy low [ev]", "energy low", "energy_low [ev]", "energy_low"])
+    high_idx = _col_index(columns, ["energy high [ev]", "energy high", "energy_high [ev]", "energy_high"])
+    mean_idx = _col_index(columns, ["mean"])
+    std_idx = _col_index(columns, ["std. dev.", "std dev", "std_dev", "mc_std", "std"])
+
+    first = arr[0, :, :]
+    low = np.asarray(first[:, low_idx], dtype=float)
+    high = np.asarray(first[:, high_idx], dtype=float)
+    mean_all = np.asarray(arr[:, :, mean_idx], dtype=float)
+    mc_std_all = np.asarray(arr[:, :, std_idx], dtype=float)
+
+    if len(low) == 0:
+        energy_edges = np.asarray([], dtype=float)
+    else:
+        energy_edges = np.concatenate([low[:1], high])
+
+    particle = None
+    if isinstance(spec_tally, dict):
+        particle = spec_tally.get("particle")
+    if not particle:
+        low_name = group_name.lower()
+        if "neutron" in low_name:
+            particle = "neutron"
+        elif "photon" in low_name or "gamma" in low_name:
+            particle = "photon"
+
+    n_real = int(arr.shape[0])
+    n_rows = int(arr.shape[1])
+
+    # Build filter metadata in the same style as backend/openmc/tallies.py.
+    filter_axes: list[dict] = [
+        {
+            "name": "ParticleFilter",
+            "axis": "particle",
+            "num_bins": 1,
+            "bins": [particle] if particle is not None else [],
+        }
+    ]
+
+    spec_filters = list(spec_tally.get("filters", [])) if isinstance(spec_tally, dict) else []
+    used_dims: dict[str, int] = {}
+    non_particle_axes: list[dict] = []
+
+    for sf in spec_filters:
+        ftype = _normalize_filter_type(sf.get("type", ""))
+        class_name = f"{ftype.capitalize()}Filter" if ftype else "Filter"
+
+        base_dim = ftype or "filter"
+        dim_idx = used_dims.get(base_dim, 0)
+        used_dims[base_dim] = dim_idx + 1
+        axis_name = base_dim if dim_idx == 0 else f"{base_dim}_{dim_idx}"
+
+        if ftype == "energy":
+            bins = energy_edges.tolist()
+            num_bins = max(len(bins) - 1, 0)
+            axis_meta = {
+                "name": class_name,
+                "axis": axis_name,
+                "num_bins": int(num_bins),
+                "bins": bins,
+                "kind": "edges",
+                "units": sf.get("units", "eV"),
+            }
+        else:
+            bins = list(sf.get("values", []))
+            axis_meta = {
+                "name": class_name,
+                "axis": axis_name,
+                "num_bins": int(len(bins)),
+                "bins": bins,
+            }
+            if "units" in sf:
+                axis_meta["units"] = sf.get("units")
+
+        non_particle_axes.append(axis_meta)
+
+    # Fallback when specs are absent/incomplete: keep a single energy axis.
+    if not non_particle_axes:
+        non_particle_axes = [
+            {
+                "name": "EnergyFilter",
+                "axis": "energy",
+                "num_bins": int(n_rows),
+                "bins": energy_edges.tolist() if len(energy_edges) == n_rows + 1 else np.arange(n_rows + 1, dtype=float).tolist(),
+                "kind": "edges",
+                "units": "eV",
+            }
+        ]
+
+    # Legacy rows represent flattened non-particle filter bins. If the spec-driven
+    # product does not match, fall back to a single energy axis to preserve data.
+    non_particle_sizes = [int(a.get("num_bins", 0)) for a in non_particle_axes]
+    prod = int(np.prod(non_particle_sizes)) if non_particle_sizes else 0
+    if prod != n_rows:
+        non_particle_axes = [
+            {
+                "name": "EnergyFilter",
+                "axis": "energy",
+                "num_bins": int(n_rows),
+                "bins": energy_edges.tolist() if len(energy_edges) == n_rows + 1 else np.arange(n_rows + 1, dtype=float).tolist(),
+                "kind": "edges",
+                "units": "eV",
+            }
+        ]
+        non_particle_sizes = [n_rows]
+
+    filter_axes.extend(non_particle_axes)
+
+    # Legacy files typically carry a single score/nuclide aggregate per row.
