diff --git a/data.py b/data.py
new file mode 100755
index 0000000..63cb28c
--- /dev/null
+++ b/data.py
@@ -0,0 +1,156 @@
+# (product name, unit weight)
+
+# D'Addario stock via http://www.daddario.com/upload/tension_chart_13934.pdf
+# Circle K String stock http://circlekstrings.com/CKSIMAGES/UnitWeightChart130105.pdf
+
+# string names don't necessarily match up with their actual product names
+
+daddario_plain_steel = (
+    ('DAPL007' , .00001085),
+    ('DAPL008' , .00001418),
+    ('DAPL0085', .00001601),
+    ('DAPL009' , .00001794),
+    ('DAPL0095', .00001999),
+    ('DAPL010' , .00002215),
+    ('DAPL0105', .00002442),
+    ('DAPL011' , .00002680),
+    ('DAPL0115', .00002930),
+    ('DAPL012' , .00003190),
+    ('DAPL013' , .00003744),
+    ('DAPL0135', .00004037),
+    ('DAPL014' , .00004342),
+    ('DAPL015' , .00004984),
+    ('DAPL016' , .00005671),
+    ('DAPL017' , .00006402),
+    ('DAPL018' , .00007177),
+    ('DAPL019' , .00007997),
+    ('DAPL020' , .00008861),
+    ('DAPL022' , .00010722),
+    ('DAPL024' , .00012760),
+    ('DAPL027' , .00014975),
+)
+
+daddario_nickle_wound = ( # XL
+    ('DANW017' , .00005524),
+    ('DANW018' , .00006215),
+    ('DANW019' , .00006947),
+    ('DANW020' , .00007495),
+    ('DANW021' , .00008293),
+    ('DANW022' , .00009184),
+    ('DANW024' , .00010857),
+    ('DANW025*', .00011875), # from the EXL110BT, an approximation
+    ('DANW026' , .00012671),
+    ('DANW028' , .00014666),
+    ('DANW030' , .00017236),
+    ('DANW032' , .00019347),
+    ('DANW034' , .00021590),
+    ('DANW036' , .00023964),
+    ('DANW037*', .00024872), # from the EXL115BT, an approximation
+    ('DANW038' , .00026471),
+    ('DANW039' , .00027932),
+    ('DANW040*', .00029570), # from the EXL120BT, an approximation
+    ('DANW042' , .00032279),
+    ('DANW044' , .00035182),
+    ('DANW046' , .00038216),
+    ('DANW048' , .00041382),
+    ('DANW049' , .00043014),
+    ('DANW050*', .00044720), # from the EXL115BT, an approximation
+    ('DANW052' , .00048109),
+    ('DANW054' , .00053838),
+    ('DANW056' , .00057598),
+    ('DANW059' , .00064191),
+    ('DANW060' , .00066542),
+    ('DANW062' , .00070697),
+    ('DANW064' , .00074984),
+    ('DANW066' , .00079889),
+    ('DANW068' , .00084614),
+    ('DANW070' , .00089304),
+    ('DANW072' , .00094124),
+    ('DANW074' , .00098869),
+    ('DANW080' , .00115011),
+)
+
+kalium_plain = (
+    ('CKPL008 ',.0000142401458191),
+    ('CKPL0085',.00001607510288),
+    ('CKPL009', .0000180219146483),
+    ('CKPL0095',.00002008032129),
+    ('CKPL010', .0000222518914107),
+    ('CKPL0105',.00002453144932),
+    ('CKPL011', .0000269251480883),
+    ('CKPL0115',.00002942561205),
+    ('CKPL012', .0000320389593746),
+    ('CKPL0125',.00003476567932),
+    ('CKPL013', .0000376052948255),
+    ('CKPL0135',.00004055150041),
+    ('CKPL014', .000043607),
+    ('CKPL015', .000050050),
+    ('CKPL016', .000056961),
+    ('CKPL017', .000064300),
+    ('CKPL018', .000072088),
+    ('CKPL019', .000080360),
+    ('CKPL020', .000089031),
+    ('CKPL021', .000098155),
+    ('CKPL022', .000107666),
+    ('CKPL023', .000117702),
+)
+
+kalium_hybrid_wound = (
+    ('CKHW021', .000093873),
+    ('CKHW022', .000103500),
