iStrelok is a ballistic trajectory calculator.
Small, handy and accurate. Field-proven accuracy since 2001.

Supports imperial units (yards, feet, inches, etc).
You can see holdovers on your reticle and scale holdovers to any magnification (if reticle is located in second focal plane).
Supported reticles:

MilDot (USMC),
MilDot (US Army),
***************BSA
Contender (BSA),
Contender Mil-Dot (BSA),
**************Burris
Ballistic Mildot,
XTR Ballistic Mildot,
Ballistic Plex,
Ballistic CQ 5.56,
Ballistic Plex E1 (3-9x, 4.5-14x),
G2B Mil-Dot
Bushnell
DOA 600,
G2DMR,
DOA 250,
BTR-1,
CF 500,
BTR-2,
BTR-Mil
****************Delta
HFT,
MCZ,
MCZ 2,
****************Hawke
1/2 Mil Dot 10x,
1/2 Mil Dot 20x,
SR12,
SR6,
MAP6,
MAP6a,
MAP8,
SR Pro,
L4 Dot
************Horus Vision
H-25,
H-37,
H-70,
H-58,
H-425,
H-59,
H-50,
H-27
**************Falcon
Enhanced Mildot,
ML16,
Brabant-20,
MOA
*************Kahles
4D,
SM1,
SI1,
Mil 4,
Mil 1,
4D-Dot (3,5-10x),
G4-B (1-6x),
Mil 6
********************Leica
Ballistic 2.5-10x42,
Ballistic 3.5-14x42,
Ballstic 1.5x-10x42 (Magnus),
Ballstic 2.4x-16x56 (Magnus),
*****************Leupold
SPR,
LR Duplex ,
LRV Duplex ,
Varmint Hunter's,
Boone and Crockett,
TMR,
Firedot,
SA.B.R.,
Firedot SPR,
CM-RW, 5.56/.223,
CM-RW, 7.62/.308,
Pig Plex,
Wide Duplex (FX-3 6x42),
Fine Duplex (VX-3 6.5-20),
Fine Duplex (VX-2 6-18),
Fine Duplex (VX-3 8.5-25),
Illuminated Duplex,
Duplex (VX-3 3.5-10, 4.5-14),
FireDot SPR,
Duplex (VX-6 1-6х24),
Duplex (VX-3 2.5-8x),
Duplex (VX-1 3-9x),
Fine Duplex (VX-2 4-12x),
********************March
MTR-1,
MTR-2,
MTR-3,
MTR-4,
FML-1 (3x-24x42),
FML-1 (5x-40x56),
FMA-1,
FMA-2,
MML
***************Meopta
K-5.56,
4C (R1r 3-12x56),
BDC,
McWhorter HV,
McWhorter MV,
4A,
Z-Plex II (6-18x50)
**************MTC Optics
SCB,
AMD,
SCB 2
**************Nightforce
NP-R2,
NP-R1,
MLR,
NP-1RR,
NP-2DD,
Velocity 600,
Velocity 1000,
MLR 2,
MOAR,
MD2.0,
MIL-R (SFP),
MIL-R (FFP),
DDR
****************Nikon
BDC Standart,
BDC Predator,
BDC 600,
BDC 250,
BDC 800
***********Nikko Stirling
LRX,
NATO,
FT,
FT (SMOA),
Duplex, Nighteater,
*************Premier Reticles
Gen 2 MilDot,
Gen 2 XR,
************Redfield
Accu-Range,
Accu-Ranger Varmint,
Accu-Ranger Hunter,
Accu-Ranger Subot ML,
Accu-Ranger Crossbow,
TAC-MOA
***************Schmidt&Bender
P4,
MSR,
A8Varmint,
FD7
************Shepherd
P1,
P2,
P3,
P1A
***********Sightron
MOA 2,
MOA 3,
HHR,
Modified Mil-Dot
**********Swarovski
BR,
4A-300,
TDS-4,
TDS,
BRT, BRX&BRH
**************Trijicon
Chevron, TA31 ACOG,
TA01NSN,
TA01
**************Vortex
EBR-1 MRAD f1,
EBR-1 MRAD s1,
EBR-1 MOA f1,
EBR-1 MOA s1,
TMCQ MOA,
TMCQ MRAD,
Dead-Hold BDC dots,
Dead-Hold BDC hashes,
EBR-1 MOA f1 (4x-16x),
EBR-2B MRAD ,
EBR-1 MRAD 6x-24x s1,
EBR-1 MOA, 2.5x-10x ,
EBR-1 MRAD, 2.5-10,
JM-1 BDC,
EBR-1 MOA f1 (5-20x),
XLR
****************Weaver
EMDR,
EBX,
CIRT,
TBX,
.223 Ballistic-X
***************US Optics
Mil-Scale MPR,
Mil-Scale GAP,
MDMOA,
PCMOA Scale,
RDP MOA Scale,
MOA Scale Type 1,
RDP Mil,
C2,
CD-Mil
***************Zeiss
Rapid Z 5,
Rapid Z 7,
Rapid Z Varmint,
Rapid Z 1000,
Rapid Z 800,
Rapid Z 600,
Z-Plex (Conquest 4.5-14, 6,5-20),
Reticle 60 (Duralit, 3-12x)
************Other
ART (Holland),
Mil-Quad (SWFA),
MP-8 Dot (IOR),
6-dots MilDot,
9-dots MilDot (CenterPoint),
Mil-DotBar (Millet),
Range Finder (NcStar),
CMR, Leatherwood (Hi-Lux),
Range Finder (Osprey),
Dedal-480 (Russia),
PSO-1 (Russia),
POSP 8x42 (Russia),
PSO-1-1 (Russia),
Rapid Reticle 22-1 (PFI),
EPB MILS (Wotac),
EPB MOA (Wotac) ,
Y-TAC, BW Optics,
L5 (Lucid),
Smart Reticle (Simmons),
PAC3X (Primary Arms),
EXT, Cabelas,
MP-8 Xtreme X1 MRAD, IOR,
MP-8 Xtreme X1 MOA, IOR,
SS1-4 Donut (SWFA),
SNR (Pilad),
BDC (Truglo),
Donut (SWFA),
MSR (MakSnipe),
XPS 3-2 (EOTech),
EXPS3-4 (EOTech),
P4 Sniper (NcStar),
XR308 (EOTech),
TDRM (Counter Sniper),
Precision Plex (Pentax),
FFT (Pilad, Russia),