+    if isinstance(spec_tally, dict) and len(spec_tally.get("scores", [])) == 1:
+        scores = [str(spec_tally["scores"][0])]
+    else:
+        scores = ["current"]
+
+    if isinstance(spec_tally, dict) and len(spec_tally.get("nuclides", [])) == 1:
+        nuclides = [str(spec_tally["nuclides"][0])]
+    else:
+        nuclides = ["total"]
+
+    dims = ("realization", "particle", *(a["axis"] for a in non_particle_axes), "nuclide", "score")
+
+    mean_nd = mean_all.reshape((n_real, 1, *non_particle_sizes, 1, 1))
+    std_nd = mc_std_all.reshape((n_real, 1, *non_particle_sizes, 1, 1))
+
+    coords = {
+        "realization": ("realization", np.arange(n_real, dtype=int)),
+        "particle": ("particle", np.asarray([0], dtype=int)),
+        "nuclide": ("nuclide", np.asarray(nuclides, dtype="U")),
+        "score": ("score", np.asarray(scores, dtype="U")),
+    }
+    for axis_meta in non_particle_axes:
+        axis = axis_meta["axis"]
+        coords[axis] = (axis, np.arange(int(axis_meta["num_bins"]), dtype=int))
+
+    ds = xr.Dataset(
+        {
+            "mean": xr.DataArray(mean_nd, dims=dims, coords=coords),
+            "mc_std": xr.DataArray(std_nd, dims=dims, coords=coords),
+        }
+    )
+
+    ds.attrs["filter_axes"] = json.dumps(filter_axes)
+    ds.attrs["scores"] = json.dumps(scores)
+    ds.attrs["nuclides"] = json.dumps(nuclides)
+
+    ds.attrs["group"] = group_name
+    ds.attrs["tally_name"] = group_name
+
+    ds["mean"].attrs["tally_id"] = int(tally_id)
+    ds["mean"].attrs["tally_name"] = group_name
+    ds["mean"].attrs["tally_group"] = group_name
+
+    ds["mc_std"].attrs["tally_id"] = int(tally_id)
+    ds["mc_std"].attrs["tally_name"] = group_name
+    ds["mc_std"].attrs["tally_group"] = group_name
+
+    observed_tally = {
+        "name": group_name,
+        "id": int(tally_id),
+        "filters": filter_axes,
+        "scores": scores,
+        "nuclides": nuclides,
+    }
+    ds.attrs["observed_tally"] = json.dumps(observed_tally)
+
+    if spec_tally is not None:
+        ds.attrs["spec_tally"] = json.dumps(spec_tally)
+        consistent, issues = _validate_tally_consistency(spec_tally, observed_tally)
+        ds.attrs["spec_consistent"] = int(bool(consistent))
+        ds.attrs["spec_consistency_issues"] = json.dumps(issues)
+
+    return ds
+
+
+def convert_file(input_path: Path, output_path: Path, benchmark: str | None, engine: str) -> Path:
+    repo_root = Path(__file__).resolve().parents[1]
+    spec_lookup = _load_spec_lookup(repo_root, benchmark)
+
+    if output_path.exists():
+        output_path.unlink()
+
+    with h5py.File(input_path, "r") as src:
+        for idx, group_name in enumerate(src.keys(), start=1):
+            group = src[group_name]
+            if group_name not in group:
+                raise KeyError(f"Legacy group '{group_name}' missing data dataset '{group_name}'")
+            if "column" not in group:
+                raise KeyError(f"Legacy group '{group_name}' missing 'column' dataset")
+
+            arr = np.asarray(group[group_name][()])
+            columns = _decode_columns(group)
+            spec_tally = spec_lookup.get(group_name)
+
+            ds = _legacy_group_to_dataset(
+                group_name=group_name,
+                arr=arr,
+                columns=columns,
+                tally_id=idx,
+                spec_tally=spec_tally,
+            )
+            mode = "w" if idx == 1 else "a"
+            ds.to_netcdf(output_path, mode=mode, group=group_name, engine=engine)
+
+    return output_path.resolve()
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description="Convert legacy OFB result HDF5 format to the current tally schema.")
+    parser.add_argument("input", type=Path, help="Legacy input .h5 file")
+    parser.add_argument(
+        "-o",
+        "--output",
+        type=Path,
+        default=None,
+        help="Output .h5 file (default: <input_stem>_converted.h5)",
+    )
+    parser.add_argument(
+        "--benchmark",
+        type=str,
+        default=None,
+        help="Optional benchmark name to attach spec_tally and spec_consistency metadata.",
+    )
+    parser.add_argument(
+        "--engine",
+        choices=["auto", "h5netcdf"],
+        default="auto",
+        help="NetCDF engine to use (default: auto, which resolves to h5netcdf).",
+    )
+    args = parser.parse_args()
+
+    input_path = args.input.resolve()
+    if not input_path.exists():
+        raise FileNotFoundError(f"Input file not found: {input_path}")
+
+    output_path = args.output.resolve() if args.output else input_path.with_name(f"{input_path.stem}_converted.h5")
+    engine = _select_engine() if args.engine == "auto" else args.engine
+    out = convert_file(input_path=input_path, output_path=output_path, benchmark=args.benchmark, engine=engine)
+    print(f"Converted: {input_path} -> {out}")
+
+
+def _select_engine() -> str:
+    if importlib.util.find_spec("h5netcdf") is not None:
+        return "h5netcdf"
+    raise RuntimeError(
+        "h5netcdf is required for this converter. Install it with: pip install h5netcdf"
+    )
+
+
+if __name__ == "__main__":
+    main()
\ No newline at end of file
diff --git a/results_database/convert_to_new_format.py b/scripts/convert_to_new_format.py
similarity index 100%
rename from results_database/convert_to_new_format.py
rename to scripts/convert_to_new_format.py
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