+    ('CKHW023', .000113985),
+    ('CKHW024', .000124963),
+    ('CKHW025', .000136054),
+    ('CKHW026', .000144691),
+    ('CKHW027', .000153146),
+    ('CKHW028', .000161203),
+    ('CKHW029', .000178551),
+    ('CKHW031', .000198902),
+    ('CKHW033', .000223217),
+    ('CKHW035', .000249034),
+    ('CKHW037', .000276237),
+    ('CKHW039', .000304788),
+    ('CKHW041', .000334965),
+    ('CKHW043', .000366357),
+    ('CKHW045', .000404956),
+    ('CKHW047', .000447408),
+    ('CKHW049', .000475438),
+    ('CKHW051', .000512645),
+    ('CKHW053', .000551898),
+    ('CKHW055', .000584407),
+    ('CKHW057', .000625704),
+    ('CKHW059', .000679149),
+    ('CKHW061', .000720293),
+    ('CKHW063', .000765973),
+    ('CKHW065', .000821116),
+    ('CKHW067', .000870707),
+    ('CKHW070', .000939851),
+    ('CKHW073', .001021518),
+    ('CKHW076', .001110192),
+    ('CKHW079', .001188974),
+    ('CKHW082', .001293598),
+    ('CKHW086', .001416131),
+    ('CKHW090', .001544107),
+    ('CKHW094', .001677765),
+    ('CKHW098', .001831487),
+    ('CKHW102', .001986524),
+    ('CKHW106', .002127413),
+    ('CKHW112', .002367064),
+    ('CKHW118', .002616406),
+    ('CKHW124', .002880915),
+    ('CKHW130', .003154996),
+    ('CKHW136', .003441822),
+    ('CKHW142', .003741715),
+    ('CKHW150', .004051506),
+    ('CKHW158', .004375389),
+    ('CKHW166', .005078724),
+    ('CKHW174', .005469937),
+    ('CKHW182', .006071822),
+    ('CKHW190', .006605072),
+    ('CKHW200', .007311717),
+    ('CKHW210', .008037439),
+    ('CKHW222', .009091287),
+    ('CKHW232', .009888443),
+    ('CKHW244', .010907182),
+    ('CKHW254', .011787319),
+)
diff --git a/notes.py b/notes.py
new file mode 100755
index 0000000..c9a4674
--- /dev/null
+++ b/notes.py
@@ -0,0 +1,50 @@
+#!/usr/bin/python
+
+A = 440
+notes = {
+    'C' :  0,
+    'D' :  2,
+    'E' :  4,
+    'F' :  5,
+    'G' :  7,
+    'A' :  9,
+    'B' :  11,
+}
+
+rel = (2**(1/12.))
+def note2freq(name):
+    sharp = name[1] == '#'
+    flat  = name[1] == 'b'
+    if sharp or flat:
+        note = name[0:1]
+        octave = int(name[2])
+    else:
+        note = name[0]
+        octave = int(name[1])
+    num = notes[note]
+    if sharp:
+        num += 1
+    if flat:
+        num -= 1
+    fullnum = num + 12*(octave - 5)
+    return A*rel**(fullnum + 3)
+
+if __name__ == '__main__':
+    test_fmt = '{:3} gave {: 9.2f} Hz\nexpected {: 9.2f} Hz'
+    def test(name, expected):
+        print(test_fmt.format(name, note2freq(name), expected))
+
+    test('C2' ,  65.41)
+    test('Ab4', 415.30)
+    test('A4' , 440.00)
+    test('B4' , 493.88)
+    test('B#4', 523.25)
+    test('Cb5', 493.88)
+    test('C5' , 523.25)
+    print()
+    test('E4' , 329.63)
+    test('B3' , 246.94)
+    test('G3' , 196.00)
+    test('D3' , 146.83)
+    test('A2' , 110.00)
+    test('E2' ,  82.41)
diff --git a/run.py b/run.py
new file mode 100755
index 0000000..a8f2725
--- /dev/null
+++ b/run.py
@@ -0,0 +1,81 @@
+#!/usr/bin/python
+
+from strings import print_ideal_stock
+
+in_mm = 25.4
+default_scale_length = 648/in_mm
+
+sets = """
+regular light
+E4  16  PD
+B3  16  PD
+G3  16  PD
+D3  16  WD
+A2  16  WD
+E2  16  WD
+
+jazz medium
+E4  24  PD
+B3  24  PD
+G3  24  WD
+D3  24  WD
+A2  24  WD
+E2  24  WD
+
+regular light (DADGAD)
+D4  16  PD
+A3  16  PD
+G3  16  PD
+D3  16  WD
+A2  16  WD
+D2  16  WD
+
+fanned-fret bass
+G2  35  WC  34.00
+D2  35  WC  34.75
+A1  35  WC  35.50
+E1  35  WC  36.25
+B0  35  WC  37.00
+
+regular light (Open G 7-string)
+D4  16  PD
+B3  16  PD
+G3  16  PD
+D3  16  WD
+B2  16  WD
+G2  16  WD
+D2  16  WD
+"""
+
+string_sets = {}
+sets = sets+'\n\n'
+title = None
+for line in sets.splitlines():
+    if not line:
+        title = None
+        continue
+    if not title:
+        title = line
+        string_sets[title] = []
+    else:
+        fields = line.split()
+        note, tension = fields[0:2]
+        tension = int(tension)
+
+        req = ''
+        if len(fields) > 2:
+            req = fields[2]
+
+        length = None
+        if len(fields) > 3:
+            length = float(fields[3])
+
+        string = (note, tension, req, length)
+        string_sets[title].append(string)
+
+print('for a scale length of {:>5.2f} inches'.format(default_scale_length))
+for name, strings in sorted(string_sets.items()):
+    print()
+    print('"{}"'.format(name))
+    print_ideal_stock(strings, default_scale_length)
+
diff --git a/run2.py b/run2.py
new file mode 100755
index 0000000..eb9dfb0
--- /dev/null
+++ b/run2.py
@@ -0,0 +1,84 @@
+#!/usr/bin/python
+
+from strings import print_tensions
+
+in_mm = 25.4
+default_scale_length = 648/in_mm
+
+sets = """
+E standard (super light balanced)
+E4  DAPL009
+B3  DAPL012
+G3  DAPL015
+D3  DANW022
+A2  DANW030
+E2  DANW040
+
+E standard (medium balanced)
+E4  DAPL011
+B3  DAPL015
+G3  DAPL019
+D3  DANW028
+A2  DANW037
+E2  DANW050
+
+C standard (medium balanced)
+C4  DAPL011
+G3  DAPL015
+D#3 DAPL019
+A#2 DANW028
+F2  DANW037
+C2  DANW050
+
+C standard (jazz medium)
+C4  DAPL013
+G3  DAPL017
+D#3 DANW026
+A#2 DANW036
+F2  DANW046
+C2  DANW056
+
+C standard (CKS-G6-14-59mb)
+C4  CKPL014
+G3  CKPL019
+D#3 CKHW025
+A#2 CKHW033
+F2  CKHW045
+C2  CKHW059
+
+B standard (CKS-G6-14-59mb)
+B3  CKPL014
+F#3 CKPL019
+D3  CKHW025
+A2  CKHW033
+E2  CKHW045
+B1  CKHW059
+
+D standard drop C (medium balanced)
+D4  DAPL011
+A3  DAPL015
+F3  DAPL019
+C3  DANW028
+G2  DANW037
+C2  DANW050
+"""
+
+string_sets = {}
+sets = sets+'\n\n'
+title = None
+for line in sets.splitlines():
+    if not line:
+        title = None
+        continue
+    if not title:
+        title = line
+        string_sets[title] = []
+    else:
+        note, string = line.split()
+        string_sets[title].append((note, string))
+
+print('for a scale length of {:>5.2f} inches'.format(default_scale_length))
+for name, strings in sorted(string_sets.items()):
+    print()
+    print('"{}"'.format(name))
+    print_tensions(strings, default_scale_length)
diff --git a/strings.py b/strings.py
new file mode 100755
index 0000000..b292869
--- /dev/null
+++ b/strings.py
@@ -0,0 +1,117 @@
+#!/usr/bin/python
+
+from data import *
+from notes import note2freq
+
+stock = []
+stock += daddario_plain_steel
+stock += daddario_nickle_wound
+stock += kalium_plain
+stock += kalium_hybrid_wound
+
+uw_const = 386.4
+def uw2tension(uw, freq, SL):
+    return (uw*(2*SL*freq)**2)/uw_const
+
+def tension2uw(t, freq, SL):
+    return (t*uw_const)/(2*SL*freq)**2
+
+outfmt = '\
+{:<8} at {:>6.2f} lb ({:>+4.2f})'
+finalfmt = '\
+average:   {:>7.2f} lb ({:>+5.2f})\n\
+total:     {:>7.2f} lb ({:>+5.2f})'
+tension_outfmt = '\
+{:<3} {:<8} at {:>6.2f} lb'
+tension_finalfmt = '\
+average:       {:>7.2f} lb\n\
+total:         {:>7.2f} lb'
+
+def print_ideal_stock(strings, scale_length=25.512):
+    SL = scale_length
+    total_tension = 0
+    total_desired_tension = 0
+    for note, tension, req, length in strings:
+        freq = note2freq(note)
+        if length:
+            SL = length
+        else:
+            SL = scale_length
+        uw = tension2uw(tension, freq, SL)
+
+        kind  = len(req) > 0 and req[0]
+        brand = len(req) > 1 and req[1]
+
+        closest = ('n/a', 0)
+        for name, stock_uw in stock:
+            if kind and kind == 'P' and name[2] != 'P':
+                continue
+            if kind and kind == 'W' and name[3] != 'W':
+                continue
+            if brand and brand[0] != name[0]:
+                continue
+            if abs(stock_uw - uw) < abs(closest[1] - uw):
+                closest = (name, stock_uw)
+
+        closest_tension = uw2tension(closest[1], freq, SL)
+        diff = closest_tension - tension
+        print(outfmt.format(closest[0], closest_tension, diff))
+
+        total_tension += closest_tension
+        total_desired_tension += tension
+
+    error = total_tension - total_desired_tension
+    average_tension = total_tension/len(strings)
+    average_error = error/len(strings)
+    print(finalfmt.format(average_tension, average_error, total_tension, error))
+
+def print_tensions(strings, scale_length=25.512):
+    SL = scale_length
+    total_tension = 0
+    for note, name in strings:
+        freq = note2freq(note)
+        uw = 0
+        for stock_name, stock_uw in stock:
+            if name == stock_name or name + '*' == stock_name:
+                uw = stock_uw
+                break
+        if uw:
+            tension = uw2tension(uw, freq, SL)
+        else:
+            tension = 0
+        print(tension_outfmt.format(note, name, tension))
+        total_tension += tension
+
+    print(tension_finalfmt.format(total_tension/len(strings), total_tension))
+
+if __name__ == '__main__':
+    # DAd's data is all screwy so we use change scale lengths for a best-fit
+    SL = 25.4825
+    D3 = note2freq('D3')
+    A2 = note2freq('A2')
+    E2 = note2freq('E2')
+
+    test_fmt = '{:8} {:10.8f} == {:10}'
+    def test(name, unit, tension, note):
+        print(test_fmt.format(name, tension2uw(tension, note, SL), unit))
+
+    test('NW024' , '0.00010857', 15.73, D3)
+    test('NW025*', '?'         , 17.21, D3)
+    test('NW026' , '0.00012671', 18.38, D3)
+    print()
+
+    test('NW036' , '0.00023964', 19.04, A2)
+    test('NW037*', '?         ', 20.23, A2)
+    test('NW038' , '0.00026471', 20.96, A2)
+    print()
+
+    SL = 25.18
+    test('NW039' , '0.00027932', 12.46, E2)
+    test('NW040*', '?         ', 13.18, E2)
+    test('NW042' , '0.00032279', 14.37, E2)
+    print()
+
+    SL = 25.02
+    test('NW049' , '0.00043014', 18.97, E2)
+    test('NW050*', '?         ', 19.68, E2)
+    test('NW052' , '0.00048109', 21.15, E2)